Phenotype Switching in Pediatric Inflammatory Skin Diseases During Biologic Therapy: A Literature Review Focused on Atopic Dermatitis and Psoriasis.

Biologic therapies are highly efficacious for pediatric atopic dermatitis (AD) and psoriasis (PsO); however, their expanding use has led to increased reports of phenotype switching-a paradoxical condition where biologics induce new-onset immune-mediated dermatoses. To address clinical uncertainty regarding these complex reactions, this review evaluates real-world case reports, case series, and observational studies of pediatric AD and PsO patients who developed phenotypic switching during biologic therapy. Dupilumab is the most frequently implicated agent, commonly inducing psoriasiform, pustular, or palmoplantar eruptions in AD patients via a compensatory shift from Th2- to Th17-predominant immunity. Conversely, phenotype switching from IL-12/23 and TNF-α inhibitors remains rare in pediatric dermatology. For severe, refractory cases or AD-PsO overlaps, Janus kinase (JAK) inhibitors demonstrate significant rescue efficacy, provided appropriate baseline and ongoing laboratory monitoring is maintained. Pediatric patients experiencing biologic-induced phenotype switching can be successfully managed in clinical practice through early recognition and the implementation of the practical, evidence-based treatment algorithm proposed in this review.