An allergy occurs when the immune system overreacts to an allergen like pollen, dust mites, or certain foods. Allergens trigger the production of IgE antibodies that attach to mast cells and cause them to release histamine and other chemicals when re-exposed, resulting in symptoms like sneezing, itchy eyes, and runny nose. While some people produce IgG antibodies in response to allergens and do not experience symptoms, those with allergies produce excessive IgE. Allergies can be treated to relieve symptoms using antihistamines, decongestants, or allergy shots, but cannot be cured. Prevention focuses on avoiding allergens and reducing indoor triggers like dust and