Allergy is actually inappropriate response of immune system to harmless substances.Commonly cause of Allergy: 1.Genetic Factor-Some comes from ancestor and run through the families. 2.Environmental Factor- -Repeated exposure to allergens. -Diet -Pollutants Actually our immune system (mast cells, white blood cells, complement proteins etc) defend body to foreign systems. But in some people, it is hyperactive, immune system overreacts when exposed to allergens. which are harmless to the body.Result is allergic reaction.Allergens are not common to one people but different for different people. Mast cells are involved in Allergic reaction. These cells express a receptor that binds to immunoglobin. When these antigens binds to receptor(IgE), numorous response is triggeredthat causes the symptoms of allergy. Difference in the affinity of antigen favors one response to another by switching between intracellular signalling pathways. This quantitive differences (antigen affinity)determine the quality of mast cell response. Solution Allergy is actually inappropriate response of immune system to harmless substances.Commonly cause of Allergy: 1.Genetic Factor-Some comes from ancestor and run through the families. 2.Environmental Factor- -Repeated exposure to allergens. -Diet -Pollutants Actually our immune system (mast cells, white blood cells, complement proteins etc) defend body to foreign systems. But in some people, it is hyperactive, immune system overreacts when exposed to allergens. which are harmless to the body.Result is allergic reaction.Allergens are not common to one people but different for different people. Mast cells are involved in Allergic reaction. These cells express a receptor that binds to immunoglobin. When these antigens binds to receptor(IgE), numorous response is triggeredthat causes the symptoms of allergy. Difference in the affinity of antigen favors one response to another by switching between intracellular signalling pathways. This quantitive differences (antigen affinity)determine the quality of mast cell response..