A drug allergy is the abnormal reaction of your immune system to a medication. A drug allergy is not the same as a drug side effect, a known possible reaction listed on a drug label. A drug allergy is also different from drug toxicity caused by an overdose of medication.

While you may not experience allergic symptoms the first time you take a drug, your body could be producing antibodies to it.

As a result, the next time you take the drug, your immune system may see it as an invader, and you’ll develop symptoms as your body releases chemicals to defend against it. These symptoms may include: skin rash, itching, swelling, breathing problems or anaphylaxis.  

Drug allergies can be hard to diagnose.If you feel confused about your symptoms and which medications are safe for you to take then it’s time to take control and see an allergist.