A drug allergy is an allergic reaction to a medication. With an allergic reaction, your immune system, which fights infection and disease, reacts to the drug. This reaction can cause symptoms such as rash, fever, and trouble breathing.

What drugs cause the most drug allergies?

Different drugs have different effects on people. That said, certain drugs do tend to cause more allergic reactions than others. These include:

  • antibiotics such as penicillin and sulfa antibiotics such as sulfamethoxazole-trimethoprim
  • aspirin
  • nonsteroidal anti-inflammatory medications, such as ibuprofen
  • anticonvulsants such as carbamazepine and lamotrigine
  • drugs used in monoclonal antibody therapy such as trastuzumab and ibritumomab tiuxetan
  • chemotherapy drugs such as paclitaxel, docetaxel, and procarbazine

When our dermatologist analyzes your symptoms and test results, she can usually reach one of the following conclusions:

  • You have a drug allergy
  • You don’t have a drug allergy
  • You may have a drug allergy — with varying degrees of certainty

These conclusions can help your doctor and you in making future treatment decisions.


Interventions for a drug allergy can be divided into two general strategies:

  • Treatment for present allergy symptoms
  • Treatment that may enable you to take an allergy-causing drug if it’s medically necessary