Epidermal barrier changes in patients with psoriasis: The role of phototherapy

Background Some skin diseases may modify epidermal barrier function. Psoriasis is a chronic multi‐systemic inflammatory disease that affects the epidermal barrier. Phototherapy is an option for treating psoriasis, but little is known about how epidermal barrier function is modified by phototherapy in psoriatic patients. Objectives (a) To compare skin homeostasis between involved and uninvolved skin in psoriatic patients with healthy controls (b) To evaluate changes in the epidermal barrier function in psoriatic patients treated with phototherapy. Methods Sixty patients with plaque‐type psoriasis and sixty gender and age‐matched healthy controls were enrolled. Temperature, transepidermal water loss (TEWL), stratum corneum hydration (SCH), pH, elasticity, erythema and melanin index were measured using non‐invasive tools in the healthy control and involved and uninvolved psoriatic skin before and after phototherapy. Results Healthy controls had lower TEWL and erythema index and higher SCH than psoriatic patients, both at uninvolved psoriatic skin and psoriasis plaques. TEWL was higher at psoriasis plaques than at uninvolved skin (19.20 vs 11.57 g/h/m2; P