Allergy Services in Mankato, Minnesota

Allergic conjunctivitis affects both eyes and is a response to an allergy-causing substance such as pollen. In response to allergens, your body produces an antibody called immunoglobulin E (IgE). This antibody triggers special cells called mast cells in the mucous lining of your eyes and airways to release inflammatory substances, including histamines. Your body's release of histamine can produce a number of allergy signs and symptoms, including red or pink eyes.

If you have allergic conjunctivitis, you may experience intense itching, tearing and inflammation of the eyes — as well as sneezing and watery nasal discharge. Most allergic conjunctivitis can be controlled with allergy eyedrops.

Anaphylaxis is a severe, potentially life-threatening allergic reaction. It can occur within seconds or minutes of exposure to something you're allergic to, such as peanuts or bee stings.

Anaphylaxis causes your immune system to release a flood of chemicals that can cause you to go into shock — your blood pressure drops suddenly and your airways narrow, blocking breathing. Signs and symptoms include a rapid, weak pulse; a skin rash; and nausea and vomiting. Common triggers include certain foods, some medications, insect venom and latex.

Anaphylaxis requires an injection of epinephrine and a follow-up trip to an emergency room. If you don't have epinephrine, you need to go to an emergency room immediately. If anaphylaxis isn't treated right away, it can be fatal.

Symptoms

Anaphylaxis symptoms usually occur within minutes of exposure to an allergen. Sometimes, however, it can occur a half-hour or longer after exposure. Signs and symptoms include:

• Skin reactions, including hives and itching and flushed or pale skin
• Low blood pressure (hypotension)
• Constriction of your airways and a swollen tongue or throat, which can cause wheezing and trouble breathing
• A weak and rapid pulse
• Nausea, vomiting or diarrhea
• Dizziness or fainting

When to see a doctor

Seek emergency medical help if you, your child or someone else you're with has a severe allergic reaction. Don't wait to see if the symptoms go away.

If the person having the attack carries an epinephrine autoinjector (EpiPen), administer it right away. Even if symptoms improve after the injection, you still need to go to an emergency room to make sure symptoms don't recur, even without more exposure to your allergen. This second reaction is called biphasic anaphylaxis.

Make an appointment to see your doctor if you or your child has had a severe allergy attack or signs and symptoms of anaphylaxis in the past.

The diagnosis and long-term management of anaphylaxis are complicated, so you'll probably need to see a doctor who specializes in allergies and immunology.

Causes

Your immune system produces antibodies that defend against foreign substances. This is good when a foreign substance is harmful, such as certain bacteria or viruses. But some people's immune systems overreact to substances that don't normally cause an allergic reaction.

Allergy symptoms aren't usually life-threatening, but a severe allergic reaction can lead to anaphylaxis. Even if you or your child has had only a mild anaphylactic reaction in the past, there's a risk of more severe anaphylaxis after another exposure to the allergy-causing substance.

The most common anaphylaxis triggers in children are food allergies, such as to peanuts, and tree nuts, fish, shellfish and milk. Besides allergy to peanuts, nuts, fish and shellfish, anaphylaxis triggers in adults include:

• Certain medications, including antibiotics, aspirin and other over-the-counter pain relievers, and the intravenous (IV) contrast used in some imaging tests
• Stings from bees, yellow jackets, wasps, hornets and fire ants
• Latex

Although not common, some people develop anaphylaxis from aerobic exercise, such as jogging, or even less intense physical activity, such as walking. Eating certain foods before exercise or exercising when the weather is hot, cold or humid also has been linked to anaphylaxis in some people. Talk with your doctor about precautions to take when exercising.

If you don't know what triggers your allergy attack, certain tests can help identify the allergen. In some cases, the cause of anaphylaxis is never identified (idiopathic anaphylaxis).

Risk factors

There aren't many known risk factors for anaphylaxis, but some things that might increase your risk include:

• Previous anaphylaxis. If you've had anaphylaxis once, your risk of having this serious reaction increases. Future reactions might be more severe than the first reaction.
• Allergies or asthma. People who have either condition are at increased risk of having anaphylaxis.
• Certain other conditions. These include heart disease and an abnormal accumulation of a certain type of white blood cell (mastocytosis).

Complications

An anaphylactic reaction can be life-threatening — it can stop your breathing or your heartbeat.

Prevention

The best way to prevent anaphylaxis is to avoid substances that cause this severe reaction. Also:

• Wear a medical alert necklace or bracelet to indicate you have an allergy to specific drugs or other substances.
• Keep an emergency kit with prescribed medications available at all times. Your doctor can advise you on the contents. If you have an epinephrine autoinjector, check the expiration date and be sure to refill your prescription before it expires.
• Be sure to alert all your doctors to medication reactions you've had.
• If you're allergic to stinging insects, use caution around them. Wear long-sleeved shirts and pants; don't walk barefoot on grass; avoid bright colors; don't wear perfumes, colognes or scented lotions; and don't drink from open soda cans outdoors. Stay calm when near a stinging insect. Move away slowly and avoid slapping at the insect.
• If you have food allergies, carefully read the labels of all the foods you buy and eat. Manufacturing processes can change, so it's important to periodically recheck the labels of foods you commonly eat.

When eating out, ask how each dish is prepared, and find out what ingredients it contains. Even small amounts of food you're allergic to can cause a serious reaction.

Be prepared

Even if you're careful, at some point you'll likely be exposed to what you're allergic to. Fortunately, you can respond quickly and effectively to an allergy emergency by knowing the signs and symptoms of an anaphylactic reaction and having a plan to quickly treat those symptoms.

Read about diagnosis, treatment and more. 

Asthma is a condition in which your airways narrow and swell and produce extra mucus. This can make breathing difficult and trigger coughing, wheezing and shortness of breath.

For some people, asthma is a minor nuisance. For others, it can be a major problem that interferes with daily activities and may lead to a life-threatening asthma attack.

Asthma can't be cured, but its symptoms can be controlled. Because asthma often changes over time, it's important that you work with your doctor to track your signs and symptoms and adjust treatment as needed.

Symptoms

Asthma symptoms vary from person to person. You may have infrequent asthma attacks, have symptoms only at certain times — such as when exercising — or have symptoms all the time.

Asthma signs and symptoms include:

• Shortness of breath
• Chest tightness or pain
• Trouble sleeping caused by shortness of breath, coughing or wheezing
• A whistling or wheezing sound when exhaling (wheezing is a common sign of asthma in children)
• Coughing or wheezing attacks that are worsened by a respiratory virus, such as a cold or the flu

Signs that your asthma is probably worsening include:

• Asthma signs and symptoms that are more frequent and bothersome
• Increasing difficulty breathing (measurable with a peak flow meter, a device used to check how well your lungs are working)
• The need to use a quick-relief inhaler more often

For some people, asthma signs and symptoms flare up in certain situations:

• Exercise-induced asthma, which may be worse when the air is cold and dry
• Occupational asthma, triggered by workplace irritants such as chemical fumes, gases or dust
• Allergy-induced asthma, triggered by airborne substances, such as pollen, mold spores, cockroach waste or particles of skin and dried saliva shed by pets (pet dander)

When to see a doctor

Seek emergency treatment

Severe asthma attacks can be life-threatening. Work with your doctor to determine what to do when your signs and symptoms worsen — and when you need emergency treatment. Signs of an asthma emergency include:

• Rapid worsening of shortness of breath or wheezing
• No improvement even after using a quick-relief inhaler, such as albuterol
• Shortness of breath when you are doing minimal physical activity

Contact your doctor

See your doctor:

• If you think you have asthma. If you have frequent coughing or wheezing that lasts more than a few days or any other signs or symptoms of asthma, see your doctor. Treating asthma early may prevent long-term lung damage and help keep the condition from worsening over time.
• To monitor your asthma after diagnosis. If you know you have asthma, work with your doctor to keep it under control. Good long-term control helps you feel better from day to day and can prevent a life-threatening asthma attack.
• If your asthma symptoms get worse. Contact your doctor right away if your medication doesn't seem to ease your symptoms or if you need to use your quick-relief inhaler more often. Don't try to solve the problem by taking more medication without consulting your doctor. Overusing asthma medication can cause side effects and may make your asthma worse.
• To review your treatment. Asthma often changes over time. Meet with your doctor regularly to discuss your symptoms and make any needed treatment adjustments.

Causes

It isn't clear why some people get asthma and others don't, but it's probably due to a combination of environmental and genetic (inherited) factors.

