Ans.
Hypersensitivity or hypersensitivity reaction includes undesirable immune reactions or allergic reactions, generally to harmless environmental substances. These reactions may be uncomfortable, damaging, or occasionally fatal and are known as the over-reactions of immune system. Symptoms include irritation and redness of infected area (such as nose or skin), runny nose, itching, and sneezing.
Thus, the correct answer is an allergy or an allergic reaction.'
