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Allergen

An allergen is a substance that can cause an allergic reaction. In some people, the immune system recognizes allergens as foreign or dangerous. As a result, the immune system reacts by making a type of antibody called immunoglobulin E (IgE) to defend against the allergen. This reaction leads to allergy symptoms.

Information

Common allergens include:

  • Animal proteins and animal dander
  • Dust
  • Drugs (such as antibiotics or medicines you put on your skin)
  • Foods (such as egg, peanut, milk, nuts, soy, fish, animal meat, and wheat)
  • Fungal spores
  • Insect and mite feces
  • Insect bites and stings (their venom)
  • Natural latex rubber
  • Pollen

References

Stewart GA, Robinson C. The structure and function of allergens. In: Burks AW, Holgate ST, O'Hehir RE, et al, eds. Middleton's Allergy: Principles and Practice. 9th ed. Philadelphia, PA: Elsevier; 2020:chap 26.

  • Positive reaction to allergen - illustration

    Allergic reaction is a sensitivity to a specific substance, called an allergen, that is contacted through the skin, inhaled into the lungs, swallowed or injected. The body's reaction to an allergen can be mild, such as a localized rash, or life-threatening, such as anaphylactic shock.

    Positive reaction to allergen

    illustration

  • Positive reaction to allergen - illustration

    Allergic reaction is a sensitivity to a specific substance, called an allergen, that is contacted through the skin, inhaled into the lungs, swallowed or injected. The body's reaction to an allergen can be mild, such as a localized rash, or life-threatening, such as anaphylactic shock.

    Positive reaction to allergen

    illustration

 

Review Date: 2/2/2023

Reviewed By: Linda J. Vorvick, MD, Clinical Professor, Department of Family Medicine, UW Medicine, School of Medicine, University of Washington, Seattle, WA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

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