A pilot study of skin barrier function in patients with systemic sclerosis and primary Sjögren's syndrome.

Objective: Although the close interactions between the epidermis and dermis of the skin have been widely explored, the skin barrier functions of the stratum corneum (SC) in patients with systemic sclerosis (SSc) and primary Sjögren's syndrome (pSS) are not well known. We aimed to investigate the biophysical characteristics of the skin, including transepidermal water loss (TEWL), the SC water content, erythema, and the melanin index, in patients with SSc and pSS. Methods: This case-control study included 34 patients with SSc, 31 patients with pSS, and 25 healthy controls. All parameters were measured on the extensor surface of the forearm and compared between patients and healthy controls. In patients with SSc, we performed subgroup analyses by disease subtype (diffuse and limited cutaneous SSc), the modified Rodnan skin sclerosis score (>6 or ≤6), and comorbid secondary SS status. In patients with pSS, subgroup analyses were performed by anti-Ro/SSA antibody status and the findings of salivary gland ultrasound. Results: No statistically significant differences were observed in TEWL or skin hydration between patients with SSc and pSS and healthy controls. In the pSS group, only the erythema index was significantly increased compared to the control group. In subgroup analyses, no significant differences were observed in the extent of TEWL or skin hydration by disease subtype, severity, autoantibody profile, or comorbidities. Conclusion: Patients with SSc or pSS did not exhibit specific impairments of skin barrier function or skin hydration. Further studies with larger sample sizes and age-matched controls are required.