Cutaneous IgG4-related disease treated with dupilumab

Mafalda Pestana, Department of Dermatology and Venereology, Centro Hospitalar Universitário de Lisboa Central, Lisbon, Portugal Alexandre João, Dermatology and Venereology Department – Hospital de Santo António dos Capuchos, Unidade Local de Saúde de São José, Lisbon, Portugal Susana Palma-Carlos, Centro Clínico Académico de Lisboa; Department of Immunoallergology, Unidade de Saúde Local de São José. Lisbon, Portugal Paula Leiria-Pinto, Centro Clínico Académico de Lisboa; Department of Immunoallergology, Unidade de Saúde Local de São José. Lisbon, Portugal Ana L. João, Department of Dermatology and Venereology, Hospital Santo António dos Capuchos, Unidade Local de Saúde de São José, São José, Portugal

We present a 59-year-old male with a prolonged history of severe, treatment-resistant pruritic dermatosis and associated systemic symptoms, including fatigue and diarrhea. Dermatologic examination revealed widespread erythematous-brownish papules and nodules, prompting a skin biopsy that showed dense infiltration by immunoglobulin G4 (IgG4)-positive plasma cells, leading to a diagnosis of IgG4-related disease (IgG4-RD). The patient was treated with dupilumab, resulting in complete skin lesion resolution and significant improvement in quality of life. IgG4-RD, a rare inflammatory disease with potential multiorgan involvement, frequently challenges diagnosis due to diverse clinical presentations. This case highlights dupilumab effectiveness as a novel therapy for IgG4-RD with cutaneous involvement, offering a promising alternative for patients who do not respond well to corticosteroids.

Keywords: Immunoglobulin G4-related disease. Cutaneous. Dupilumab.