The exaggerated response of the immune system to certain antigens present in the environment is called allergy. The substances to which such an immune response is produced are called allergens. The antibodies produced to these are of IgE type. Common examples of allergens are mites in dust, pollens, animal dander, etc. Symptoms of allergic reactions include sneezing, watery eyes, running nose and difficulty in breathing. How is an allergic reaction caused by an allergen? Name a drug that can reduce the symptom of allergy.

Explanation

Allergy is because of release of certain chemicals like Histamine and Serotonin from the mast cells. Common examples of allergens are pollens, mites in dusts and animal dander. The drugs that can reduce the symptoms are anti-histamine, steroids and adrenaline.