An unusual reaction to some drugs is referred to as a drug allergy. The allergy-drugs test is designed to identify probable allergies to drugs that may function as allergens in the body. Using a method known as enzyme immunoassay, the test finds IgE antibodies (EIA). Our immune system responds to an allergy by producing IgE antibodies. Hives, fever, itching, swelling, and rash are among the most typical indications of a drug allergy and might appear within an hour of taking the medication. Drug allergies are more likely to occur in people with a history of other allergies or in families where drug allergies have occurred.