Penicillin Allergy

A penicillin allergy occurs when your immune system reacts negatively to the antibiotic penicillin or an antibiotic in the penicillin family (beta-lactam antibiotics).

Penicillin is a medicine that treats infections. When you take penicillin, the medicine destroys the outer wall of bacterial cells. This ultimately kills and removes a bacterial infection from your body.

Just because you have a penicillin allergy today doesn’t mean you’ll have that same allergy in the future. An estimated 80% of people diagnosed with a penicillin allergy lose their sensitivity to the medication after 10 years.

What are common types of penicillin?

There are several types of penicillin that come as oral medicines that you take by mouth or as an injection. Types of penicillin include:

• Amoxicillin.
• Ampicillin.
• Carbenicillin.
• Dicloxacillin.
• Nafcillin.
• Oxacillin.
• Penicillin G.
• Penicillin V.
• Piperacillin.
• Ticarcillin.

Who gets a penicillin allergy?

A penicillin allergy can affect anyone whose immune system is sensitive to the medicine. You may have a higher risk of having a penicillin allergy if you have an underlying medical condition like hay fever, asthma or eczema.

How common is a penicillin allergy?

A penicillin allergy is the most common medication allergy. About 10% of all people in the United States report having a penicillin allergy, but only 1% of those people actually have an allergy. A side effect, believed to be an allergic reaction, is the difference between the reported allergy number and the actual amount of people who have an allergy.