Correlation of clinical features and skin barrier function in adolescent and adult patients with atopic dermatitis

Background Xerotic changes in atopic skin are considered to be related to a decrease in the water permeability barrier. Whether abnormal skin barrier function is the main cause of atopic dermatitis (AD) or a secondary change of the disease is still controversial. Noninvasive bioengineering methods, including the measurement of the transepidermal water loss (TEWL) and water capacitance, have been commonly used to evaluate skin barrier function. Aim To evaluate the correlation between the clinical features of each evaluation site (severity of AD) and skin barrier function. Methods TEWL, capacitance, and pH were checked on five evaluation sites: postauricle, forearm, abdomen, thigh, and popliteal fossa. The subjects included 25 patients, both adolescents and adults, with AD and 25 age-matched normal controls. The clinical severity, from 0 (no clinical manifestation) to 3 (severe), was also scored for erythema, induration/papulation, lichenification, and xerosis on each evaluation site of the AD patients. Results Based on the data, we found that the clinical severity score was correlated with TEWL and capacitance in more than one-half of the evaluation sites. Erythema and induration/papulation showed a statistically significant correlation with TEWL in most cases (P < 0.05, four sites). Lichenification and xerosis showed a significant correlation with capacitance in most cases (P < 0.05, four sites). In most cases, severity scoring of the clinical features did not show a significant correlation with skin pH. The patients showed higher TEWL and lower capacitance than normal controls (P < 0.05, all five sites). Conclusions The results of our study suggest that skin barrier function, measured by TEWL and capacitance, and clinical severity show a statistically significant correlation in patients with AD.