#823 Effect of dapsone on the treatment of refractory IgA vasculitis

Abstract Background and Aims IgA vasculitis (IgAV), previously known as Henoch-Schönlein purpura, is a systemic IgA-mediated vasculitis of the small vessels commonly seen in children. The natural history of IgAV is generally self-limiting. However, one-third of patients experience symptom recurrence and a refractory course. We performed this study to examine the use of dapsone (4,4'-sulfonyldianiline or diaminodiphenyl sulfone) in refractory IgAV cases. Method A literature search of PubMed databases retrieved 16 articles published until May 31, 2023. A total of 38 patients with IgAV were recruited. Results A palpable purpura persisted in nearly all the patients with refractory course, followed by joint pain (25 of 38 patients; 69.2%). Hematuria and proteinuria were noted in 11 (28.9%) and 7 (18.4%) of the patients, respectively. Treatment response within 1-2 days was obtained in 12 of 38 patients (31.6%), compared to within ≥3 days in 22 patients (57.9%). Relapse after treatment discontinuation was reported in 21 patients (55.3%) but not in 11 patients (28.9 %). Twelve of the 38 patients (31.6%) reported adverse effects of dapsone, including arthralgia (5.3%), rash (5.3%), dapsone hypersensitivity syndrome (2.6%), methemoglobinemia (21%), and hemolysis (15.8%). These findings indicate that dapsone may have a beneficial effect on refractory IgAV. Conclusion It is observed that in spite of several adverse effects, dapsone treatment exerts a beneficial effect in IgAV patients with prolonged cutaneous manifestation refractory to corticosteroid. Close renal monitoring may be needed to discover renal involvement of IgAV. Multicenter randomized placebo-controlled trials are necessary to determine the standard dosage of dapsone at initial or tapering of treatment in IgAV patients.