Majority of children at low risk for penicillin allergy are not allergic

Rachel G. Robison, MD

Rashes in childhood are common and often coincide with an antibiotic course; however, many times the rash is just as, if not more likely to be caused by the underlying illness for which the antibiotics were prescribed. This study by Vyles et al. adds pediatric data to a growing body of work in both adults and children supporting that penicillin allergy is over reported.

In several previous studies, over 95% of patients with a reported penicillin allergy are actually able to tolerate penicillins and related beta lactam antibiotics. Specific limitations of this study include a testing sample size of only 100 and a focus only on those considered “low risk” for allergy. For these and other reasons, the Vyles data may not be generalizable to a pediatric population with reported penicillin allergy. The authors go farther and propose that their questionnaire may be used as an alternative to skin testing for select ED patients.

To this effect, it is important to note that no children with possible systemic IgE-mediated symptoms were included and a proportion of subjects included had symptoms that many allergists may not even consider allergic reactions, but instead expected adverse reactions to medication, such as headache, dizziness and isolated gastrointestinal symptoms (nausea, diarrhea). These symptoms would likely not have required skin testing and graded challenge at all if evaluated by an allergist.

Regardless of the limitations of this particular study, it is important for pediatric providers to be skeptical of reported penicillin allergy in their patients and to be aware that standardized testing both exists and can be helpful in determining a patient’s risk with subsequent beta lactam antibiotic use. Taking a detailed history of a child’s reported reaction and referring to an allergist-immunologist for evaluation can help a child avoid years of unnecessary beta lactam avoidance as well as use of unnecessary broad spectrum antibiotics.

Jennifer A. Sherman, DO

Allergy to penicillin and related antibiotics is the most commonly reported drug allergy in the United States. While approximately 10% of patients self-report as being penicillin allergic, 90% of those patients are later found not to be allergic after undergoing testing. In addition, 50% of penicillin-allergic patients lose their sensitivity after 5 years, with 80% losing their sensitivity after 10 years.

Vyles et al highlights the fact that the majority of the symptoms of penicillin allergy reported by families are low-risk for true allergy. Utilizing a 17-item questionnaire, the researchers hypothesized that children presenting to the pediatric emergency department with low-risk symptoms of allergy would test as negative for true penicillin allergy. One hundred children underwent percutaneous and intradermal penicillin allergy testing followed by oral challenge; all (100%) of those children were found to have negative results for penicillin allergy after an oral challenge.

These findings are important for several reasons. Patients who are labeled as penicillin allergic are frequently treated with broad-spectrum antibiotics, which tend to have increased side effects and are often less efficacious, leading to a more complicated clinical course. Additionally, this practice contributes to antibiotic resistance and increased health care costs. Communication between families, pediatricians (in both outpatient and acute care settings), and pediatric allergy specialists in combination with available testing is crucial to removing the “penicillin-allergic” label and optimizing patient care.

Purvi Parikh, MD

Many infections, especially in the pediatric population, cause rashes. While antibiotics, such as penicillin, are often blamed for the rash, in fact, the child is merely breaking out in a rash as a response to the infection. Infections can irritate our immune system in the same way an allergen, so diagnosis can often be confusing. 

Moreover, many patients get diagnosed as “allergic” to penicillin when the symptoms they are experiencing are either a side effect of the medication or unrelated to the drug itself. For this reason, I recommend skin testing and a graded-dose challenge by a board-certified allergist to ensure that patients are not avoiding penicillin for no reason, especially among children that are low risk as the study delineates. 

The natural history of a true penicillin allergy is that 90% of patients ‘outgrow’ it over time. Even if a patient correctly has a penicillin allergy, they should be monitored down the road by a board-certified allergist to determine if the allergy is disappearing as they may not need to avoid the drug unnecessarily their entire life.