Q.Histamine is secreted by :

An allergy is an exaggerated immune response to a substance (an allergen, such as dust, pollen, animal dander, or certain foods) that is harmless to most people. On first exposure, a susceptible person's immune system produces IgE antibodies against the allergen, which attach to mast cells; on later exposure, allergen binding to this IgE triggers mast cells to release histamine and other chemicals, producing sneezing, watery/itchy eyes, skin rashes, and, in the airways, wheezing an …