First-Line Antituberculosis Drug Challenge Reactions in Drug Reaction With Eosinophilia and Systemic Symptoms Syndrome in an HIV Endemic Setting

Abstract

BackgroundIn high HIV prevalence settings, first line anti-tuberculosis drug (FLTD)-associated DRESS poses therapeutic challenges. Sequential and additive drug challenge (SADC) of FLTDs best identifies offending drug(s), avoids unnecessary exclusions, and optimises re-initiation of non-offending drugs. However, SADC-associated reaction complexities limit its utility. ObjectiveWe aimed to describe characteristics of FLTD-associated DRESS patients, their treatment-limiting SADC reactions and related outcomes. MethodsPatients hospitalized with FLTD-associated DRESS from 2013–2023 in a South African tertiary hospital and enrolled (retrospectively or prospectively) in an existing registry were eligible. ResultsSADC was undertaken in 41 patients. Overall, 47 classifiable reactions occurred, 34/47(72%) in 29/41(71%) patients, were treatment-limiting and 12/41(29%) reinitiated FLTDs uneventfully. Fifteen single and eight multiple drug-reactors were identified. Rifampicin, in 13/23(57%) reactors was the commonest individual offender. Ethambutol was most frequently involved in multiple drug-reactors. Median(IQR) time to a detectable reaction was 24(12-120) hours, 6/34(18%) being immediate (<6hours). Itch (65%), eosinophilia (56%), fever (41%), atypical lymphocytosis (41%), rash (38%), transaminitis (32%) and facial oedema (18%), singly or in combination were commonest features. Three reactions, one epidermal necrolysis and two liver derangements, were CTCAE grade 4 (life-threatening) events. No predictors of multiple drug-reactivity were identified, but multiple reactors were hospitalised significantly longer, 125(100-134) versus 60(45-80) days. ConclusionsSADC optimises FLTD reinitiation. However, timing, clinical presentation and severity of SADC-associated reactions following FLTD-associated DRESS is markedly heterogenous. Additionally, multiple drug-reactors are a complex group requiring longer hospitalisation, and without routine biomarkers to differentiate true multiple drug hypersensitivity from non-specific flare-ups and guide long-term drug avoidance strategies.