URL of this page: //www.nlm.nih.gov/medlineplus/ency/article/002229.htm


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 IgE to defend against the allergen. This reaction leads to allergy symptoms.


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 rubber latex
  • Pollen


Stewart GA, Richardson JP, Zhang J, Robinson C. The structure and function of allergens. In: Adkinson NF Jr., Bochner BS, Burks AW, et al., eds. In: Middleton's Allergy Principles and Practice. 8th ed. Philadelphia, PA: Elsevier Mosby; 2014:chap 26.

Update Date 2/15/2015