MP Board · Class 12 · Biology · Human Health and DiseasesWhat is Allergy? Mention the chemical substances released during allergic reactions.

Allergy is defined as an exaggerated or hypersensitive immune response of the body's immune system to certain non-harmful foreign substances present in the environment, known as allergens (such as pollen grains, dust mites, animal dander, or mold spores). The antibodies produced to these allergens are of the IgE type. Symptoms of allergic reactions include sneezing, watery eyes, running nose, and difficulty in breathing. These allergic reactions are primarily triggered due to the release of chemicals like histamine and serotonin from the mast cells located in the tissues.