Which class of immunoglobulin is primarily responsible for allergic reactions?

The class of immunoglobulin that is primarily responsible for allergic reactions is IgE. IgE plays a crucial role in the immune 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 histamines and other chemicals from mast cells and basophils, leading to the symptoms commonly associated with allergic reactions, such as itching, swelling, and respiratory issues.

The specific binding of IgE to allergens is essential for the development of hypersensitivity reactions. Elevated levels of IgE are often found in individuals with allergic conditions, including asthma, hay fever, and allergic rhinitis. Consequently, the role of IgE in the binding and mediation of allergy symptoms makes it the key immunoglobulin involved in these reactions.