Successful Treatment of Severe Adult Linear IgA Dermatosis Using Dupilumab

ABSTRACT Linear IgA dermatosis (LAD) is a rare autoimmune subepidermal bullous dermatosis, characterised by the presence of erythematous vesiculobullous lesions arranged in rosettes or herpetiform clusters. The standard treatment involves the administration of dapsone, followed by sulfasalazine, and general corticosteroid therapy, often in combination with other immunosuppressive treatments. In this report, we present a case study of an adult patient diagnosed with LAD who was treated with dupilumab. The patient was previously treated with dapsone, but he stopped taking on his own due to myalgias, which led the bullous dermatosis to reappear. He presented with erythematic rosette‐shaped lesions predominantly on the trunk and seat, palms, and soles as well as large, flaccid bullae. Systemic corticosteroid therapy (prednisolone) at a dose of 1 mg/kg/day was started, but no improvement was seen after 15 days. Resumption of dapsone was accompanied by an increase in transaminases to 10 times the normal dose. Hepatic cytolysis and the onset of heart failure contraindicated rituximab, other immunosuppressants, and the continuation of dapsone; hence, an initial injection of 600 mg of dupilumab and 300 mg every 15 days thereafter was started. Rapid improvement with complete disappearance of the skin lesions was observed after 15 days without any recurrence after 6 months, at which point the corticosteroid therapy was reduced at 10 mg per day. Dupilumab was continued at the same dosage. Although the efficacy of dupilumab is now well established in bullous pemphigoid, our observation demonstrates its potential efficacy in other junctional bullous diseases, particularly IgA, in cases of corticoresistance or contraindication to immunosuppressive treatments.