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Living With Allergies: A Glossary

Allergen. A foreign substance the body perceives as harmful, triggering an allergic reaction.

Allergist. A doctor who diagnoses and treats allergy-related conditions.

Recommended Related to Allergies

Food Allergies: Tips for Eating Out

Having a food allergy used to mean dining out was limited to carrying your plate from the kitchen to the porch or, at best, eating at the home of a close friend or relative who could guarantee your food offenders were nowhere in sight. Today, however, eating out is a lot easier -- and safer -- for the 2 million Americans who suffer with a mild, moderate, or even a severe food allergy. One reason: Restaurants are more aware and more prepared. "The awareness of food allergies has definitely increased...

Read the Food Allergies: Tips for Eating Out article > >

Anaphylaxis . A life-threatening allergic reaction involving the entire body. Anaphylaxis requires immediate medical attention.

Antihistamines . These drugs block histamine -- a chemical the body releases during an allergic reaction -- reducing symptoms such as itching, sneezing, and runny nose.

Asthma . A chronic inflammatory lung disease. Symptoms include breathing problems, fatigue, headaches, and cough. Asthma is often triggered by allergens, infection, exercise, cold air, or other factors.

Atopic dermatitis . See "Eczema."

Bronchitis . An inflammation of the lung's airways. Symptoms include a persistent cough and phlegm. Bronchitis is usually seen in smokers and in places with high pollution.

Contact dermatitis. An allergic reaction that occurs after skin comes in contact with an allergen such as poison ivy, washing powders, perfumes, or other irritants.

Dander. Small pieces of skin shed by an animal, similar to human dandruff. Proteins found in dander are the major causes of pet allergies.

Decongestants . Medications that shrink swollen nasal membranes, decreasing congestion and mucus, and making it easier to breathe.

Eczema . Chronic inflammation that causes a skin rash. Eczema may be a reaction to an allergen. Symptoms include itching, crusting, blisters, and scaling. Atopic dermatitis is a type of eczema that worsens after exposure to an allergen.

Epinephrine . A drug used to immediately treat severe allergic reactions. Also known as adrenaline. Epinephrine causes an increase in blood pressure and heart rate.

Inflammation. Redness, swelling, heat, and pain in a tissue. Such symptoms can be the result of an allergic reaction in the nose, lungs, or skin.

Hay fever . Also known as allergic rhinitis. Hay fever is an inflammation of the mucus membranes in the nose. Hay fever often results from allergies to pollen, dust, certain foods, and other substances. Symptoms include sneezing, itching, runny nose, and nasal congestion.

Histamine. A chemical released by the immune system after it's exposed to an allergen. It causes tissues to become swollen, inflamed, itchy, and red.

Hives . An allergic reaction of the skin. Symptoms include itchy, swollen, red bumps that appear suddenly. Hives can show up anywhere, including lips, tongue, and ears. Also known as urticaria.

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