Drug Provocation Testing in Allergological Work-Up of DRESS: A Retrospective Real-Life Experience From a Specialist Centre.

Background: In drug reaction with eosinophilia and systemic symptoms (DRESS), cutaneous tests help to identify the responsible drug. However, uncertainty may persist and drug provocation tests (DPTs) could enable contraindications for essential drugs to be avoided.

Objectives: To report the experience of DPTs in a series of DRESS patients managed in a referral centre for severe drug reactions.

Methods: We performed a single-centre retrospective study (October 2015-October 2021) of patients referred for an allergological work-up after DRESS.

Results: Seventy-five patients were included (49 females, mean age 55 years, 212 suspected drugs). Cutaneous tests, realised in all patients, were positive in 38, and DPTs were performed in 39 patients (65 drugs: 41 suspected and 24 alternative drugs, all with negative cutaneous tests). DPTs were performed regardless of DRESS severity or RegiSCAR score, at full dose (FD) for 40 drugs and graduated dose (from 1/100 FD) for 25 drugs. The objective was always to avoid contra-indications or to propose alternative drugs. Mild reactions occurred following challenge with 13 drugs (all suspected drugs), of which 6 could be continued. DPTs were more often positive when more drugs were suspected or reintroduced, but less often when a high-notoriety drug was suspected and avoided.

Conclusions: DPTs can be considered in DRESS by experienced teams to avoid unnecessary contraindications for essential drugs.