The skin surface microenvironment. Aspects on biophysical conditions and microbiology

Abstract: The influence of skin environmental factors has been investigated in five studies. In the first study, the microbial growth and rash development in diaper dermatitis were studied in order to evaluate a UVB radiation therapy in comparison with a combined antifungal-hydrocortisone cream. The effect of reducing skin environmental pH in experimentally induced Candida lesions was investigated in the second study. The effect of occlusion on vulvar skin temperature, humidity and surface pH, with and without the use of panty liners was investigated in study III and IV, with study IV also including measurements of the skin microflora. In the fifth study, string panties equipped with string panty liners were compared with regular panties with standard panty liners, to evaluate whether there was any difference in their impact on the vulvar skin microenvironment.Diaper dermatitis was susceptible to treatment with UVB therapy, the improvement effect in this study was comparable to the use of antifungal-hydrocortisone cream. Experimentally induced skin reactions caused by C. albicans, were significantly reduced when skin environmental pH was changed from 5.7 to 5.1 (study II). The results were not caused by reduced growth of C. albicans, but might be due to a pH dependence of the virulence of the yeast and/or a modulation of the host s defence capability. The results in study III indicated that vapour-impermeable panty liners increased vulvar temperature, humidity and pH, compared with the use of no liners. However, the use of vapour-permeable (breathable) panty liners kept the microclimate basically at an undisturbed level. Study IV showed that vulvar microclimate and microflora levels were significantly higher during use of a non-breathable panty liner, compared to the use of no liner. The use of a breathable and acidic panty liner resulted in a microclimate and microflora close to the situation without panty liner. However, the numbers of microorganisms were low for all three circumstances (with or without the use of both panty liners) implying no significant microbial risk. The differences in panty and panty liner design in study V (string vs normal), seem to have negligible impact on the vulvar skin microclimate, skin surface pH and microflora. No support was found for the fear that a string panty system would result in higher contamination of vulvar skin with anorectal microflora.It is concluded that changes in skin environmental pH and occlusion are important for changes in skin microflora. A well-balanced skin microenvironment, with respect to temperature, humidity and pH, could be a good preventive approach to avoid skin infections and irritations.