Biomonitoring of hand and forearm transepidermal water loss and skin PH among nursing apprentices

Background: Measurements of transepidermal water loss (TEWL) and stratum corneum (SC) pH can help indicate work-related skin barrier damage, but sensitivity to confounding personal and ambient factors limits their potential as biomonitoring tools. Objectives: To evaluate the difference between hand and forearm skin barrier conditions as a tool for early recognition of workers with occupational contact dermatitis. Participants and Methods: The participants were nursing apprentices (N = 238, median age 19 years) from Zagreb, Croatia. They filled out a questionnaire based on the Nordic Occupational Skin Questionnaire, underwent a clinical examination of skin on the hands, and were evaluated for their TEWL and SC pH on the dorsum of the hand and volar part of the forearm. Results: We found that the difference between hand and forearm TEWL values (Delta TEWL) Delta TEWL) greater than 7 g/m(2)/h, or >50%, or the difference in SC Delta pH >0.50, predicted visible skin changes found on clinical examination. However, only the association with Delta pH >0.50 retained statistical significance when controlled for sex, age, ambient temperature, and relative humidity in a multiple regression model. Conclusions: The difference between hand and forearm SC pH values is suggested as a reliable biomonitoring tool in recognition of damaged skin barrier conditions in occupational settings.