Asthma triggers Exposure to various irritants and substances that trigger allergies (allergens) can trigger signs and symptoms of asthma. Asthma triggers are different from person to person and can include:

• Airborne substances, such as pollen, dust mites, mold spores, pet dander or particles of cockroach waste
• Respiratory infections, such as the common cold
• Physical activity (exercise-induced asthma)
• Cold air
• Air pollutants and irritants, such as smoke
• Certain medications, including beta blockers, aspirin, ibuprofen (Advil, Motrin IB, others) and naproxen (Aleve)
• Strong emotions and stress
• Sulfites and preservatives added to some types of foods and beverages, including shrimp, dried fruit, processed potatoes, beer and wine
• Gastroesophageal reflux disease (GERD), a condition in which stomach acids back up into your throat

Risk factors

A number of factors are thought to increase your chances of developing asthma. These include:

• Having a blood relative (such as a parent or sibling) with asthma
• Having another allergic condition, such as atopic dermatitis or allergic rhinitis (hay fever)
• Being overweight
• Being a smoker
• Exposure to secondhand smoke
• Exposure to exhaust fumes or other types of pollution
• Exposure to occupational triggers, such as chemicals used in farming, hairdressing and manufacturing

Complications

Asthma complications include:

• Signs and symptoms that interfere with sleep, work or recreational activities
• Sick days from work or school during asthma flare-ups
• Permanent narrowing of the bronchial tubes (airway remodeling) that affects how well you can breathe
• Emergency room visits and hospitalizations for severe asthma attacks
• Side effects from long-term use of some medications used to stabilize severe asthma

Proper treatment makes a big difference in preventing both short-term and long-term complications caused by asthma.

Prevention

While there's no way to prevent asthma, by working together, you and your doctor can design a step-by-step plan for living with your condition and preventing asthma attacks.

• Follow your asthma action plan. With your doctor and health care team, write a detailed plan for taking medications and managing an asthma attack. Then be sure to follow your plan.
  Asthma is an ongoing condition that needs regular monitoring and treatment. Taking control of your treatment can make you feel more in control of your life in general.
• Get vaccinated for influenza and pneumonia. Staying current with vaccinations can prevent flu and pneumonia from triggering asthma flare-ups.
• Identify and avoid asthma triggers. A number of outdoor allergens and irritants — ranging from pollen and mold to cold air and air pollution — can trigger asthma attacks. Find out what causes or worsens your asthma, and take steps to avoid those triggers.
• Monitor your breathing. You may learn to recognize warning signs of an impending attack, such as slight coughing, wheezing or shortness of breath. But because your lung function may decrease before you notice any signs or symptoms, regularly measure and record your peak airflow with a home peak flow meter.
• Identify and treat attacks early. If you act quickly, you're less likely to have a severe attack. You also won't need as much medication to control your symptoms.
  When your peak flow measurements decrease and alert you to an oncoming attack, take your medication as instructed and immediately stop any activity that may have triggered the attack. If your symptoms don't improve, get medical help as directed in your action plan.
• Take your medication as prescribed. Just because your asthma seems to be improving, don't change anything without first talking to your doctor. It's a good idea to bring your medications with you to each doctor visit, so your doctor can double-check that you're using your medications correctly and taking the right dose.
• Pay attention to increasing quick-relief inhaler use. If you find yourself relying on your quick-relief inhaler, such as albuterol, your asthma isn't under control. See your doctor about adjusting your treatment.

Read about diagnosis, treatment and more.

A chronic cough is a cough that lasts eight weeks or longer in adults, or four weeks in children.

A chronic cough is more than just an annoyance. A chronic cough can interrupt your sleep and leave you feeling exhausted. Severe cases of chronic cough can cause vomiting, lightheadedness and even rib fractures.

While it can sometimes be difficult to pinpoint the problem that's triggering a chronic cough, the most common causes are tobacco use, postnasal drip, asthma and acid reflux. Fortunately, chronic cough typically disappears once the underlying problem is treated.

Symptoms

A chronic cough can occur with other signs and symptoms, which may include:

• A runny or stuffy nose
• A feeling of liquid running down the back of your throat (postnasal drip)
• Frequent throat clearing and sore throat
• Hoarseness
• Wheezing and shortness of breath
• Heartburn or a sour taste in your mouth
• In rare cases, coughing up blood

When to see a doctor

See your doctor if you have a cough that lingers for weeks, especially one that brings up sputum or blood, disturbs your sleep, or affects school or work.

Causes

An occasional cough is normal — it helps clear irritants and secretions from your lungs and prevents infection.

However, a cough that persists for weeks is usually the result of a medical problem. In many cases, more than one cause is involved.

The following causes, alone or in combination, are responsible for the majority of cases of chronic cough:

• Postnasal drip. When your nose or sinuses produce extra mucus, it can drip down the back of your throat and trigger your cough reflex. This condition is also called upper airway cough syndrome (UACS).
• Asthma. An asthma-related cough may come and go with the seasons, appear after an upper respiratory tract infection, or become worse when you're exposed to cold air or certain chemicals or fragrances. In one type of asthma (cough-variant asthma), a cough is the main symptom.
• Gastroesophageal reflux disease (GERD). In this common condition, stomach acid flows back into the tube that connects your stomach and throat (esophagus). The constant irritation can lead to chronic coughing. The coughing, in turn, worsens GERD — a vicious cycle.
• Infections. A cough can linger long after other symptoms of pneumonia, flu, a cold or other infection of the upper respiratory tract have gone away. A common but under-recognized cause of a chronic cough in adults is pertussis, also known as whooping cough.
• Blood pressure drugs. Angiotensin-converting enzyme (ACE) inhibitors, which are commonly prescribed for high blood pressure and heart failure, are known to cause chronic cough in some people.
• Chronic bronchitis. This long-standing inflammation of your major airways (bronchial tubes) can cause a cough that brings up colored sputum. Most people with chronic bronchitis are current or former smokers. Chronic bronchitis is usually part of the spectrum of smoking-related lung disease called chronic obstructive pulmonary disease (COPD). Emphysema is also incorporated under this term, and chronic bronchitis and emphysema often coexist in current or former smokers with COPD.

Less commonly, chronic cough may be caused by:

• Aspiration (food in adults; foreign bodies in children)
• Bronchiectasis (damaged airways)
• Bronchiolitis
• Cystic fibrosis
• Laryngopharyngeal reflux (stomach acid flows up into the throat)
• Lung cancer
• Nonasthmatic eosinophilic bronchitis (airway inflammation not caused by asthma)
• Sarcoidosis (collections of inflammatory cells in different parts of your body, most commonly the lungs)

Risk factors

Being a current or former smoker is one of the leading risk factors for chronic cough. Frequent exposure to secondhand smoke also can lead to coughing and lung damage.

Women tend to have more-sensitive cough reflexes, so they're more likely to develop a chronic cough than are men.

Complications

Having a persistent cough can be exhausting. Coughing can disrupt your sleep and cause a variety of other problems, including:

• Headache
• Dizziness
• Excessive sweating
• Loss of bladder control (urinary incontinence)
• Fractured ribs
• Passing out (syncope)

Read about diagnosis, treatment and more. 

Hives (urticaria) are red, itchy welts that result from a skin reaction. The welts vary in size and appear and fade repeatedly as the reaction runs its course.

The condition is considered chronic hives if the welts appear for more than six weeks and recur frequently over months or years. Often, the cause of chronic hives is not clear.

Chronic hives can be very uncomfortable and interfere with sleep and daily activities. For many people, antihistamines and anti-itch medications provide relief.

Symptoms

Signs and symptoms of chronic hives include:

• Batches of red or skin-colored welts (wheals), which can appear anywhere on the body
• Welts that vary in size, change shape, and appear and fade repeatedly as the reaction runs its course
• Itching, which may be severe
• Painful swelling (angioedema) of the lips, eyelids and inside the throat
• A tendency for signs and symptoms to flare with triggers such as heat, exercise and stress
• A tendency for signs and symptoms to persist for more than six weeks and to recur frequently and unpredictably, sometimes for months or years

Short-term (acute) hives appear suddenly and clear up within a few weeks.

When to see a doctor

See your doctor if you have severe hives or hives that continue to appear for several days.

Seek emergency medical care

Chronic hives don't put you at any sudden risk of a serious allergic reaction (anaphylaxis). If you do experience hives as part of a serious allergic reaction, seek emergency care. Signs and symptoms of anaphylaxis include dizziness, trouble breathing, and swelling of your lips, eyelids and tongue.

Causes

The welts that come with hives arise when certain cells release histamine and other chemicals into your bloodstream.

