Calcipotriol-betamethasone foam modulates serum and tissue IL-17A, IL-31, IL-31RA, and substance P in mild-to-moderate psoriatic itch: A clinical and immunopathological study.

Although itching is a common psoriasis symptom, its pathogenesis remains partially elucidated. We evaluated clinical pruritus features and associated serum and tissue cytokine profiles in 25 patients with mild-to-moderate psoriasis who were treated with calcipotriol-betamethasone foam over 4 weeks. Clinical scores comprised the PASI, Dermatology Life Quality Index, pruritus Visual Analogue Scale, and Itch Severity Scale. Serum and tissue levels of IL-17A, IL-31, IL-31RA, and substance P were evaluated before and after therapy. Most patients had severe pruritus and marked QOL impairment. PASI was significantly related to Dermatology Life Quality Index, unlike itch scores. Significant sex-related differences in itching scores emerged, while Body Mass Index and lesion localization were associated with specific clinical scores. Treatment induced a marked reduction of cytokines in both serum and lesional tissue, although no correlation was found with clinical scores. Immunohistochemistry and immunofluorescence demonstrated distinct cutaneous distributions for each mediator, suggesting an interplay of neural and immune pathways, with eccrine glands as a potential anatomical hub. Our findings suggest a local modulation of the cutaneous neuro-immune axis by calcipotriol-betamethasone foam. Ultimately, given the topical nature of this therapy, tissue-level measurements provide a more accurate representation of lesional pruritus dynamics than serological data.