Penicillin Allergy: Symptoms, Alternatives, and Treatment
An allergic reaction to penicillin can be terrifying. While some people only experience mild effects like a rash or hives, some people suffer from a life-threatening allergic reaction called anaphylaxis. If you or a loved one are allergic to penicillin or you are worried that you might have a penicillin allergy, here’s what you need to know.
1
Book on our free mobile app or website.
Our doctors operate in all 50 states and same day appointments are available every 15 minutes.
2
See a doctor, get treatment and a prescription at your local pharmacy.
3
Use your health insurance just like you normally would to see your doctor.
Penicillin Allergy Symptoms
Penicillin allergy symptoms may range from mild to life-threatening. They typically start within an hour of taking the drug, although less common delayed reactions may occur hours, days, or even weeks later. Symptoms of a penicillin allergy may include:
Hives
Rash
Itching
Fever
Swelling
Wheezing
Runny nose
Itchy, watery eyes
Anaphylaxis
Nausea
Vomiting
Diarrhea
Abdominal cramping
If you’ve had an allergic reaction to one type of penicillin, you may be more likely to have an allergic reaction to another penicillin or some types of cephalosporins.
What Happens If You Are Allergic to Penicillin?
If you have a mild allergy to penicillin, you’ll likely experience a mild allergic reaction. If you have a severe allergy, you may experience anaphylaxis.
Anaphylaxis is an allergic reaction that can be life-threatening and is a medical emergency. Anaphylaxis can occur when someone is severely allergic to penicillin, so it is important to be cognizant of the potential symptoms. Symptoms of anaphylaxis can include:
Closing airways causing trouble breathing
Nausea
Abdominal cramps
Vomiting
Diarrhea
Dizziness
Fast, weak pulse
Lowered blood pressure
Seizures
Loss of consciousness
If you or a loved one experiences any symptoms of anaphylaxis after taking penicillin, seek emergency medical attention (call 911) immediately.
How Long Does Penicillin Allergy Rash Last?
Even with treatment, the symptoms of a penicillin allergy, including allergy rash and skin inflammation, can last between 2–4 weeks.
With that said, everyone’s body is different, and the duration of an allergic reaction to penicillin will vary from person to person.
What Antibiotics Should You Avoid If You Are Allergic to Penicillin?
If you have a known penicillin allergy, you should try to avoid the following antibiotics due to an increased risk of an allergic reaction:
Types of penicillins to avoid:
Amoxicillin
Ampicillin
Dicloxacillin
Nafcillin
Oxacillin
Penicillin G
Penicillin V
Piperacillin
Ticarcillin
Types of cephalosporins to avoid:
Cefaclor
Cefadroxil
Cefazolin
Cefdinir
Cefotetan
Cefprozil
Cefuroxime
Cephalexin (Keflex)
Cefepime (Maxipine)
Who Is At Risk of a Penicillin Allergy?
Anyone can suffer from a penicillin allergy, but some things can increase a person’s risk are:
Having other allergies (such as seasonal or food allergies)
Experiencing an allergic reaction to another drug
Increased exposure to penicillin through things like high doses, repetitive use, or prolonged use
Illnesses known to contribute to drug reactions, such as HIV or the Epstein-Barr virus
“There is no predictable pattern to inheritance of penicillin allergy,” according to the American Academy of Allergy, Asthma, and Immunology. “You do not need to avoid penicillin if a family member is allergic to penicillin or drugs in the penicillin family.”
Avoiding a Life-Threatening Penicillin Reaction
If you know you have a penicillin allergy, there are some things you should do to ensure your safety:
Tell all healthcare workers that you encounter about your penicillin allergy. Make sure it’s clearly marked in your medical and dental records.
Wear a penicillin allergy bracelet to alert emergency medical personnel to your allergy if you are unconscious and unable to tell them yourself.
Carry emergency epinephrine such as an EpiPen. If you suffer from a life-threatening penicillin allergy, your doctor can prescribe you emergency epinephrine that can stop or reverse an anaphylactic reaction.
Penicillin Allergy Alternative Antibiotics
If you’re allergic to penicillin, your doctor may recommend treatment with alternative antibiotics. Some common penicillin allergy alternative antibiotics include:
Clindamycin (Cleocin)
Macrolides (Zithromax, ZMAX, Z-PAK)
Quinolones
Doxycycline
Minocycline
Trimethoprim-Sulfamethoxazole
Linezolid
Penicillin Allergy Treatment
There are two main ways to treat a penicillin allergy. The main treatment options for penicillin allergies are:
Treating current antibiotic side effects may include stopping the medication, taking antihistamines or corticosteroids, and treating anaphylaxis.
Drug desensitization becomes an option if penicillin is the best way to treat an infection. Drug sensitization involves starting with very small doses. Then, increasing doses are given every 15 to 30 minutes so that your body may accept the penicillin without an allergic reaction.
1
Book on our free mobile app or website.
Our doctors operate in all 50 states and same day appointments are available every 15 minutes.
2
See a doctor, get treatment and a prescription at your local pharmacy.
3
Use your health insurance just like you normally would to see your doctor.
Penicillin Allergy Test
A penicillin allergy test is available to check the likelihood of you having an allergic reaction to penicillin. A small amount of penicillin is put under your skin with a needle. If you have a penicillin allergy, an itchy, raised bump will form.
Think you may be experiencing symptoms of an allergic reaction to penicillin? Book an appointment with a PlushCare physician and get treatment today.
Read More About Antibiotics
Sources:
PlushCare is dedicated to providing you with accurate and trustworthy health information.
American Academy of Allergy, Asthma, and Immunology. Penicillin Allergy FAQ. Accessed on March 16, 2021 at https://www.aaaai.org/conditions-and-treatments/library/allergy-library/penicillin-allergy-faq
Centers for Disease Control and Prevention. Evaluation and Diagnosis of Penicillin Allergy for Healthcare Professionals. Accessed on March 16, 2021 at https://www.cdc.gov/antibiotic-use/community/for-hcp/Penicillin-Allergy.html
Mayo Clinic. Penicillin Allergy. Symptoms and Causes. Accessed on March 27, 2021 at
https://www.mayoclinic.org/diseases-conditions/penicillin-allergy/symptoms-causes/syc-20376222
National Library of Medicine. The Medical Clinics of North America. Antibiotic selection in the penicillin-allergic patient. Accessed on March 27, 2021 at