Doctors often can't identify the reason for chronic hives or why acute hives sometimes turn into a long-term problem. The skin reaction may be triggered by:

• Pain medications
• Insects or parasites
• Infection
• Scratching
• Heat or cold
• Stress
• Sunlight
• Exercise
• Alcohol or food
• Pressure on the skin, as from a tight waistband

In some cases, chronic hives may be related to an underlying illness, such as a thyroid disease or, rarely, cancer.

Complications

Chronic hives don't put you at any sudden risk of a serious allergic reaction (anaphylaxis). But if you do experience hives as part of a serious allergic reaction, seek emergency care. Signs and symptoms of anaphylaxis include dizziness, trouble breathing, and swelling of your lips, eyelids and tongue.

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Chronic sinusitis is a common condition in which the cavities around nasal passages (sinuses) become inflamed and swollen for at least 12 weeks, despite treatment attempts.

Also known as chronic rhinosinusitis, this condition interferes with drainage and causes mucus buildup. Breathing through your nose might be difficult. The area around your eyes and face might feel swollen, and you might have facial pain or tenderness.

Chronic sinusitis can be brought on by an infection, by growths in the sinuses (nasal polyps) or by a deviated nasal septum. The condition most commonly affects young and middle-aged adults, but it also can affect children.

Symptoms

At least two of the four primary signs and symptoms of chronic sinusitis must be present with confirmation of nasal inflammation for a diagnosis of the condition. They are:

• Thick, discolored discharge from the nose or drainage down the back of the throat (postnasal drainage)
• Nasal obstruction or congestion, causing difficulty breathing through your nose
• Pain, tenderness and swelling around your eyes, cheeks, nose or forehead
• Reduced sense of smell and taste in adults or cough in children

Other signs and symptoms can include:

• Ear pain
• Aching in your upper jaw and teeth
• Cough that might worsen at night
• Sore throat
• Bad breath (halitosis)
• Fatigue or irritability
• Nausea

Chronic sinusitis and acute sinusitis have similar signs and symptoms, but acute sinusitis is a temporary infection of the sinuses often associated with a cold. The signs and symptoms of chronic sinusitis last longer and often cause more fatigue. Fever isn't a common sign of chronic sinusitis, but you might have one with acute sinusitis.

When to see a doctor

You may have several episodes of acute sinusitis, lasting less than four weeks, before developing chronic sinusitis. You may be referred to an allergist or an ear, nose and throat specialist for evaluation and treatment.

Schedule an appointment with your doctor if:

• You've had sinusitis a number of times, and the condition doesn't respond to treatment
• You have sinusitis symptoms that last more than seven days
• Your symptoms don't improve after you see your doctor

See a doctor immediately if you have any of the following, which could indicate a serious infection:

• High fever
• Swelling or redness around your eyes
• Severe headache
• Confusion
• Double vision or other vision changes
• Stiff neck

Causes

Common causes of chronic sinusitis include:

• Nasal polyps. These tissue growths can block the nasal passages or sinuses.
• Deviated nasal septum. A crooked septum — the wall between the nostrils — may restrict or block sinus passages.
• Other medical conditions. The complications of cystic fibrosis, gastroesophageal reflux, or HIV and other immune system-related diseases can result in nasal blockage.
• Respiratory tract infections. Infections in your respiratory tract — most commonly colds — can inflame and thicken your sinus membranes and block mucus drainage. These infections can be viral, bacterial or fungal.
• Allergies such as hay fever. Inflammation that occurs with allergies can block your sinuses.

Risk factors

You're at increased risk of getting chronic or recurrent sinusitis if you have:

• A nasal passage abnormality, such as a deviated nasal septum or nasal polyps
• Asthma, which is highly connected to chronic sinusitis
• Aspirin sensitivity that causes respiratory symptoms
• An immune system disorder, such as HIV/AIDS or cystic fibrosis
• Hay fever or another allergic condition that affects your sinuses
• Regular exposure to pollutants such as cigarette smoke

Complications

Chronic sinusitis complications include:

• Meningitis. This infection causes inflammation of the membranes and fluid surrounding your brain and spinal cord.
• Other infections. Uncommonly, infection can spread to the bones (osteomyelitis) or skin (cellulitis).
• Partial or complete loss of sense of smell. Nasal obstruction and inflammation of the nerve for smell (olfactory nerve) can cause temporary or permanent loss of smell.
• Vision problems. If infection spreads to your eye socket, it can cause reduced vision or even blindness that can be permanent.

Prevention

Take these steps to reduce your risk of getting chronic sinusitis:

• Avoid upper respiratory infections. Minimize contact with people who have colds. Wash your hands frequently with soap and water, especially before meals.
• Manage your allergies. Work with your doctor to keep symptoms under control.
• Avoid cigarette smoke and polluted air. Tobacco smoke and air contaminants can irritate and inflame your lungs and nasal passages.
• Use a humidifier. If the air in your home is dry, such as it is if you have forced hot air heat, adding moisture to the air may help prevent sinusitis. Be sure to keep the humidifier clean and free of mold with regular, thorough cleaning.

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A drug allergy is the abnormal reaction of your immune system to a medication. Any medication — over-the-counter, prescription or herbal — is capable of inducing a drug allergy. However, a drug allergy is more likely with certain medications.

The most common signs and symptoms of drug allergy are hives, rash or fever. A drug allergy may cause serious reactions, including anaphylaxis, a life-threatening condition that affects multiple body systems.

A drug allergy is not the same as drug side effects, the known possible reactions that are listed on a drug label. A drug allergy is also distinct from drug toxicity caused by an overdose of medication.

Symptoms

Signs and symptoms of a drug allergy often occur within an hour after taking a drug. Less commonly, reactions can occur hours, days or weeks later.

Drug allergy symptoms may include:

• Skin rash
• Hives
• Itching
• Fever
• Swelling
• Shortness of breath
• Wheezing
• Runny nose
• Itchy, watery eyes

Anaphylaxis

Anaphylaxis is a rare, life-threatening reaction to a drug allergy that causes the widespread dysfunction of body systems. Signs and symptoms of anaphylaxis include:

• Tightening of the airways and throat, causing trouble breathing
• Nausea or abdominal cramps
• Vomiting or diarrhea
• Dizziness or lightheadedness
• Weak, rapid pulse
• Drop in blood pressure
• Seizure
• Loss of consciousness

Other conditions resulting from drug allergy

Less common drug allergy reactions occur days or weeks after exposure to a drug and may persist for some time after you stop taking the drug. These conditions include:

• Serum sickness, which may cause fever, joint pain, rash, swelling and nausea
• Drug-induced anemia, a reduction in red blood cells, which can cause fatigue, irregular heartbeats, shortness of breath and other symptoms
• Drug rash with eosinophilia and systemic symptoms (DRESS), which results in rash, high white blood cell counts, general swelling, swollen lymph nodes and recurrence of dormant hepatitis infection
• Inflammation in the kidneys (nephritis), which can cause fever, blood in the urine, general swelling, confusion and other symptoms

When to see a doctor

See your doctor as soon as possible if you experience signs or symptoms of drug allergy.

Call 911 if you experience signs of a severe reaction or suspected anaphylaxis after taking a medication.

Causes

A drug allergy occurs when your immune system mistakenly identifies a drug as a harmful substance, as if it were a viral or bacterial infection.

In most cases, a drug allergy develops when your immune system has become sensitive to the drug. This means that the first time you take the drug your immune system detects it as a harmful substance and develops an antibody specific to the drug.

The next time you take the drug, these specific antibodies flag the drug and direct immune system attacks on the substance. Chemicals released by this activity cause the signs and symptoms associated with an allergic reaction.

You may not be aware of your first exposure to a drug, however. Some evidence suggests that trace amounts of a drug in the food supply, such as an antibiotic, may be sufficient for the immune system to create an antibody to it.

Some allergic reactions may result from a somewhat different process. Researchers believe that some drugs can bind directly to a certain type of immune system white blood cell called a T cell. This event sets in motion the release of chemicals that cause the allergic reaction. In such cases, an allergic reaction could occur the first time you take the drug.

Drugs commonly linked to allergies

Although any drug can cause an allergic reaction, some drugs are more commonly associated with allergies. These include:

• Antibiotics, such as penicillin
• Aspirin and nonsteroidal anti-inflammatory drugs (NSAIDs)
• Chemotherapy drugs for treating cancer
• Medications for autoimmune diseases, such as rheumatoid arthritis
• Corticosteroid creams or lotions
• Medications for people with HIV or AIDS
• Bee pollen products
• Echinacea

Nonallergic drug reactions

Sometimes a reaction to a drug can produce signs and symptoms virtually the same as those of a drug allergy, but it's not triggered by immune system activity. This condition is called a nonallergic hypersensitivity reaction or pseudoallergic drug reaction.

