RESUMEN
Atopic dermatitis (AD) and psoriasis are chronic inflammatory skin conditions with clinical and histopathologic features that often overlap, representing an underlying immunopathological spectrum of disease that can complicate the proper diagnosis and treatment of both conditions. We report the case of a patient with longstanding concurrent, treatment-resistant AD and psoriasis who was successfully treated with dual biologic therapy with dupilumab and guselkumab. Our case highlights the importance of considering coexisting AD and psoriasis in patients with treatment-resistant disease and the utility of dual biologic therapy. We also review an established but rare incidence of overlap between AD and psoriasis and highlight diagnostic challenges and the importance of assessing patients comprehensively. Our case also demonstrates the utility of patch testing and tissue diagnosis in patients with concurrent AD and psoriasis, as well as the importance of considering both diagnostic testing and clinical response in clinical decision-making.