Evaluation of the relation between lipid coat, transepidermal water loss, and skin pH

Objective The epidermis is an epidermal barrier which accumulates lipid substances and participates in skin moisturizing. An evaluation of the epidermal barrier efficiency can be made, among others, by the measurement of the following values: the lipid coat, the transepidermal water loss (TEWL) index, and pH. Materials The study involved 50 Caucasian, healthy women aged 19-35 years (mean 20.56). Methods Measurements were made using Courage & Khazaka Multi Probe Adapter MPA 580: Tewameter TM 300, pH-Meter PH 905, Sebumeter SM 815. The areas of measurements included forehead, nose, left cheek, right cheek, chin, and thigh. Results In the T-zone, the lipid coat was in the range between 0 and 270 lg/cm(2) (mean 128 lg/cm(2)), TEWL between 1 and 55 g/m(2)/h (mean 11.1 g/m(2)/h), and pH 4.0-5.6 (mean 5.39). Lower values of the lipid coat up to 100 lg/cm(2) were accompanied by TEWL greater than 30 g/m(2)/h and less acidic pH of 5.6-9.0. In the U-zone the range of lipid coat was up to 200 lg/cm(2) (mean 65.2 lg/cm(2)), the skin pH remained 4.0-5.6 (mean 5.47), and TEWL was in the range between 1 and 20 g/m(2)/h (mean 8.7 g/m(2)/h). Lower values of the lipid coat up to 100 lg/cm(2) were accompanied by TEWL between 1 and 20 g/m(2)/h and less acidic pH of 5.6-9.0. High values of the lipid coat between 180 and 200 lg/cm(2) were connected with TEWL of 1-15 g/m(2)/h. On the skin of the thigh, we observed a very thin lipid coat -35 lg/cm(2) (mean 5.6 lg/cm(2)), pH (mean 5.37), and TEWL (mean 8.5 g/m(2)/h) were considered by us to be within regular limits. Conclusions In the T-zone, a thinner lipid coat resulted in relatively high TEWL and pH levels changing toward alkaline. In the U-zone, thinner lipid coat was accompanied by lower TEWL and pH changing toward alkaline. We also observed that lower values of lipid coat up to 100 lg/cm(2) were associated with higher pH values ranging toward the basic character pH 5.6-9.0).