Dermoscopy and UVFD in Differentiating Palmoplantar Psoriasis and Palmoplantar Eczema

Overview

Palmoplantar psoriasis and palmoplantar eczema are chronic inflammatory skin diseases that may show similar findings on the palms and soles, such as redness, scaling, thickening of the skin, fissures, itching, and burning. Because these conditions can look alike, distinguishing between them in routine clinical practice may be difficult. This prospective, single-center observational study was designed to compare polarized dermoscopic and ultraviolet-induced fluorescence dermoscopic (UVFD) findings in adult patients with palmoplantar psoriasis and palmoplantar eczema. A total of 81 patients aged 18 years and older were included: 41 patients with clinically and/or histopathologically confirmed palmoplantar plaque psoriasis and 40 patients with palmoplantar eczema. Dermoscopic and UVFD images were evaluated to identify vascular, scaling, surface, and fluorescence-related features that may help differentiate palmoplantar psoriasis from palmoplantar eczema. The study aims to assess whether these non-invasive imaging methods can provide additional diagnostic clues to support clinical evaluation.

This prospective, single-center, observational comparative study was designed to evaluate polarized dermoscopic and ultraviolet-induced fluorescence dermoscopic (UVFD) findings in the differential diagnosis of palmoplantar psoriasis and palmoplantar eczema. Adult patients aged 18 years and older with clinically and/or histopathologically confirmed palmoplantar plaque psoriasis or palmoplantar eczema were enrolled. Patients with recent topical or systemic treatment, positive fungal examination, palmoplantar pustulosis, other confounding palmoplantar dermatoses, malignancy or immunosuppressive conditions, pregnancy, lactation, non-specific histopathological findings, or histopathological findings inconsistent with the clinical diagnosis were excluded. Demographic and clinical characteristics, lesion localization, symptom profile, relevant dermatological history, nail involvement, and disease severity parameters were recorded. Standardized polarized dermoscopic and UVFD images were obtained using a handheld dermoscope (DermLite DL5, 3Gen Inc., San Juan Capistrano, CA, USA). Imaging was performed under standardized conditions, and predefined dermoscopic and UVFD parameters relevant to inflammatory palmoplantar dermatoses were systematically evaluated. In polarized dermoscopy, vascular morphology and distribution, scale color and distribution, background color, yellow-brown globules, yellow-orange structureless areas, yellow-orange crusts, and hemorrhage within scales were assessed. In UVFD, scale distribution, scale pattern, dominant fluorescence color, additional fluorescence color, and white-yellow fluorescent foci were evaluated. Image assessments were performed by independent dermatologists blinded to the clinical diagnosis. The main objective of the study is to compare polarized dermoscopic and UVFD findings between palmoplantar psoriasis and palmoplantar eczema and to identify features that may support the clinical differentiation of these overlapping palmoplantar dermatoses. The study does not assign any treatment or intervention; all imaging procedures are non-invasive and performed for observational diagnostic evaluation.