Atopy

Atopy is a predisposition to respond immunologically to diverse antigens or allergens, leading to CD4⁺ Th2 differentiation and overproduction of immunoglobulin E (IgE). The consequence of these cellular processes is the development of hypersensitivity reactions to allergens. The most common manifestations of atopy include allergic bronchial asthma, allergic rhinitis, atopic dermatitis, and food allergies. Two or more of these clinical conditions can coexist simultaneously in an individual or at different times. Other conditions involved in atopy include allergic conjunctivitis, IgE-mediated drug allergy, insect bites, urticaria, angioedema, and anaphylactic shock.