Definition

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.