Abstract
A proper allergy work-up, based on the gold standard drug provocation
test (DPT), usually rules out suspected drug hypersensitivity in
children. These tests are generally open, given their high efficiency
compared to double-blind placebo-controlled DPTs. Although their
negative predictive value is excellent, no studies have calculated their
positive predictive value, highly dependent on the prevalence of the
disease. Most studies have found a rate of less than 5% to 10% of true
beta-lactam hypersensitivity in children. Given this low prevalence
(pre-test probability), a few false positive results can significantly
reduce the estimated positive predictive value. False positives may
arise from the nocebo effect during the test, including nocebo by proxy,
or from observer bias, which depends on professional expertise and
organizational circumstances. Some studies have found a high rate of
tolerance on a second DPT in children who failed the first, but these
results may be affected by the interval between the two tests, of a year
or more in most cases, reflecting a loss of hypersensitivity over time.
Taking into account the low rate of positive DPTs, with commonly mild
reactions, we suggest confirming non-severe positive DPTs with a second
provocation performed soon after the first, especially in the case of
beta-lactam antibiotics, in order to improve the diagnostic accuracy,
de-label more patients, and achieve a better estimation of true drug
hypersensitivity prevalence.