MedlinePlus Medical Encyclopedia: Allergen

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Allergen

Contents of this page:
Illustrations Alternative names	Definition Information

Illustrations

Positive reaction to allergen

Alternative names Return to top

Allergy-causing; Irritant

Definition Return to top

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 Return to top

Common allergens include:

chemicals and plants
drugs (such as antibiotics, serums)
foods (such as milk, chocolate, strawberries, wheat)
infectious bacteria, viruses, and animal parasites
inhalants (such as dust, pollen, perfumes, smoke)
physical agents (such as heat, light, friction, radiation)

See also:

Update Date: 5/14/2003

Updated by: A.D.A.M. editorial.

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