Effects of Immunomodulatory Therapy on the Skin Barrier Function in Patients with Psoriasis Vulgaris

Background and Objectives: Psoriasis vulgaris features epidermal barrier dysfunction. Materials and Methods: Barrier function changes were prospectively evaluated over 12 weeks during TNF-α inhibition with adalimumab, along with concurrent changes in disease severity and quality of life. Adults with moderate-to-severe plaque psoriasis initiating adalimumab (80 mg loading on day 1; 40 mg every other week thereafter, starting day 8) underwent assessments at baseline and at week 12 (n = 9; mean age 44.1 ± 14.9 years, range 20-61). Transepidermal water loss (TEWL; g/m²/h) and skin pH were measured at the elbow, lower leg, abdomen, back, and scalp; PASI, BSA, and DLQI were recorded. The measurements were standardized, though room temperature/humidity were not identical between visits. Results: The clinical indices improved markedly and TEWL also decreased at all sites-the elbow, lower leg, abdomen, back, and scalp-indicating barrier recovery; in contrast, the pH remained within a mildly acidic range at all sites. Lesion-to-non-lesion conversion occurred, and no site worsened. Conclusions: In summary, 12 weeks of adalimumab were associated with a notable clinical improvement and consistent, site-spanning reductions in TEWL, whereas skin surface pH showed no material change. TEWL appears to be a sensitive objective adjunct to clinical indices for monitoring response.