Skin tests traditionally used to predict allergies to amoxicillin, one of the most commonly prescribed antibiotics in children, are ineffective according to a new study led by a team at the Research Institute of the McGill University Health Centre (RI-MUHC) in Montreal. The findings, published in the journal JAMA Pediatrics, determined that oral provocation or challenge test, with appropriate follow up, was a more efficient and safer screening method for diagnosing non-life threatening reactions to amoxicillin in children.
“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,” says study’s lead author Dr. Moshe Ben-Shoshan, who is an allergist at the Montreal Children’s Hospital at the MUHC (MCH-MUHC) and an assistant professor of Pediatrics at McGill University. Up to 10 percent of children develop rashes while on antibiotics. “The majority are diagnosed without further evaluation as allergic to the implicated antibiotic,” Ben-Shoshan explained.
The researchers conducted the largest study of its kind to assess the use of a graded PC in children who presented with a rash due to suspected amoxicillin allergy.
- They assessed 818 children who presented to the MCH-MUHC Allergy clinic from March 2012 to April 2015.
- Unlike previous studies all children had to undergo a graded PC. Researchers observed that 94.1 per cent were tolerant to the graded PC for amoxicillin.
- From all the study’s participants, only 17 had an immediate positive reaction to amoxicillin, and only one within this group had a positive skin test. Indeed for many antibiotics (including amoxicillin), skin tests can have a high false-negative rate. Thirty one had non-immediate reactions developing more than one hour after challenge.
- All non-immediate reactions were mild and manifested mainly as skin eruptions.
