By Hal B. Jenson, MD, FAAP
Professor of Pediatric and Adolescent Medicine, and Dean, Western Michigan University Homer Stryker M.D. School of Medicine, Kalamazoo, MI
SYNOPSIS: An oral dosage of amoxicillin serving as a provocative challenge is a safe and efficacious test for uncovering cutaneous allergic reactions to amoxicillin in young children. Provocative challenges should be performed in medically appropriate settings and only conducted by pediatric immunologists or allergists.
SOURCE: Mill C, Primeau MN, Medoff E, et al. Assessing the diagnostic properties of a graded oral provocation challenge for the diagnosis of immediate and nonimmediate reactions to amoxicillin children. JAMA Pediatr 2016;170:e160033.
A 3-year observational cohort study at Montreal Children’s Hospital sampled 818 children (median age, 1.7 years) with suspected amoxicillin allergy. No children with prior history of anaphylactic reaction to amoxicillin received oral provocative challenge as they were excluded from this study.
Each of the 818 participants received provocative challenge with oral amoxicillin. Of these participants, 770 (94.1%) had no apparent reaction, 17 (2.1%) had immediate, yet mild, reactions (hives), while 31 (3.8%) developed non-immediate reactions, (typically rashes or nausea)
The oral challenge’s specificity was 100%, and it had a negative predictive value of 89.1%, as well as a positive predictive value of 100%.
Patients with histories of immediate (non-anaphylactic) reaction to prior amoxicillin exposure experienced a significantly increased risk for immediate reaction to provocative challenge. On the other hand, history of prolonged rash and parental history of drug allergies were significantly associated with non-immediate reactions to the provocative challenge.
Three hundred and forty-six participants were deemed eligible for an annual follow-up, of whom 250 (72.3%) responded. Fifty-five of the follow-up patients reported having received a full regimen of amoxicillin treatment during the intervening year. Six (10.9%) of the 55 that had received the course developed non-immediate cutaneous reactions following treatment, while the remaining 49 (89.1%) reported no allergic reaction and/or full tolerance to the course of treatment.