Drugs that are more commonly associated with this condition include:

• Aspirin
• Dyes used in imaging tests (radiocontrast media)
• Opiates for treating pain
• Local anesthetics

Risk factors

While anyone can have an allergic reaction to a drug, a few factors can increase your risk. These include:

• A history of other allergies, such as food allergy or hay fever
• Allergic reaction to another drug
• A family history of drug allergy
• Increased exposure to a drug, because of high doses, repetitive use or prolonged use
• Certain illnesses commonly associated with allergic drug reactions, such as infection with HIV or the Epstein-Barr virus

Prevention

If you have a drug allergy, the best prevention is to avoid the problem drug. Steps you can take to protect yourself include the following:

• Inform health care workers. Be sure that your drug allergy is clearly identified in your medical records. Inform other health care providers, such as your dentist or any medical specialist.
• Wear a bracelet. Wear a medical alert bracelet that identifies your drug allergy. This information can ensure proper treatment in an emergency.
• Carry emergency epinephrine. If your drug allergy has caused anaphylaxis or other severe reactions, your doctor will likely prescribe a self-injecting syringe and needle device (epinephrine autoinjector). Your doctor or a member of the clinical staff will train you on how to use an autoinjector (Adrenaclick, EpiPen, Twinject, others).

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Atopic dermatitis (eczema) is a condition that makes your skin red and itchy. It's common in children but can occur at any age. Atopic dermatitis is long lasting (chronic) and tends to flare periodically. It may be accompanied by asthma or hay fever.

No cure has been found for atopic dermatitis. But treatments and self-care measures can relieve itching and prevent new outbreaks. For example, it helps to avoid harsh soaps, moisturize your skin regularly, and apply medicated creams or ointments.

Symptoms

Atopic dermatitis (eczema) signs and symptoms vary widely from person to person and include:

• Dry skin
• Itching, which may be severe, especially at night
• Red to brownish-gray patches, especially on the hands, feet, ankles, wrists, neck, upper chest, eyelids, inside the bend of the elbows and knees, and in infants, the face and scalp
• Small, raised bumps, which may leak fluid and crust over when scratched
• Thickened, cracked, scaly skin
• Raw, sensitive, swollen skin from scratching

Atopic dermatitis most often begins before age 5 and may persist into adolescence and adulthood. For some people, it flares periodically and then clears up for a time, even for several years.

When to see a doctor

See a doctor if you or your child:

• Is so uncomfortable that the condition is affecting sleep and daily activities
• Has a skin infection — look for red streaks, pus, yellow scabs
• Continues to experience symptoms despite trying home remedies

Seek immediate medical attention for your child if the rash looks infected and he or she has a fever.

Causes

Healthy skin helps retain moisture and protects you from bacteria, irritants and allergens. Eczema is related to a gene variation that affects the skin's ability to provide this protection. This allows your skin to be affected by environmental factors, irritants and allergens.

In some children, food allergies may play a role in causing eczema.

Risk factors

The primary risk factor for atopic dermatitis is having a personal or family history of eczema, allergies, hay fever or asthma.

Complications

Complications of atopic dermatitis (eczema) may include:

• Asthma and hay fever. Eczema sometimes precedes these conditions. More than half of young children with atopic dermatitis develop asthma and hay fever by age 13.
• Chronic itchy, scaly skin. A skin condition called neurodermatitis (lichen simplex chronicus) starts with a patch of itchy skin. You scratch the area, which makes it even itchier. Eventually, you may scratch simply out of habit. This condition can cause the affected skin to become discolored, thick and leathery.
• Skin infections. Repeated scratching that breaks the skin can cause open sores and cracks. These increase the risk of infection from bacteria and viruses, including the herpes simplex virus.
• Irritant hand dermatitis. This especially affects people whose work requires that their hands are often wet and exposed to harsh soaps, detergents and disinfectants.
• Allergic contact dermatitis. This condition is common in people with atopic dermatitis.
• Sleep problems. The itch-scratch cycle can cause poor sleep quality.

Prevention

The following tips may help prevent bouts of dermatitis (flares) and minimize the drying effects of bathing:

• Moisturize your skin at least twice a day. Creams, ointments and lotions seal in moisture. Choose a product or products that work well for you. Using petroleum jelly on your baby's skin may help prevent development of atopic dermatitis.
• Try to identify and avoid triggers that worsen the condition. Things that can worsen the skin reaction include sweat, stress, obesity, soaps, detergents, dust and pollen. Reduce your exposure to your triggers.
  Infants and children may experience flares from eating certain foods, including eggs, milk, soy and wheat. Talk with your child's doctor about identifying potential food allergies.
• Take shorter baths or showers. Limit your baths and showers to 10 to 15 minutes. And use warm, rather than hot, water.
• Take a bleach bath. The American Academy of Dermatology recommends considering a bleach bath to help prevent flares. A diluted-bleach bath decreases bacteria on the skin and related infections. Add 1/2 cup (118 milliliters) of household bleach, not concentrated bleach, to a 40-gallon (151-liter) bathtub filled with warm water. Measures are for a U.S.-standard-sized tub filled to the overflow drainage holes.
  Soak from the neck down or just the affected areas of skin for about 10 minutes. Do not submerge the head. Take a bleach bath no more than twice a week.
• Use only gentle soaps. Choose mild soaps. Deodorant soaps and antibacterial soaps can remove more natural oils and dry your skin.
• Dry yourself carefully. After bathing gently pat your skin dry with a soft towel and apply moisturizer while your skin is still damp.

Learn diagnosis, treatment and more.

  

In eosinophilic esophagitis (e-o-sin-o-FILL-ik uh-sof-uh-JIE-tis), a type of white blood cell (eosinophil) builds up in the lining of the tube that connects your mouth to your stomach (esophagus). This buildup, which is a reaction to foods, allergens or acid reflux, can inflame or injure the esophageal tissue. Damaged esophageal tissue can lead to difficulty swallowing or cause food to get stuck when you swallow.

Eosinophilic esophagitis is a chronic immune system disease. It has been identified only in the past two decades, but is now considered a major cause of digestive system (gastrointestinal) illness. Research is ongoing and will likely lead to revisions in the diagnosis and treatment of eosinophilic esophagitis.

Symptoms

Signs and symptoms include:

Adults:

• Difficulty swallowing (dysphagia)
• Food getting stuck in the esophagus after swallowing (impaction)
• Chest pain that is often centrally located and does not respond to antacids
• Persistent heartburn
• Upper abdominal pain
• No response to gastroesophageal reflux disease (GERD) medication
• Backflow of undigested food (regurgitation)

Children:

• Difficulty feeding, in infants
• Difficulty eating, in children
• Vomiting
• Abdominal pain
• Difficulty swallowing (dysphagia)
• Food getting stuck in the esophagus after swallowing (impaction)
• No response to GERD medication
• Failure to thrive (poor growth, malnutrition and weight loss)

When to see a doctor

Seek immediate medical attention if you experience chest pain, especially if you also have shortness of breath or jaw or arm pain. These may be symptoms of a heart attack.

Make an appointment with your doctor if you experience severe or frequent eosinophilic esophagitis symptoms. If you take over-the-counter medications for heartburn more than twice a week, see your doctor.

Causes

Eosinophils are a normal type of white blood cells present in your digestive tract. However, in eosinophilic esophagitis, you have an allergic reaction to an outside substance. The reaction may occur as follows:

• Reaction of the esophagus. The lining of your esophagus reacts to allergens, such as food or pollen.
• Multiplication of eosinophils. The eosinophils multiply in your esophagus and produce a protein that causes inflammation.
• Damage to esophagus. Inflammation can lead to scarring, narrowing and formation of excessive fibrous tissue in the lining of your esophagus.
• Dysphagia and impaction. You may have difficulty swallowing (dysphagia) or have food become stuck when you swallow (impaction).
• Additional symptoms. You may have other symptoms, such as chest pain or stomach pain.

There has been a significant increase in numbers of people diagnosed with eosinophilic esophagitis in the past decade. At first, researchers thought this was due to an increase in awareness among doctors and greater availability of tests. However, studies now suggest the disease is becoming increasingly common, parallel to the increase in asthma and allergy.

