Skin Tests to Predict Antibiotic Allergies May Be Useless

Oral provocation challenge (PC), with appropriate follow up, is more efficient and safer for screening non-life threatening reactions to amoxicillin in children than skin tests, according to a new study.

Researchers at McGill University Health Center (MUHC; Montreal, QC, Canada) conducted a cohort study among 818 children (median age 1.7 years) referred to Montreal Children’s Hospital (QC, Canada) between March 1, 2012, and April 1, 2015, with suspected allergy to amoxicillin, in order to assess the accuracy and the negative predictive value of an oral PC. In addition, 346 of the eligible children were followed up to assess reactions to subsequent use of amoxicillin in cases with negative PC results.

The results showed that 94.1% of the children tolerated the PC, with only 17 of the children having an immediate positive reaction to amoxicillin, and only one within this group with a positive graded PC. This represents a specificity of 100%, a negative predictive value of 89.1%, and a positive predictive value of 100%. Additionally, among 250 participants who responded to annual follow-up and 55 who received treatment, 89.1% reported tolerance to subsequent full treatment with amoxicillin, while 10.9% developed non-immediate cutaneous reactions. The study was published on April 4, 2016, in JAMA Pediatrics.

“Our study suggests that skin tests are essentially useless as diagnostic tests, and that we should go directly to the graded provocation test that is highly sensitive and specific,” said lead author allergologist Moshe Ben-Shoshan, MD, an assistant professor of Pediatrics at McGill University. “This is a game changer in the way physicians assess amoxicillin allergy in children, given the fact that skin tests are still the recommended screening method in hospitals.”

Amoxicillin is an antibiotic that first became available in 1972, and is on the World Health Organization (WHO) List of Essential Medicines it is one of the most commonly prescribed antibiotics in children; common side effects include nausea and rash. It may also increase the risk of yeast infections and, when used in combination with clavulanic acid, diarrhea. Up to 10% of children show a late-developing rash, sometimes referred to as the amoxicillin rash, which starts on the trunk and can spread from there. This rash is unlikely to be a true allergic reaction, and is not a contraindication for future amoxicillin usage.

Related Links:
McGill University Health Center
Montreal Children’s Hospital