Predicting an allergic reaction to amoxicillin in children

Published online: December 7, 2017

Amoxicillin, which belongs to the penicillin family, is one of the most frequent antibiotics prescribed to children worldwide. Approximately 5% of children report a history of penicillin allergy, most commonly rash, although only a few of these patients are truly allergic. The diagnosis of amoxicillin allergy is mostly assessed by using skin tests, followed by an oral graded challenge (giving the drug in increasing increments) in those who have a negative skin test result. However, the role of skin tests in the diagnosis of amoxicillin allergy is not clear and there are no known risk factors that can predict who will fail and who will pass the oral challenge.

A study by Faitelson and colleagues, recently published in The Journal of Allergy and Clinical Immunology: In Practice, looked for risk factors that could be used to predict who will be truly allergic to amoxicillin and examined the role of skin prick tests in the diagnosis of amoxicillin allergy. Before performing skin tests and oral graded challenges, the authors collected data about the clinical characteristics of the suspected allergic reaction, co-morbidities, family medical history regarding drug allergy, and management of the reaction.

Faitelson et al. demonstrated that it is safe to perform an oral graded challenge with amoxicillin in children, as the majority of children passed it with no complications. Only 7% of the children failed the oral challenge, but even these 7% had only minor rashes that didn't need any treatment other than antihistamines. Moreover, the study shows that children with asthma, family history of drug allergy and older age at the initial reaction were at an increased risk to fail the oral challenge and have true allergy to amoxicillin. Furthermore, Faitelson et al. showed that the skin test was not of any clinical value, as it was negative in all children, including those who failed the oral graded challenge.

This study is the first to identify specific risk factors in children with histories of penicillin allergy that increase the chance of failing an oral challenge with amoxicillin. It also leads to the conclusion that a skin prick test does not contribute to the diagnosis of amoxicillin allergy in the pediatric population and therefore the standard protocol should be re-evaluated so that unnecessary procedures can be eliminated.

The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.

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