Risk factors

The following risk factors are associated with eosinophilic esophagitis:

• Climate. People who live in a cold or dry climate are more likely than those in other climates to be diagnosed with eosinophilic esophagitis.
• Season. You're more likely to be diagnosed between the spring and fall, probably because levels of pollen and other allergens are higher and people are more prone to be outdoors.
• Sex. Eosinophilic esophagitis is more common in males than in females.
• Family history. Doctors think eosinophilic esophagitis may run in the family (have a genetic component). If your family members have eosinophilic esophagitis, you have a greater chance of being diagnosed.
• Allergies and asthma. If you have food or environmental allergies, asthma, atopic dermatitis or a chronic respiratory disease, you're more likely to be diagnosed with eosinophilic esophagitis.
• Age. Originally, eosinophilic esophagitis was thought to be a childhood disease, but now it is known to be common in adults as well. The symptoms differ somewhat between children and adults.

Complications

In some people, eosinophilic esophagitis can lead to the following:

• Scarring and narrowing of the esophagus. This makes it difficult to swallow and more likely that you will have food get stuck.
• Damage to the esophagus. Because of inflammation of the esophagus, endoscopy can cause perforation or tears in the tissue that lines the esophagus. Tearing can also occur in connection with retching that some people experience when they get food stuck in the esophagus.

Read about diagnosis, treatment and more. 

Food allergy is an immune system reaction that occurs soon after eating a certain food. Even a tiny amount of the allergy-causing food can trigger signs and symptoms such as digestive problems, hives or swollen airways. In some people, a food allergy can cause severe symptoms or even a life-threatening reaction known as anaphylaxis.

Food allergy affects an estimated 6 to 8 percent of children under age 3 and up to 3 percent of adults. While there's no cure, some children outgrow their food allergy as they get older.

It's easy to confuse a food allergy with a much more common reaction known as food intolerance. While bothersome, food intolerance is a less serious condition that does not involve the immune system.

Symptoms

For some people, an allergic reaction to a particular food may be uncomfortable but not severe. For other people, an allergic food reaction can be frightening and even life-threatening. Food allergy symptoms usually develop within a few minutes to two hours after eating the offending food.

The most common food allergy signs and symptoms include:

• Tingling or itching in the mouth
• Hives, itching or eczema
• Swelling of the lips, face, tongue and throat or other parts of the body
• Wheezing, nasal congestion or trouble breathing
• Abdominal pain, diarrhea, nausea or vomiting
• Dizziness, lightheadedness or fainting

Anaphylaxis

In some people, a food allergy can trigger a severe allergic reaction called anaphylaxis. This can cause life-threatening signs and symptoms, including:

• Constriction and tightening of the airways
• A swollen throat or the sensation of a lump in your throat that makes it difficult to breathe
• Shock with a severe drop in blood pressure
• Rapid pulse
• Dizziness, lightheadedness or loss of consciousness

Emergency treatment is critical for anaphylaxis. Untreated, anaphylaxis can cause a coma or even death.

When to see a doctor

See a doctor or allergist if you have food allergy symptoms shortly after eating. If possible, see your doctor when the allergic reaction is occurring. This will help your doctor make a diagnosis.

Seek emergency treatment if you develop any signs or symptoms of anaphylaxis, such as:

• Constriction of airways that makes it difficult to breathe
• Shock with a severe drop in blood pressure
• Rapid pulse
• Dizziness or lightheadedness

Causes

When you have a food allergy, your immune system mistakenly identifies a specific food or a substance in food as something harmful. In response, your immune system triggers cells to release an antibody known as immunoglobulin E (IgE) to neutralize the allergy-causing food or food substance (the allergen).

The next time you eat even the smallest amount of that food, IgE antibodies sense it and signal your immune system to release a chemical called histamine, as well as other chemicals, into your bloodstream. These chemicals cause allergy symptoms.

In adults, the majority of food allergies are triggered by certain proteins in:

• Shellfish, such as shrimp, lobster and crab
• Peanuts
• Tree nuts, such as walnuts and pecans
• Fish

In children, food allergies are commonly triggered by proteins in:

• Peanuts
• Tree nuts
• Eggs
• Cow's milk
• Wheat
• Soy

Pollen-food allergy syndrome

Also known as oral allergy syndrome, pollen-food allergy syndrome affects many people who have hay fever. In this condition, certain fresh fruits and vegetables or nuts and spices can trigger an allergic reaction that causes the mouth to tingle or itch. In serious cases, the reaction results in swelling of the throat or even anaphylaxis.

Proteins in certain fruits, vegetables, nuts and spices cause the reaction because they're similar to allergy-causing proteins found in certain pollens. This is an example of cross-reactivity.

When you cook foods that trigger pollen-food allergy syndrome, your symptoms may be less severe.

This following table shows the specific fruits, vegetables, nuts and spices that can cause pollen-food allergy syndrome in people who are allergic to different pollens.

Exercise-induced food allergy

Eating certain foods may cause some people to feel itchy and lightheaded soon after starting to exercise. Serious cases may even involve hives or anaphylaxis. Not eating for a couple of hours before exercising and avoiding certain foods may help prevent this problem.

Food intolerance and other reactions

A food intolerance or a reaction to another substance you ate may cause the same signs and symptoms as a food allergy does — such as nausea, vomiting, cramping and diarrhea.

Depending on the type of food intolerance you have, you may be able to eat small amounts of problem foods without a reaction. By contrast, if you have a true food allergy, even a tiny amount of food may trigger an allergic reaction.

One of the tricky aspects of diagnosing food intolerance is that some people are sensitive not to the food itself but to a substance or ingredient used in the preparation of the food.

Common conditions that can cause symptoms mistaken for a food allergy include:

• Absence of an enzyme needed to fully digest a food. You may not have adequate amounts of some enzymes needed to digest certain foods. Insufficient quantities of the enzyme lactase, for example, reduce your ability to digest lactose, the main sugar in milk products. Lactose intolerance can cause bloating, cramping, diarrhea and excess gas.
• Food poisoning. Sometimes food poisoning can mimic an allergic reaction. Bacteria in spoiled tuna and other fish also can make a toxin that triggers harmful reactions.
• Sensitivity to food additives. Some people have digestive reactions and other symptoms after eating certain food additives. For example, sulfites used to preserve dried fruit, canned goods and wine can trigger asthma attacks in sensitive people.
• Histamine toxicity. Certain fish, such as tuna or mackerel, that are not refrigerated properly and that contain high amounts of bacteria may also contain high levels of histamine that trigger symptoms similar to those of food allergy. Rather than an allergic reaction, this is known as histamine toxicity or scombroid poisoning.
• Celiac disease. While celiac disease is sometimes referred to as a gluten allergy, it does not result in anaphylaxis. Like a food allergy, it does involve an immune system response, but it's a unique reaction that's more complex than a simple food allergy.
  This chronic digestive condition is triggered by eating gluten, a protein found in bread, pasta, cookies, and many other foods containing wheat, barley or rye.
  If you have celiac disease and eat foods containing gluten, an immune reaction occurs that causes damage to the surface of your small intestine, leading to an inability to absorb certain nutrients.

Risk factors

Food allergy risk factors include:

• Family history. You're at increased risk of food allergies if asthma, eczema, hives or allergies such as hay fever are common in your family.
• Other allergies. If you're already allergic to one food, you may be at increased risk of becoming allergic to another. Similarly, if you have other types of allergic reactions, such as hay fever or eczema, your risk of having a food allergy is greater.
• Age. Food allergies are more common in children, especially toddlers and infants. As you grow older, your digestive system matures and your body is less likely to absorb food or food components that trigger allergies.
  Fortunately, children typically outgrow allergies to milk, soy, wheat and eggs. Severe allergies and allergies to nuts and shellfish are more likely to be lifelong.
• Asthma. Asthma and food allergy commonly occur together. When they do, both food allergy and asthma symptoms are more likely to be severe.

Factors that may increase your risk of developing an anaphylactic reaction include:

• Having a history of asthma
• Being a teenager or younger
• Delaying use of epinephrine to treat your food allergy symptoms
• Not having hives or other skin symptoms

Complications

Complications of food allergy can include:

• Anaphylaxis. This is a life-threatening allergic reaction.
• Atopic dermatitis (eczema). Food allergy may cause a skin reaction, such as eczema.

Prevention

The best way to prevent an allergic reaction is to know and avoid foods that cause signs and symptoms. For some people, this is a mere inconvenience, but others find it a greater hardship. Also, some foods — when used as ingredients in certain dishes — may be well-hidden. This is especially true in restaurants and in other social settings.

