Immunoglobulin E (IgE) is a type of antibody produced by the immune system. It plays a crucial role in the body's response to allergens, such as pollen, pet dander, and certain foods. When an allergen enters the body, IgE binds to it and triggers the release of chemicals like histamine, which can lead to allergic reactions. IgE is also involved in protecting against parasitic infections. While it is essential for immune defense, elevated levels of IgE can indicate allergic conditions, such as asthma, hay fever, or eczema. Testing IgE levels can help diagnose these allergies and guide treatment options.