ANATOMY

Detailed explanation-1: -Hypersensitivity reactions are exaggerated or inappropriate immunologic responses occurring in response to an antigen or allergen. Type I, II and III hypersensitivity reactions are known as immediate hypersensitivity reactions because they occur within 24 hours of exposure to the antigen or allergen.

Detailed explanation-2: -Type I hypersensitivities include atopic diseases, which are an exaggerated IgE mediated immune responses (i.e., allergic: asthma, rhinitis, conjunctivitis, and dermatitis), and allergic diseases, which are immune responses to foreign allergens (i.e., anaphylaxis, urticaria, angioedema, food, and drug allergies).

Detailed explanation-3: -When a harmless substance such as dust, mold, or pollen is encountered by a person who is allergic to that substance, the immune system may over react by producing antibodies that “attack” the allergen. The can cause wheezing, itching, runny nose, watery or itchy eyes, and other symptoms.

Detailed explanation-4: -An allergic reaction is an overreaction of the immune system to a substance called an allergen. Allergens include chemicals, foods, medicines, mould, plants, and pollen. Symptoms of an allergic reaction can range from mild and annoying to severe and life-threatening.

Detailed explanation-5: -Solution: The exaggerated response of the immune system to certain antigens present in the environment (that are mostly non-pathogenic) is called allergy or hypersensitivity reactions. The substances to which such an immune response is produced are called allergens.