If you know you have a food allergy, follow these steps:

• Know what you're eating and drinking. Be sure to read food labels carefully.
• If you have already had a severe reaction, wear a medical alert bracelet or necklace that lets others know that you have a food allergy in case you have a reaction and you're unable to communicate.
• Talk with your doctor about prescribing emergency epinephrine. You may need to carry an epinephrine autoinjector (Adrenaclick, EpiPen) if you're at risk of a severe allergic reaction.
• Be careful at restaurants. Be certain your server or chef is aware that you absolutely can't eat the food you're allergic to, and you need to be completely certain that the meal you order doesn't contain it. Also, make sure food isn't prepared on surfaces or in pans that contained any of the food you're allergic to.
  Don't be reluctant to make your needs known. Restaurant staff members are usually more than happy to help when they clearly understand your request.
• Plan meals and snacks before leaving home. If necessary, take a cooler packed with allergen-free foods when you travel or go to an event. If you or your child can't have the cake or dessert at a party, bring an approved special treat so no one feels left out of the celebration.

If your child has a food allergy, take these precautions to ensure his or her safety:

• Notify key people that your child has a food allergy. Talk with child care providers, school personnel, parents of your child's friends and other adults who regularly interact with your child. Emphasize that an allergic reaction can be life-threatening and requires immediate action. Make sure that your child also knows to ask for help right away if he or she reacts to food.
• Explain food allergy symptoms. Teach the adults who spend time with your child how to recognize signs and symptoms of an allergic reaction.
• Write an action plan. Your plan should describe how to care for your child when he or she has an allergic reaction to food. Provide a copy of the plan to your child's school nurse and others who care for and supervise your child.
• Have your child wear a medical alert bracelet or necklace. This alert lists your child's allergy symptoms and explains how others can provide first aid in an emergency.

Read about diagnosis, treatment and more. 

Hay fever, also called allergic rhinitis, causes cold-like signs and symptoms, such as a runny nose, itchy eyes, congestion, sneezing and sinus pressure. But unlike a cold, hay fever isn't caused by a virus. Hay fever is caused by an allergic response to outdoor or indoor allergens, such as pollen, dust mites or tiny flecks of skin and saliva shed by cats, dogs and other animals with fur or feathers (pet dander).

Besides making you miserable, hay fever can affect your performance at work or school and generally interfere with your life. But you don't have to put up with annoying symptoms. You can learn to avoid triggers and find the right treatment.

Symptoms

Hay fever signs and symptoms can include:

• Runny nose and nasal congestion
• Watery, itchy, red eyes (allergic conjunctivitis)
• Sneezing
• Cough
• Itchy nose, roof of mouth or throat
• Swollen, blue-colored skin under the eyes (allergic shiners)
• Postnasal drip
• Fatigue

Seasonal factors

Your hay fever signs and symptoms may start or worsen at a particular time of year. Triggers include:

• Tree pollen, which is common in early spring.
• Grass pollen, which is common in late spring and summer.
• Ragweed pollen, which is common in fall.
• Dust mites, cockroaches and dander from pets can occur year-round (perennial). Symptoms to indoor allergens might worsen in winter, when houses are closed up.
• Spoors from indoor and outdoor fungi and molds are considered both seasonal and perennial.

Hay fever or common cold?

Signs and symptoms can be similar, so it can be difficult to tell which one you have.

Hay fever

• Runny nose with thin, watery discharge; no fever 
• Onset immediately after exposure to allergens
• Duration As long as you're exposed to allergens 

Cold

• Runny nose with watery or thick yellow discharge; body aches; low-grade fever
• Onset 1-3 days after exposure to a cold virus
• Duration 3-7 days

When to see a doctor

See your doctor if:

• You can't find relief from your hay fever symptoms
• Allergy medications don't provide relief or cause annoying side effects
• You have another condition that can worsen hay fever symptoms, such as nasal polyps, asthma or frequent sinus infections

Many people — especially children — get used to hay fever symptoms, so they might not seek treatment until the symptoms become severe. But getting the right treatment might offer relief.

Causes

When you have hay fever, your immune system identifies a harmless airborne substance as harmful. Your immune system then produces antibodies to this harmless substance. The next time you come in contact with the substance, these antibodies signal your immune system to release chemicals such as histamine into your bloodstream, which cause a reaction that leads to the signs and symptoms of hay fever.

Risk factors

The following can increase your risk of developing hay fever:

• Having other allergies or asthma
• Having atopic dermatitis (eczema)
• Having a blood relative (such as a parent or sibling) with allergies or asthma
• Living or working in an environment that constantly exposes you to allergens — such as animal dander
• Having a mother who smoked during your first year of life

Complications

Problems that may be associated with hay fever include:

• Reduced quality of life. Hay fever can interfere with your enjoyment of activities and cause you to be less productive. For many people, hay fever symptoms lead to absences from work or school.
• Poor sleep. Hay fever symptoms can keep you awake or make it hard to stay asleep, which can lead to fatigue and a general feeling of being unwell (malaise).
• Worsening asthma. Hay fever can worsen signs and symptoms of asthma, such as coughing and wheezing.
• Sinusitis. Prolonged sinus congestion due to hay fever may increase your susceptibility to sinusitis — an infection or inflammation of the membrane that lines the sinuses.
• Ear infection. In children, hay fever often is a factor in middle ear infection (otitis media).

Prevention

There's no way to avoid getting hay fever. If you have hay fever, the best thing to do is to lessen your exposure to the allergens that cause your symptoms. Take allergy medications before you're exposed to allergens, as directed by your doctor.

Read about diagnosis, treatment and more. 

Hives — also known as urticaria (ur-tih-KAR-e-uh) — is a skin reaction that causes itchy welts, which can range in size from small spots to large blotches several inches in diameter. Hives can be triggered by exposure to certain foods, medications or other substances.

Angioedema is a related type of swelling that affects deeper layers in your skin, often around your face and lips. In most cases, hives and angioedema are harmless and don't leave any lasting marks, even without treatment.

The most common treatment for hives and angioedema is antihistamine medication. Serious angioedema can be life-threatening if swelling causes your throat or tongue to block your airway.

Symptoms

Hives

The welts associated with hives can be:

• Red or flesh-colored
• Intensely itchy
• Roughly oval or shaped like a worm
• Less than one inch to several inches across

Most hives go away within 24 hours. Chronic hives can last for months or years.

Angioedema

Angioedema is a reaction similar to hives that affects deeper layers of your skin. It most commonly appears around your eyes, cheeks or lips. Angioedema and hives can occur separately or at the same time.

Signs and symptoms of angioedema include

• Large, thick, firm welts
• Swelling and redness
• Pain or warmth in the affected areas

When to see a doctor

You can usually treat mild cases of hives or angioedema at home. See your doctor if your symptoms continue for more than a few days. Seek emergency care if you feel your throat is swelling or if you're having trouble breathing.

Causes

Hives and angioedema can be caused by:

• Foods. Many foods can trigger reactions in people with sensitivities. Shellfish, fish, peanuts, tree nuts, eggs and milk are frequent offenders.
• Medications. Almost any medication may cause hives or angioedema. Common culprits include penicillin, aspirin, ibuprofen (Advil, Motrin IB, others), naproxen (Aleve) and blood pressure medications.
• Common allergens. Other substances that can cause hives and angioedema include pollen, animal dander, latex and insect stings.
• Environmental factors. Examples include heat, cold, sunlight, water, pressure on the skin, emotional stress and exercise.
• Underlying medical conditions. Hives and angioedema also occasionally occur in response to blood transfusions, immune system disorders such as lupus, some types of cancer such as lymphoma, certain thyroid conditions, and infections with bacteria or viruses such as hepatitis, HIV, cytomegalovirus, and Epstein-Barr virus.
• Genetics. Hereditary angioedema is a rare inherited (genetic) form of the condition. It's related to low levels or abnormal functioning of certain blood proteins that play a role in regulating how your immune system functions.

Risk factors

Hives and angioedema are common. You may be at increased risk of hives and angioedema if you:

• Have had hives or angioedema before
• Have had other allergic reactions
• Have a disorder associated with hives and angioedema, such as lupus, lymphoma or thyroid disease
• Have a family history of hives, angioedema or hereditary angioedema

Complications

Severe angioedema can be life-threatening if swelling causes your throat or tongue to block your airway.

Prevention

To lower your likelihood of experiencing hives or angioedema, take the following precautions:

• Avoid known triggers. These can include foods, medications and situations, such as temperature extremes that have triggered hives or angioedema in the past.
• Keep a diary. If you suspect food is causing the problem but aren't sure which food is the trigger, keep a food and symptom diary.

Read about diagnosis, treatment and more.

