Zoology - Human Health and Diseases Question with Solution | TestHub

The exaggerated response of the immune system to certain antigens present in the environment is called allergy or hypersensitivity. 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. It happens due to substances like histamine and serotonin.