Penicillin Allergy Evaluations

Did You Know? About Penicillin

Penicillin allergy is the most common drug allergy reported by patients. However, when testing is performed, more than 90% of patients with histories of penicillin reactions are found not to be currently allergic to penicillins. We can diagnose current allergy by allergy testing in our clinic.

Frequently Asked Questions

Why is evaluation for Penicillin allergy important?

  • With penicillin listed as an allergy, doctors will usually avoid all of the penicillin family of antibiotics. If testing finds you not to be allergic, your doctors will have many more options to treat an infection, and can minimize use of alternative antibiotics which encourage resistant bacteria. This may also decrease the risk of acquiring a surgical site infection.

How long will the testing take?

  • Testing usually takes 2-3 hours

What is the testing like?

  1. You will be evaluated by a provider who will go over your history and prior reaction in detail
  2. Next, you will undergo allergy skin testing with very small needles through and then under the skin on your forearm. If negative at 20 min after placement, your likelihood of being at risk for serious allergic reactions, like anaphylaxis, is extremely small.
  3. If you do not have a skin test reaction you will undergo an oral test to prove the absence of acute allergy.  We will give you an amoxicillin capsule to take and we will closely monitor you for one hour.
  4. If you do not have a reaction, then we will remove penicillin from your allergy list and you can take the penicillin family of antibiotics in the future if needed.   You could still have a measles-like rash after days of penicillin treatment, but your risk (3-10%) is the same as the general population. 

Is testing safe?

  • Using methods developed over the past 40 years, testing for Penicillin allergy is generally very safe. It is performed very carefully, and the risk of provoking a generalized reaction is very small. You will be monitored throughout the testing procedure.
  • If you were to develop a mild skin reaction (hives/itching/redness), we can give you an oral antihistamine and perhaps a steroid to help with the itch or discomfort.  
  • In the rare event of a whole body reaction, our staff is highly trained to treat the reaction right away.  We have not seen such a reaction in more than 50 years of testing here.

How do I sign up?

  • Stop by our front desk after your appointment or give us a call to schedule an visit for penicillin allergy testing:

Allergy and Clinical Immunology Clinic
Asthma & Allergy Center
5501 Hopkins Bayview Circle
Baltimore, MD 21224

Penicillin Allergy Brochure