Latex allergy is a reaction to certain proteins found in natural rubber latex, a product made from the rubber tree. If you have a latex allergy, your body mistakes latex for a harmful substance.

Latex allergy may cause itchy skin and hives or even anaphylaxis, a potentially life-threatening condition that can cause throat swelling and severe difficulty breathing. Your doctor can determine if you have a latex allergy or if you're at risk of developing a latex allergy.

Understanding latex allergy and knowing common sources of latex can help you prevent allergic reactions.

Symptoms

If you're allergic to latex, you're likely to have symptoms after touching latex rubber products, such as gloves or balloons. You can also have symptoms if you breathe in latex particles that are released into the air when someone removes latex gloves.

Latex allergy symptoms range from mild to severe. A reaction depends on how sensitive you are to latex and the amount of latex you touch or inhale. Your reaction can become worse with each additional latex exposure.

Mild symptoms

Mild latex allergy symptoms include:

• Itching
• Skin redness
• Hives or rash

More-severe symptoms

These include:

• Sneezing
• Runny nose
• Itchy, watery eyes
• Scratchy throat
• Difficulty breathing
• Wheezing
• Cough

Life-threatening symptoms: Anaphylaxis

The most serious allergic reaction to latex is anaphylaxis, which can be deadly. An anaphylactic (an-uh-fuh-LAK-tik) reaction develops immediately after latex exposure in highly sensitive people, but it rarely happens the first time you're exposed.

Signs and symptoms of anaphylaxis include:

• Difficulty breathing
• Hives or swelling
• Nausea and vomiting
• Wheezing
• Drop in blood pressure
• Dizziness
• Loss of consciousness
• Confusion
• Rapid or weak pulse

When to see a doctor

Seek emergency medical care if you are having or think you're having an anaphylactic reaction.

If you have less severe reactions after exposure to latex, talk to your doctor. If possible, see your doctor when you're reacting, which will aid in diagnosis.

Causes

In a latex allergy, your immune system identifies latex as a harmful substance and triggers certain antibodies to fight it off. The next time you're exposed to latex, these antibodies tell your immune system to release histamine and other chemicals into your bloodstream, producing a range of allergy signs and symptoms. The more times you are exposed to latex, the more strongly your immune system is likely to respond. This is called sensitization.

Latex allergy can occur in these ways:

• Direct contact. The most common cause of latex allergy involves touching latex-containing products, including latex gloves, condoms and balloons.
• Inhalation. Latex products, especially gloves, release latex particles, which you can breathe in when they become airborne. The amount of airborne latex from gloves differs greatly depending on the brand of glove used.

It's possible to have other skin reactions when using latex. They include:

• Allergic contact dermatitis. This reaction results from the chemical additives used during manufacturing. The main sign is a skin rash with formation of blisters 24 to 48 hours after exposure, similar to poison ivy.
• Irritant contact dermatitis. Not an allergy, this skin irritation is caused by wearing rubber gloves or exposure to the powder inside them. Signs and symptoms include dry, itchy, irritated areas, usually on the hands.

Not all latex products are made from natural sources. Products containing man-made (synthetic) latex, such as latex paint, are unlikely to cause a reaction.

Risk factors

Certain people are at greater risk of developing a latex allergy:

• People with spina bifida. The risk of latex allergy is highest in people with spina bifida — a birth defect that affects the development of the spine. People with this disorder often are exposed to latex products through early and frequent health care. People with spina bifida should always avoid latex products.
• People who undergo multiple surgeries or medical procedures. Repeated exposure to latex gloves and medical products increases your risk of developing latex allergy.
• Health care workers. If you work in health care, you're at increased risk of developing a latex allergy.
• Rubber industry workers. Repeated exposure to latex may increase sensitivity. People with a personal or family history of allergies. You're at increased risk of latex allergy if you have other allergies — such as hay fever or a food allergy — or they're common in your family.

Connection between food allergy and latex allergy

Certain fruits contain the same allergens found in latex. They include:

• Avocado
• Banana
• Chestnut
• Kiwi
• Passion fruit

If you're allergic to latex, you have a greater chance of also being allergic to these foods.

Prevention

Many common products contain latex, but you can usually find a suitable option. Prevent an allergic reaction to latex by avoiding these products:

• Dishwashing gloves
• Some types of carpeting
• Balloons
• Rubber toys
• Hot water bottles
• Baby bottle nipples
• Some disposable diapers
• Rubber bands
• Erasers
• Condoms
• Diaphragms
• Swim goggles
• Racket handles
• Motorcycle and bicycle handgrips
• Blood pressure cuffs
• Stethoscopes
• Intravenous tubing
• Syringes
• Respirators
• Electrode pads
• Surgical masks
• Dental dams

Many health care facilities use nonlatex gloves. However, because other medical products may contain latex or rubber, be sure to tell doctors, nurses, dentists and other health care workers about your allergy before all exams or procedures. Wearing a medical alert bracelet can inform others of your latex allergy.

Read about diagnosis, treatment and more.

Penicillin allergy is an abnormal reaction of your immune system to the antibiotic drug penicillin. Penicillin is prescribed for treating various bacterial infections.

Common signs and symptoms of penicillin allergy include hives, rash and itching. Severe reactions include anaphylaxis, a life-threatening condition that affects multiple body systems.

Research has shown that penicillin allergies may be over-reported — a problem that can result in the use of less-appropriate and more-expensive antibiotic treatments. Therefore, an accurate diagnosis is needed when penicillin allergy is suspected to ensure the best treatment options in the future.

Other antibiotics, particularly those with chemical properties similar to penicillin, also can result in allergic reactions.

Symptoms

Rash caused by drug allergy Drug rash Signs and symptoms of penicillin allergy often occur within an hour after taking the drug. Less commonly, reactions can occur hours, days or weeks later.

Penicillin allergy signs and symptoms may include:

• Skin rash
• Hives
• Itching
• Fever
• Swelling
• Shortness of breath
• Wheezing
• Runny nose
• Itchy, watery eyes
• Anaphylaxis

Anaphylaxis

Anaphylaxis is a rare, life-threatening allergic reaction that causes the widespread dysfunction of body systems. Signs and symptoms of anaphylaxis include:

• Tightening of the airways and throat, causing trouble breathing
• Nausea or abdominal cramps
• Vomiting or diarrhea
• Dizziness or lightheadedness
• Weak, rapid pulse
• Drop in blood pressure
• Seizures
• Loss of consciousness

Other conditions resulting from penicillin allergy

Less-common penicillin allergy reactions occur days or weeks after exposure to the drug and may persist for some time after you stop taking it. These conditions include:

• Serum sickness, which may cause fever, joint pain, rash, swelling and nausea
• Drug-induced anemia, a reduction in red blood cells, which can cause fatigue, irregular heartbeats, shortness of breath and other signs and symptoms
• Drug reaction with eosinophilia and systemic symptoms (DRESS), which results in rash, high white blood cell counts, general swelling, swollen lymph nodes and recurrence of dormant hepatitis infection
• Inflammation in the kidneys (nephritis), which can cause fever, blood in the urine, general swelling, confusion and other signs and symptoms

Adverse events that are not allergic reactions

You may experience side effects of penicillin — as happens with other medications — that are not an allergic reaction to the drug. Depending on the type of penicillin, common side effects may include mild nausea or diarrhea, headache, or vaginal itching. Signs or symptoms of an infection for which you are being treated — or unrelated symptoms — also may be mistaken as an allergic drug reaction.

When to see a doctor

See your doctor as soon as possible if you experience signs or symptoms of penicillin allergy. It's important to understand and discuss what is an allergic reaction, what is a typical side effect and what you can tolerate in taking a medication.

Call 911 or emergency medical help if you experience signs of a severe reaction or suspected anaphylaxis after taking penicillin.

Causes

Penicillin allergy occurs when your immune system becomes hypersensitive to the drug — mistakenly reacting to the drug as a harmful substance, as if it were a viral or bacterial infection.

Before the immune system can become sensitive to penicillin, you have to be exposed to the medication at least once. If and when your immune system misidentifies penicillin as a harmful substance, it develops an antibody to the drug.

The next time you take the drug, these specific antibodies flag it and direct immune system attacks on the substance. Chemicals released by this activity cause the signs and symptoms associated with an allergic reaction.

Previous exposure to penicillin may not be obvious. Some evidence suggests that trace amounts of it in the food supply may be sufficient for a person's immune system to create an antibody to it.

Penicillins and related drugs

Penicillins belong to a class of antibacterial drugs called beta-lactam antibiotics. Although the mechanisms of the drugs vary, generally they fight infections by attacking the walls of bacterial cells. In addition to penicillins, other beta-lactams more commonly associated with allergic reactions are a group called cephalosporins.

