Paradoxical Effect on Epidermal Barrier of Anti-TNF-alpha Treatment for Psoriasis.

Background: Epidermal barrier defects have been described in psoriatic lesions. Transepidermal water loss (TEWL) is the measure of steady-state water vapor flux crossing the skin to the external environment, and it has been used extensively to characterize skin barrier function. We evaluated how biological treatments impact TEWL in with psocratic patients. Methods: TEWL measurements were collected from psoriatic lesions and from adjacent unaffected skin areas before introducing a biological anti-tumor necrosis factor (TNF) alpha treatment and after six months of therapy. Results: Our data show that the skin barrier function is restored after biologic therapy. Analysis of healthy skin values, indicated significant increases in TEWL. Conclusion: A restoration of TEWL on psoriatic lesions was coupled with an alteration of this parameter in nonlesional skin of all patients, underscoring the general homeostatic effect of an anti-TNF on the integrity of skin barrier. These results suggest the need of an emollient therapy in patients with psoriasis undergoing systemic biological treatment.