Immunoglobulin E (IgE) Defined

Immunoglobulin E (IgE) are antibodies produced by the immune system. 

In an allergy, your body mistakenly recognizes common allergens such as pollen or foods as threats, and produces antibodies called Immunoglobulin E (IgE). These antibodies travel to cells that release chemicals, causing an allergic reaction. This reaction usually causes symptoms in the nose, lungs, throat, or on the skin. 

Each type of IgE specifically targets a certain allergen. That's why some people are only allergic to cat dander (they only have the IgE antibodies specific to cat dander); while others have allergic reactions to multiple allergens because they have many more types of IgE antibodies.

Learn more about allergy symptoms, diagnosis, treatment and management.

Learn more about anaphylaxis.

The AAAAI's Find an Allergist / Immunologist service is a trusted resource to help you find a specialist close to home.

6/17/2026