Penicillin Allergy- Should you be tested?

Penicillins are a common group of antibiotics that are used to treat bacterial infections. It is also one of the most commonly reported medication allergies. 10% of all patients in the United States report a penicillin allergy. Patients can be labeled for years with a penicillin allergy based on a childhood experience or family history. 9 out of 10 patients who report a pencillin allergy can often safely take penicillin, and the allergy can be removed from the chart. This is important because the patient who is labeled as penicillin allergic may require broad spectrum antibiotics to treat an infection. These antibiotics can often be more expensive, increase the risk of antibiotic resistance, and may not be the best antibiotic to treat the infection.

A true penicillin allergy can either occur as rash or swelling of the body. Nausea, vomiting, or diarrhea can be side effects of penicillin, but when they occur by themselves, are generally not signs of an allergic reaction. Sometimes viral rashes can be confused with a penicillin allergy. 80% of people will lose their penicillin allergy after 10 years.

A patient should consider testing if:

• The allergic reaction to penicillin cannot be remembered
• It has been more than 10 years since the reaction occurred
• A penicillin is required to treat a particular bacteria
• A patient has multiple antibiotic allergies and needs options in case of infection

Our office provides testing and evaluation of this problem. We first will take a complete history and decide if testing is appropriate. There are certain type of reactions that are so serious that testing is contraindicated. If testing is indicated we schedule a visit that can last up to 4 hours. In that visit we will place components of penicillin on the skin. If there is no mosquito bite type of reaction, we will give a penicillin orally over an hour and then observe for any reaction for 2 more hours. If there is any signs of a reaction, our office is prepared to treat the patient immediately. If there is no reaction, we ask the patient to observe for any type of delayed rash at home for the next 48 hours. If there is no reaction, then the penicillin allergy can be removed and a penicillin can then be used to treat common infections.