Approximately 10% of people in the U.S. report they are allergic to penicillin, according to the Centers for Disease Control. In actuality, less than 1% of the population is allergic to penicillin. Correctly identifying people with true penicillin allergy can decrease the unnecessary use of broad-spectrum antibiotics, the CDC states.(1)

According to the Mayo Clinic, signs of a penicillin allergy often occur within an hour of taking the drug. Allergic reactions may include:

• Skin rash
• Hives
• Itching
• Fever
• Swelling
• Shortness of breath
• Wheezing
• Runny nose
• Itchy, watery eyes
• Anaphylaxis (2)

Research shows that true penicillin allergy is overreported.(2) The American Academy of Allergy, Asthma & Immunology advocates for penicillin allergy testing as a public health measure to combat antimicrobial resistance.(3)

To test, an allergist pricks the skin, generally on the forearm, and places a small amount of the allergen on the pricked skin. “Anyone with a positive skin test to penicillin — there’s usually itching, redness, and swelling at the site of the skin prick — is allergic and should avoid penicillin.”(4) If there is no reaction, the patient may undergo an “amoxicillin challenge,” under medical supervision. The patient is given amoxicillin and observed for one hour.(4)