Supplementary Material for: Childhood linear IgA dermatosis successfully treated with the combination of dapsone and sulfasalazine.

Linear IgA dermatosis (LAD) is a rare subepidermal autoimmune blistering skin disorder characterized by the linear deposition of IgA along the basal membrane. It affects primarily young children and adults, and is the most common bullous disease in the paediatric population. Dapsone represents the mainstay of treatment, to which the majority of patients show excellent initial responses with long-term remission. In recalcitrant cases, sulfonamides (sulfapyridine, sulfasalazine, sulfamethoxypyridazine) are considered second-line options either as monotherapy or in conjunction with dapsone. Most published cases of sulfonamides in childhood LAD report use of sulfapyridine or sulfamethoxypyridazine, with no published reports on sulfasalazine use in young children. We present a case of a 1-year-old child with confirmed LAD who did not respond adequately to dapsone alone. Sulfapyridine is not available in Norway, while sulfasalazine is accessible and considered a safe option for other autoimmune disorders. The addition of sulfasalazine resulted in rapid complete remission. This case thus supports sulfasalazine as a pragmatic, accessible alternative to sulfapyridine as second-line treatment in childhood LAD.