The Facts about a Penicillin Allergy

Penicillin is an antibiotic that is often used by doctors to treat common bacterial infections. While most people tolerate this approach well, others find that this medication causes their immune system to overreact with some serious side effects. This is called a penicillin allergy.

While anyone can develop this reaction, people who take this medication frequently are at higher risk for the problem.

Steer Clear

If you think you have a penicillin allergy, it's important to know that there are several versions of antibiotics within the penicillin family that go by different names. Any, or all, of these can pose the risk of sparking a reaction.

These include amoxicillin, ampicillin, dicloxacillin, penicillin G, penicillin V and piperacillin/tazobactam. Each of these medications targets a different area in the body and is therefore prescribed for non-allergic individuals depending on the type of infection they have. 

The Symptoms

A penicillin allergy (or response to any medications in the penicillin family) can cause a variety of symptoms, ranging from a rash or hives, itching and wheezing to trouble breathing and even a life threatening anaphylaxis reaction. However, not everyone who experiences uncomfortable symptoms when they take penicillin is actually having a true allergy. Some people get a rash or hives in response to the medication but it isn't caused by an immune system response. Only your doctor can determine for sure if you're experiencing a genuine penicillin allergy.

A Safer Alternative

The good news is that there may be some safer alternatives to turn to next time an infection strikes your body. This important finding, which comes from researchers at the Mayo Clinic, was released at the 2010 Annual Meeting of the American Academy of Allergy, Asthma and Immunology (AAAAI). The researchers report that most penicillin-allergic individuals can safely use a medication called cephalosporins. 

This is an important fact, since this class of antibiotics is closely related to penicillin and can be similarly effective. However, up until now, doctors have steered away from this option because they worried it could spark a reaction in people at risk for life-threatening penicillin reactions.

Take Care

Before you try this alternative, you should talk to your allergist and ask him to test you to be absolutely sure you can safely tolerate cephalosporins without experiencing any ill effects. Assuming that you don't show any signs of a reaction, though, this can be your drug of choice next time you're sick with an infection that needs to be treated with an antibiotic.


American Academy of Allergy, Asthma and Immunology