What Parents Need to Know About Penicillin Allergy Labels

Alexander.W. Fender, MD¹; Jennifer L. Thompson, MD¹; Lindsay A. Thompson, MD, MS¹

Author Affiliations Article Information

JAMA Pediatr. Published online January 29, 2024. doi:10.1001/jamapediatrics.2023.6100

More than 30 million people in the US have been labeled as having a penicillin allergy and almost 75% receive this label by age 3 years, although many are not true allergies.

The most common penicillin allergy label in childhood is to amoxicillin. However, penicillin antibiotics, which include amoxicillin, are frequently the best choice to treat common childhood infections, such as ear infections, pneumonia, and strep throat. If a parent reports a penicillin allergy, sometimes the pediatrician must choose a less specific antibiotic.

How Does a Penicillin Allergy Label Affect Children?

Labeling a child as having a penicillin allergy might seem like a safe choice but can actually lead to poor long-term health outcomes. These can include increased time in the hospital, chances of dying, infections after surgery, and higher costs of care.

Many children with a penicillin allergy label are not truly allergic. Skin rashes, particularly hives, are common reasons for penicillin allergy labels in childhood. Children with common infections often get hives, sometimes while taking antibiotics, making it difficult to tell if it is an allergy or not. A pediatrician or allergist can help figure out if an antibiotic allergy label is correct.

How Is Penicillin Allergy Evaluated?

By asking questions, a pediatrician can help distinguish true allergic reactions from adverse effects of antibiotics or viral infections, such as diarrhea, upset stomach, or headache. Patients with these adverse effects or viral infections, or those with family members with penicillin allergy, do not need an allergy evaluation and can typically take these medications without increased risk of allergic reaction. At this time, penicillin allergies do not have a genetic basis.

We used to think figuring out a true allergy required skin testing followed by oral penicillin challenges to evaluate children with these labels. Updated guidelines recommend oral challenges only for children whose reactions involve certain skin rashes, such as hives.

If a child needs an oral challenge, a pediatrician or allergist gives the patient a dose of the medication and monitors in a clinic for a reaction, usually for about an hour. The health care professional may recommend a “graded” oral challenge in which the patient is given a small dose of the medication, observed for a period of time, and then given a larger dose with another period of observation. For patients with symptoms other than specific rashes or with symptoms such as vomiting or wheezing along with the rash, skin testing prior to the oral challenge is still recommended.

Children should see their pediatrician for any concern about a reaction to an antibiotic. This will allow an accurate account of the symptoms and time of onset in relation to the medication. Based on that information, your child may need a referral to an allergist. Pediatricians can do oral challenges as early as needed in childhood. Do not assume a reaction is an allergy.