DefinitionBy Mayo Clinic staff
Penicillin allergy is an overreaction by your immune system to penicillin and related antibiotics. If you have a penicillin allergy, your reaction to taking the antibiotic may range from a rash to anaphylaxis, a potentially life-threatening condition.
Penicillin antibiotics are widely prescribed for bacterial infections, such as strep throat. However, not all unfavorable reactions to penicillin are a true penicillin allergy.
It isn't clear why some people develop penicillin allergy. Once you've had an allergic reaction to penicillin, the simplest way to prevent penicillin allergy is to avoid penicillin and related antibiotics.
- Solensky R. Allergy to penicillins. http://www.uptodate.com/home/index.html. Accessed Oct. 17, 2011.
- Penicillin allergy. American College of Allergy, Asthma and Immunology. http://www.acaai.org/allergist/allergies/Types/drug-allergy/Pages/penicillin-allergy.aspx. Accessed Oct. 17, 2011.
- Drug hypersensitivity. The Merck Manuals: The Merck Manual for Healthcare Professionals. http://www.merckmanuals.com/professional/immunology_allergic_disorders/allergic_and_other_hypersensitivity_disorders/drug_hypersensitivity.html#v996144. Accessed Sept. 12, 2011.
- Torres MJ, et al. The complex clinical picture of b-lactam hypersensitivity: Penicillins, cephalosporins, monobactams, carbapenems, and clavams. Medical Clinics of North America. 2010;94:805.
- B-Lactams. The Merck Manuals: The Merck Manual for Healthcare Professionals. http://www.merckmanuals.com/professional/infectious_diseases/bacteria_and_antibacterial_drugs/%CE%B2-lactams.html?qt=lactam&alt=sh. Accessed Oct. 18, 2011.
- Macy E, et al. Use of commercial anti-penicillin IgE fluorometric enzyme immunoassays to diagnose penicillin allergy. Annals of Allergy, Asthma and Immunology. 2010;105:136.