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Allergen

Allergens, also called antigens, are substances that can trigger an allergic reaction. Having allergies means that the body reacts to allergens as a harmful foreign substance.

Allergens may be:

  • Inhaled in the form of pollens, mold, chemicals, material from the stools of cockroaches and house dust mites, or animal dander and saliva. Animal dander is dead skin cells from an animal, such as a cat or dog. Animal hair or fur is not an allergen.
  • Eaten or taken by mouth, including foods, food supplements, home remedies, or medicines.
  • Touched, such as cosmetics, plants, soaps or detergents, chemicals, metals, or latex (causing skin or contact allergies).
  • Applied to the skin, such as artificial nails, hair extensions, or henna tattoos.
  • Injected under the skin, such as medicines or venom from the bites or stings of bees, yellow jackets, hornets, or other insects.

Allergy symptoms may be controlled by avoiding exposure to allergens. Some people need medicines or allergy shots (immunotherapy) to control their body's reactions to the allergens.

By Healthwise Staff
Primary Medical Reviewer E. Gregory Thompson, MD - Internal Medicine
Specialist Medical Reviewer Rohit K Katial, MD - Allergy and Immunology
Current as of March 12, 2014

WebMD Medical Reference from Healthwise

Last Updated: March 12, 2014
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.