Pediatric Clinical Immunology and Allergy Fellow University of Toronto Temerty Faculty of Medicine Toronto, Ontario, Canada
Background: Drug Reaction with Eosinophilia and Systemic Symptoms (DReSS) is a severe adverse drug reaction associated with a high mortality rate in children (3%). Multiple publications have reported on patients who developed secondary hemophagocytic lymphohistiocytosis (HLH) during their DReSS disease course. However, due to the overlap between clinical and laboratory features, we hypothesize that HLH is often missed. Objective: To identify the proportion of children with DReSS who (1) have clinical and/or laboratory features of HLH, (2) are evaluated for HLH, (3) and diagnosed with HLH. Design/Methods: A scoping review of pediatric DReSS was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. In total, 301 patients aged 0-18 years with DReSS were included for analysis. Clinical and laboratory features of HLH were collected.
The median age at diagnosis was 10y (range 0.05-17y). Lymphadenopathy, hepatomegaly and splenomegaly were seen in 67% (missing n=71), 37% (missing n=169), and 22.8% (missing n=213), respectively. Laboratory features of HLH were commonly reported: anemia (22.1%, missing n=194), thrombocytopenia (19.1%, missing n=199), leukopenia (12.5%, missing n=87), neutropenia (9.6%, missing n=211), increased CRP (30.1%, missing n=206), decreased fibrinogen (1.6%, missing n=293). However, ferritin levels were rarely reported (4.6%, missing n=286). Indeed, we identified 24 cases where HLH was explicitly considered, and HLH was diagnosed in 6 cases.
Our data thus far, shows that features of HLH are common in children with DReSS, but that hallmark features of HLH were often not reported, suggesting that HLH was rarely considered. Further analysis will focus on the overlap of symptoms to identify high-risk patients, and the effect of age and the culprit agent on the development of features suggestive of HLH. The goal is that this work will contribute to proactive screening and identification of HLH in children with DReSS.