What is an allergic reaction?
A hypersensitive response, or allergic reaction, is the result of the interaction among the allergen itself, mast cells and immunoglobulin E (IgE). The result is a prompt release of inflammatory chemicals that can cause swelling of tissues, itching, engorgement of blood vessels, increased secretions and bronchospasm (tightening of muscles that surround the airways).
If the allergen is in the air, the allergic reaction will occur in the eyes, nose and/or lungs. If the allergen is ingested, the allergic reaction may primarily occur in the mouth, stomach, and intestines.