Epidermal Barrier Parameters in Psoriasis: Implications in Assessing Disease Severity

Abstract

Psoriasis is characterized by an aberrant immune response due to myeloid dendritic cells and T helper cells intertwining with keratinocyte hyperproliferation. Skin integrity alterations may predispose patients to physiological imbalances, such as xerosis, reduced elasticity, and increased friability. This study aims to assess the epidermal barrier dysfunction in chronic plaque psoriasis and gain a comprehensive view of the dynamic changes in the epidermal barrier during various topical therapies. Adult patients with chronic plaque psoriasis were enrolled in this observational study. For each patient, skin barrier parameters, stratum corneum hydration (SCH), transepidermal water loss (TEWL), elasticity, erythema, and melanin levels were measured in lesional and non-lesional skin. Two extensions of the initial study design, with subsequent epidermal barrier determinations, were made as follows: one in which patients with moderate psoriasis were treated with clobetasol propionate 0.5% and the second one in which mild psoriasis was treated with either clobetasol propionate 0.5% or clobetasol propionate 0.5% with 10% urea. TEWL and erythema were found to be higher in the sites affected by psoriatic lesions than the unaffected sites, while SCH and elasticity were decreased. Severe psoriasis presented with higher TEWL (p = 0.032), erythema (p = 0.002), and lower SCH (p < 0.001) compared with the mild and moderate forms. SCH significantly improved during clobetasol propionate 0.5% treatment (p = 0.015). Clobetasol propionate 0.5% with 10% urea was found to be superior to clobetasol propionate 0.5% in improving TEWL and SCH in psoriasis.