An allergen is a substance that can cause an allergic reaction. Allergens are substances that, in some people, the immune system recognizes as "foreign" or "dangerous" but cause no response for most people.

Information

Common allergens include:

• Animal proteins and animal dander
• Bacteria and viruses
• Chemicals
• Dust
• Drugs (such as antibiotics or medications you put on your skin)
• Foods (such as milk, chocolate, strawberries, wheat)
• Perfumes
• Plants
• Pollen
• Smoke

See also:

• Allergies
• Allergic reaction
• Food allergy
• Allergy to drugs
• Antigen
• Antibody

Update Date: 2/17/2012

Reviewed by: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

Images

Positive reaction to allergen

Patient Instructions

• Allergic rhinitis - what to ask your doctor - adult
• Allergic rhinitis - what to ask your doctor - child

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