Penicillin Allergy? Superwoman Allergist Says Maybe NOT!

Do you think you have Penicillin allergy?   Have you been told since childhood that you should avoid taking Penicillin?  I see many patients who have Penicillin listed as a drug allergy.  Most of the time, these patients are not referred to me specifically for Penicillin allergy; rather it is something I find out when taking their history. 

However, I always ask, “What was your reaction?”  Many times, the answer is, “Well, maybe I had a rash when I was a baby.”  That same patient is now a 50 year old woman and has gone decades without taking Penicillin.  Does she still have Penicillin allergy?  Was she ever allergic in the first place? 

Penicillin allergy – or dare I say lack thereof – was recently highlighted at the November meeting of the American College of Allergy, Asthma and Immunology meeting in Atlanta, Georgia.  Researchers found that the great majority of patients who believe they have Penicillin allergy actually may not.  In fact, in one study, conducted by physicians at the Mayo Clinic of Florida, out of 384 patients who believed they were allergic to Penicillin, 94% tested negative for the allergy.  In a second smaller study, 38 people who believed they were allergic to Penicillin were tested, and all 38-100% — tested negative.   What this tells us is that there are many people who think they have Penicillin allergy and they actually may not.  

Now, you may wonder why you should care.  Aren’t there so many other antibiotics to take?  Penicillin is a widely used, inexpensive, effective antibiotic.  We use it as first line treatment for such illnesses as strep throat, ear infections, and sinusitis.  If you are labeled with having a Penicillin allergy, you could be given an antibiotic that is stronger, and therefore can cause more side effects, as well as resistance in bacteria to some antibiotics  

Additionally, in a study published earlier this year, researchers found that when patients are admitted to the hospital and have Penicillin listed as a drug allergy, they are given stronger, broader spectrum antibiotics.  Those patients have significantly higher rates of infection in the hospital, and increased hospital stays.  

A Penicillin Allergy label is not a benign one.  It can have significant consequences on your health.  This is why we allergists love to figure out whether you are truly allergic…because we can find answers out in a relatively easy way!  When I test patients in my office, I use a three step process.  First, I skin test with something called “Pre-Pen,” which is an FDA approved skin test for Penicillin allergy.  We simply scratch the surface of the skin with Pre-Pen, and if that test is negative, we use a little needle to perform an intradermal test – this test goes just beneath the surface of the skin.  If these tests are negative, my second step is to check blood work, to look at this data another way.  If the bloodwork is negative as well, the third step is an “oral challenge” in the office.  This is when I actually give you some Amoxicillin, and make sure it is safe for you to take.  

The great majority of patients do well with all three steps.  As an allergist, when I find out you are not allergic, it is very rewarding…I know that you may not need Penicillin this year or even next, but sometime in the future you may. It could literally save your life.  I encourage you to see your local allergist to help you figure out whether you can safely take Penicillin.