D2.358 - Immune shift toward the IL-17 pathway: A case of paradoxical psoriasis in a patient with severe atopic dermatitis induced by dupilumab

Atopic dermatitis (AD) and psoriasis are diseases with opposing immunological mechanisms, primarily mediated by the Th2 and Th1/Th17 pathways, respectively. The use of biological drugs that inhibit these pathways can disrupt immune balance and lead to paradoxical manifestations. Cases of AD have been reported in patients treated with anti-psoriatic biologics (TNF-alpha, IL-23, IL-17), and paradoxical psoriasis in AD patients treated with IL-4/IL-13 inhibitors. Such reactions are uncommon, with the reported incidence of paradoxical psoriasis being 1-2%. The extent and severity of lesions can differ significantly among patients, with generalized lesions being less common.

We report the case of a patient with severe AD treated with dupilumab (an IL-4/IL-13 inhibitor), who developed generalized paradoxical psoriasis during the course of treatment.

A 38-year-old female patient with severe AD, initially responded well to dupilumab administered every two weeks. However, after 18 months of treatment, she developed generalized psoriasiform lesions (BSA 40%, PASI 32). The dosing interval was extended to every four weeks, and topical corticosteroids were introduced without clinical improvement. Dupilumab was subsequently discontinued, and daily treatment with upadacitinib (a JAK1 inhibitor) was initiated, resulting in significant improvement after six months.

Our case supports existing evidence that IL-4/IL-13 inhibition may contribute to an immune shift toward the IL-17 pathway. Furthermore, it highlights JAK inhibitors as an effective therapeutic alternative to restore immune balance in patients with paradoxical psoriasis. The importance of monitoring for adverse immune effects during biologic therapies is underscored.