What immunoglobulin is mainly associated with allergic reactions?

IgE is primarily associated with allergic reactions due to its role in the immune response to allergens. When an individual is exposed to an allergen, IgE antibodies are produced and bind to mast cells and basophils. Upon subsequent exposure to the same allergen, these cells release histamine and other inflammatory mediators, leading to the symptoms commonly associated with allergies, such as itching, swelling, and respiratory distress.

This is distinct from other immunoglobulins. For example, IgM is the first antibody produced in response to an infection but is not specifically tied to allergic reactions. IgA is mainly found in mucosal areas and protects body surfaces that are exposed to foreign substances, while IgG is the most common antibody in circulation and is involved in combating various infections, but not specifically focused on allergy responses. Thus, IgE's unique role in mediating allergic reactions clearly identifies it as the correct answer.