Drug Allergy

An allergist can diagnose a drug allergy. An allergist is a healthcare provider who specializes in diagnosing through tests and determining the best possible treatment.

Before conducting drug allergy tests, they’ll review your medical history and may ask some questions, including:

• When did you first notice symptoms?
• What are your symptoms?
• How long did your symptoms last?
• Did you take anything to help relieve your symptoms?
• Did you need to go to a doctor’s office or to the hospital to receive treatment for your symptoms?
• Do you take vitamins or herbal supplements?
• Do you have a family history of drug allergies?
• What medications are you currently taking, including over-the-counter medications?
• What medications have you taken over the last several weeks, including over-the-counter medications?
• Have you had a reaction to other drugs in the past?

What tests will be done to diagnose a drug allergy?

Depending on the drug your allergist suspects of causing the reaction, they may suggest a skin test. Skin testing is very helpful in diagnosing an allergy to penicillin-type medicines.

During a skin prick (scratch) test, your allergist will expose your body to small amounts of specific drug allergens. They’ll clean a small area of your skin on your forearm or upper back and use a thin needle (lancet) to prick your skin with possible drug allergens.

A positive reaction usually occurs within 15 minutes of exposure to the possible allergen. Your skin may change colors (red, gray or white) and develop a raised, round spot (wheal) that looks like a mosquito bite. If you have a positive reaction, it means you may have a drug allergy.

In limited instances, providers may order a blood test. A blood test may be helpful in diagnosing a severe delayed reaction, particularly if your physician is concerned that multiple organ systems may be involved.