Showering reduces atopic dermatitis in elementary school students

ARTICLE

Auteur(s) : Hiroyuki Murota, Aya Takahashi, Megumi Nishioka, Saki Matsui, Mika Terao, Shun Kitaba, Ichiro Katayama

Department of Dermatology, Osaka University, 2-2, Yamadaoka, 565-0871 Suita, Japan

Sweat is thought to exacerbate the symptoms of atopic dermatitis (AD) [1, 2]. It is known that the pH of sweat and skin surfaces increases with time [3]; thus, old sweat might cause skin barrier dysfunction and promote infection. Such susceptibility to environmental factors and infection are considered clinical features of AD [4]. Therefore, we hypothesized that rinsing skin surfaces by showering might reduce the severity of atopic dermatitis by decreasing bacteria on the skin surface. It has been reported that showering at school reduces the severity of AD [5, 6]; however, the mechanism has not been determined. We evaluated the effect of showering on skin barrier function and the number of bacteria on affected skin, in elementary school students with AD.

The effects of showering were measured over a 4-week period in September with the approval of the institutional review board. Study subjects (n = 11) were chosen by the presence of AD, and the study was carried out with the consent of a parent or guardian. Students were instructed to rinse skin with a shower or running water during a 20-minute break between the second and third classes every weekday, and to avoid treatment changes during this period. The severity of AD was evaluated using the eczema area and severity index (EASI), as determined by three dermatologists simultaneously. For assessment of the skin barrier function, trans-epidermal water loss (TEWL) and water retaining capacity were evaluated. Estimates of body surface area (BSA) involvement were obtained from the objective severity assessment via AD scoring software. Staphylococcus aureus (S. aureus) was collected using sterilized filter paper (4 × 4 cm) moistened with sterilized saline and placed against the skin (cubital fossa). The filter paper then was put onto 4 cm of selective medium for S. aureus. After incubation at 37 °C for 24 hours, the number of colonies per plate was counted. Determination of shower efficacy was made by dermatologists who visited the school 2 and 4 weeks after the initiation and 2 weeks after the termination of the intervention.

A significant decrease in EASI score was observed at 2 and 4 weeks after the intervention compared with before initiation of the intervention (figure 1A). Disappearance of the eczematous lesion was greatly visible, and a significant decrease in the affected area was observed 4 weeks after initiation and 2 weeks after termination (figure 1B). Unfortunately, the results of TEWL and water retaining capacity showed no specific trend, most likely due to the fact that students participated in athletic activities (causing sweating) just prior to assessment (not shown).

Four weeks after initiation and 2 weeks after termination, a significant decrease in the number of S. aureus was observed relative to before initiation of this intervention (figure 1C).

In conclusion, although there are limitations with regard to the number of cases evaluated, study duration, and lack of controlled comparison, we found that showering the skin surface while at school prevented the exacerbation of AD. This favorable effect of showering was produced by a standard shower facility and tap water, and might be mediated by decreasing skin surface bacteria. Of course, optimization of conditions for showering/rinsing in terms of adequate water temperature and the time required for showering should be established in the future.

Acknowledgements

References

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