Skin Testing and Drug Provocation Tests in Epidermal Necrolysis: A French Experience.

BACKGROUND: There are limited data on the use of skin testing, other than patch testing, and challenges in the evaluation of epidermal necrolysis (EN), including Stevens-Johnson syndrome and toxic epidermal necrolysis. OBJECTIVE: To report a French multicenter experience in skin testing and challenges in EN, and investigate the factors associated with tests' positivity. METHODS: All patients who were evaluated by patch tests (PTs), skin prick tests, intradermal tests (IDTs), or drug provocation tests (DPTs) for EN between 2010 and 2020 were retrospectively included through 2 French drug reaction networks. RESULTS: In total, 113 patients were included from 8 centers. Median (interquartile range) time from EN to hypersensitivity workup was 7.9 months (5.1-15 months). All patients had PTs, 17 (15%) had skin prick tests or IDTs with delayed readings and 32 (28.3%) had DPTs. One mild reaction occurred after a DPT. Overall, 22 patients (19.5%) had positive PTs, and the only factors associated with positivity were Algorithm of Drug Causality for Epidermal Necrolysis (ALDEN) score and drug class. Only 1 IDT was positive but considered irrelevant. The DPTs were never performed to prove responsibility of a highly suspected drug but were used to confirm current tolerance of needed medications. CONCLUSIONS: Allergological workup in EN, performed by specialists involved in EN, seems safe. Skin tests, although of limited sensitivity, can be helpful for considering the reintroduction of essential drugs according to a benefit-to-risk decision. We propose an algorithm for approaching hypersensitivity testing in patients with EN, to be adapted to each patient.

Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS): Series of 49 French Pediatric Cases.

BACKGROUND: Drug reaction with eosinophilia and systemic symptoms (DRESS) is a rare and potentially fatal adverse reaction. It can be difficult to diagnose, even more so among children, because symptoms may mimic other commonly encountered pediatric conditions. OBJECTIVE: To describe clinical and laboratory features of DRESS syndrome in the pediatric population (age ≤18 years) and establish causative agents and treatment modalities. METHODS: This was a multicenter retrospective study of probable and definite DRESS cases (Registry of Sever Cutaneous Adverse Reaction score ≥ 4) in children hospitalized in 15 French university hospitals between 2000 and 2020. RESULTS: We included 49 cases. All children had fever and rash, 69.4% had lymphadenopathy, and 65.3% had facial edema. The most common organ affected was the liver (83.7%). Treatment consisted of topical corticosteroid in only 30.6% and systemic corticosteroid in 55.1%; 12.2% received intravenous immunoglobulin. Among probable and likely culprit drugs, 65% were antibiotics and 27.5% were antiepileptics, median time to DRESS symptom onset after initiation of 15 days (13 days with antibiotics and 21 days with antiepileptics). Twenty-seven children had allergy assessment for causative agents, 65.4% of whom had positive tests. CONCLUSIONS: Culprit drugs are frequently antibiotics and antiepileptic drugs, and onset is often less than 2 weeks after treatment starts, especially with antibiotics. Treatment with topical corticosteroids appears to be sufficient in the least severe cases. Treatment by systemic corticosteroid therapy remains the reference treatment in case of severe organ damage.