The point prevalence of atopic dermatitis (AD) among Korean adults visiting the Health Service Center for health check-ups was assessed. AD was diagnosed based on the questionnaires filled by patients and through physical examination by dermatologists. A total of 3,563 persons completed the questionnaires, and 2,032 persons were examined by the dermatologists. According to the questionnaires, the prevalence of AD was 7.1%, and from the dermatologists' examination, it was 2.6% overall, which decreased with age significantly. The prevalence in men was higher than that of women. Grading the severity of AD according to their eczema area and severity index scores, 70.6% were classified as being mild, 25.5% moderate, and 3.9% severe. Interestingly, concomitance of psoriasis and AD was found in 0.5% of those examined by the dermatologists. Our results suggest that AD is one of the most common skin diseases not only in children but also in adults in Korea.

Excessive accumulation of collagen contributes to the fibrotic process. Several experimental studies have shown that IFN-gamma is effective in preventing fibrogenesis. IL-18, originally identified as an IFN-gamma-inducing factor, is a key mediator of inflammation and host defense responses. In this study, we investigated the regulatory effect of IL-18 on the expression of type I and III collagen genes in dermal fibroblasts. The exposure of human dermal fibroblasts (HDFs) to IL-18 resulted in a reduction of collagen gene expression and production. Also, IL-18 inhibited the fibrogenic cytokine transforming growth factor (TGF)-beta-induced collagen gene expression. Next, to determine the molecular mechanism involved in this regulation, we showed that IL-18-regulated collagen expression was blocked by small interfering RNA (siRNA)-mediated Ets-1 knockdown. Furthermore, we showed that IL-18 induced phosphorylation of extracellular signal-regulated kinase (ERK) within 10 minutes and that the ERK inhibitor PD98059 blocked the inhibitory effect of IL-18. IL-18 also inhibited the production of collagen in systemic sclerosis (SSc) dermal fibroblasts. Our data indicate that IL-18 downregulates collagen production in HDF directly via Ets-1 and the ERK pathway, suggesting that IL-18 may exert antifibrotic activities in dermal fibroblasts.

Long-pulsed 1,064-nm Nd:YAG laser increases the dermal collagen in association with the increased expression of TGF-β.