If you've had an allergic reaction to one type of penicillin, you may be — but are not necessarily — allergic to other types of penicillin or to some cephalosporins.

Penicillins include:

• Amoxicillin
• Ampicillin
• Dicloxacillin
• Nafcillin
• Oxacillin
• Penicillin G
• Penicillin V
• Piperacillin
• Ticarcillin

Cephalosporins include:

• Cefaclor
• Cefadroxil
• Cefazolin
• Cefdinir
• Cefotetan
• Cefprozil
• Cefuroxime
• Cephalexin (Keflex)
• Cefepime (Maxipine)

Risk factors

While anyone can have an allergic reaction to penicillin, a few factors can increase your risk. These include:

• A history of other allergies, such as food allergy or hay fever
• Allergic reaction to another drug
• A family history of drug allergy
• Increased exposure to penicillin, because of high doses, repetitive use or prolonged use
• Certain illnesses commonly associated with allergic drug reactions, such as infection with HIV or the Epstein-Barr virus

Prevention

If you have a penicillin allergy, the best prevention is to avoid the drug. Steps you can take to protect yourself include the following:

• Inform health care workers. Be sure that your penicillin allergy or other antibiotic allergy is clearly identified in your medical records. Inform other health care providers, such as your dentist or any medical specialist.
• Wear a bracelet. Wear a medical alert bracelet that identifies your drug allergy. This information can ensure proper treatment in an emergency.
• Carry emergency epinephrine. If your allergy has caused anaphylaxis or other severe reactions, your doctor will likely prescribe a self-injecting syringe and needle device (epinephrine autoinjector). Your doctor or a member of the clinical staff will train you on how to use an autoinjector (Adrenaclick, AUVI-Q, EpiPen, others).

Learn about diagnosis and treatment. 

Primary immunodeficiency disorders — also called primary immune disorders or primary immunodeficiency — weaken the immune system, allowing infections and other health problems to occur more easily.

Many people with primary immunodeficiency are born missing some of the body's immune defenses, which leaves them more susceptible to germs that can cause infections.

Some forms of primary immunodeficiency are so mild they may go unnoticed for years. Other types are severe enough that they're discovered almost as soon as an affected baby is born.

Treatments can boost the immune system for many types of primary immunodeficiency disorders. Most people with the condition lead relatively normal, productive lives.

Symptoms

One of the most common signs of primary immunodeficiency is an increased susceptibility to infections. You may have infections that are more frequent, longer lasting or harder to treat than are the infections of someone with a normal immune system. You may also get infections that a person with a healthy immune system likely wouldn't get (opportunistic infections).

Signs and symptoms differ depending on the type of primary immunodeficiency disorder, and they vary from person to person. Signs and symptoms of primary immunodeficiency can include:

• Frequent and recurrent pneumonia, bronchitis, sinus infections, ear infections, meningitis or skin infections
• Inflammation and infection of internal organs
• Blood disorders, such as low platelet counts or anemia
• Digestive problems, such as cramping, loss of appetite, nausea and diarrhea
• Delayed growth and development
• Autoimmune disorders, such as lupus, rheumatoid arthritis or type 1 diabetes

When to see a doctor

If your child or you have frequent, recurrent or severe infections or infections that don't respond to treatments, talk to your doctor. Early diagnosis and treatment of primary immune deficiencies may prevent infections that can cause long-term problems.

Causes

Many primary immunodeficiency disorders are inherited — passed down from one or both parents. Problems in the DNA — the genetic code that acts as a blueprint for producing the cells that make up the human body — cause many of the immune system defects in primary immunodeficiency.

There are numerous types of primary immunodeficiency disorders. In fact, research has led to a dramatic increase in the number of recognized primary immunodeficiency disorders in recent years, so they're not as rare as once thought. They can be broadly classified into six groups based on the part of the immune system that's affected:

• B cell (antibody) deficiencies
• T cell deficiencies
• Combination B and T cell deficiencies
• Defective phagocytes
• Complement deficiencies
• Unknown (idiopathic)

Risk factors

The only known risk factor is having a family history of a primary immune deficiency disorder, which increases your risk of having the condition.

Complications

Complications caused by a primary immunodeficiency disorder vary, depending on what type you have. They can include:

• Recurrent infections
• Autoimmune disorders
• Damage to heart, lungs, nervous system or digestive tract
• Slowed growth
• Increased risk of cancer
• Death from serious infection

Prevention

Because primary immune disorders are caused by genetic defects, there's no way to prevent them. But when you or your child has a weakened immune system, you can take steps to prevent infections:

• Practice good hygiene. Wash your hands with mild soap after using the toilet and before eating.
• Take care of your teeth. Brush your teeth at least twice a day.
• Eat right. A healthy, balanced diet can help prevent infections.
• Be physically active. Staying fit is important to your overall health. Ask your doctor what activities are appropriate for you.
• Get enough sleep. Try to go to sleep and get up at the same time daily and get the same number of hours of sleep every night.
• Manage stress. Some studies suggest that stress can hamper your immune system. Keep stress in check with massage, meditation, yoga, biofeedback or hobbies. Find what works for you.
• Avoid exposure. Stay away from people with colds or other infections and avoid crowds.
• Ask your doctor about vaccinations. Find out which ones you should have.

Learn about diagnosis, treatment and more.

Most reactions to insect bites and stings are mild, causing little more than redness, itching, stinging or minor swelling. Rarely, insect bites and stings, such as from a bee, a wasp, a hornet, a fire ant or a scorpion, can result in severe reactions. Some insects also carry disease, such as West Nile virus.

For mild reactions

To take care of an insect bite or sting that causes a mild reaction:

• Move to a safe area to avoid more bites or stings.
• If needed, remove the stinger.
• Wash the area with soap and water.
• Apply a cool compress. Use a cloth dampened with cold water or filled with ice. This helps reduce pain and swelling. If the injury is on an arm or leg, elevate it.
• Apply a cream, gel or lotion to the injured area. Use products containing ingredients such as hydrocortisone, pramoxine or lidocaine to help control pain. Use creams such as calamine lotion or those containing colloidal oatmeal or baking soda to help soothe itchy skin.
• Use over-the-counter medications. Try a pain reliever, such as acetaminophen (Tylenol, others) or ibuprofen (Advil, Motrin IB, others), or an antihistamine (Benadryl, Chlor-Trimeton, others).

Usually, the signs and symptoms of a bite or sting disappear in a day or two. If you're concerned — even if your reaction is minor — call your doctor.

When to seek emergency care

Call 911 or your local emergency number if the injured person experiences:

• Difficulty breathing
• Swelling of the lips, eyelids or throat
• Dizziness, faintness or confusion
• Rapid heartbeat
• Hives
• Nausea, cramps or vomiting
• A scorpion sting and is a child

Take these actions immediately while waiting for medical help:

• Ask the person if he or she is carrying an epinephrine autoinjector (EpiPen, Auvi-Q, others) to treat an allergic attack.
• If the person says he or she needs to use an autoinjector, ask whether you should help inject the medication. This is usually done by pressing the autoinjector against the person's thigh and holding it in place for several seconds.
• Loosen tight clothing and cover the person with a blanket. Don't give him or her anything to drink.
• Turn the person on a side to prevent choking if he or she is vomiting or bleeding from the mouth.
• Begin CPR if the person shows no signs of circulation, such as breathing, coughing or movement.

Vaccinations and egg allergy

Some shots to prevent illness (vaccines) contain egg proteins. In some people, these vaccines pose a risk of triggering an allergic reaction.

• Measles-mumps-rubella (MMR) vaccines are generally safe for children with egg allergy, even though eggs are used to produce them.
• Flu (influenza) vaccines sometimes contain small amounts of egg proteins. However, a flu vaccine that doesn't contain these proteins is approved for use in adults age 18 and older. And even vaccines that do have egg proteins can be given safely to most people with egg allergy without any problems. If you or your child has had a reaction to eggs in the past, talk to your doctor before getting a flu vaccination.
• Yellow fever vaccine can provoke an allergic reaction in some people who have egg allergy. It's given to travelers entering countries where there's a risk of contracting yellow fever. It's not generally recommended for people with egg allergy, but is sometimes given under medical supervision after testing for a reaction.
• Other vaccines are generally not risky for people who have egg allergy. But ask your doctor, just to be safe. If your doctor is concerned about a vaccine, he or she may test you or your child to see whether it is likely to cause a reaction.

Learn more about egg allergy