Are You Really Allergic to Penicillin?

As we attempt to reduce the cost of medical care and limit the side effects of medications and the development of antibiotic resistance, the issue of penicillin allergy has taken on increased importance.  Penicillin and its derivatives, such as amoxicillin, are very old antibiotics. They were discovered by Alexander Fleming in 1928 in London. Despite their age, penicillins are still a very important class of antibiotics in our continuing struggle against bacterial infections.  They are also relatively inexpensive. Partly because they have been around for so long, many people report that they are allergic to penicillins. About 10% of Americans report being allergic to penicillins. But several recent studies show that 90% of the people who think they are allergic to penicillins are actually not allergic. Even if a patient was truly allergic to penicillin at some point in their life, after 10 years, 80% of those individuals are no longer allergic – they have essentially outgrown the allergy.  It is rarely a life-long allergy.

There have been two recent articles in the Journal of the American Medical Association (JAMA) that address the over-diagnosis of penicillin allergy and what to do about it.  These articles remind us that penicillins, in addition to being cheap, are some of the safest and most effective antibiotics.  When someone reports an allergy to penicillin, the physician may use a broader spectrum antibiotic instead that could cause complications, such as Clostridium difficile (C.diff) colitis, and promote more antibiotic resistance, such as methicillin-resistant Staphylococcus aureus (MRSA). The board-certified physicians at Boise Valley Asthma and Allergy Clinic are uniquely qualified to evaluate and test you for true penicillin allergy, which is an important aspect of modern day approaches to antibiotic stewardship. JAMA has also just released (January 15, 2019) a Patient Page regarding this topic, entitled “Am I Allergic to Penicillin?” which can be accessed here:


Shenoy ES, Macy E, Rowe T, Blumenthal KG. Evaluation and Management of Penicillin Allergy: A Review [published January 15, 2019]. JAMA. 2019;321(2):188-199.

Rubin R. Overdiagnosis of Penicillin Allergy Leads to Costly, Inappropriate Treatment [published November 13, 2018]. JAMA. 2018;320(18):1846-1848.