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 typically present in low levels in the bloodstream but can increase significantly in individuals with allergies or asthma. Elevated IgE levels are often associated with conditions like hay fever, eczema, and anaphylaxis, indicating a heightened sensitivity to specific allergens.