Dosing to rash?--The role of erlotinib metabolic ratio from patient serum in the search of predictive biomarkers for EGFR inhibitor-mediated skin rash.
BACKGROUND Skin pH is one of the important physiological parameters of the skin. Changes in the pH play a role in the pathogenesis of several skin diseases, including acne. PURPOSE To assess the correlation between the pH and the age, and between the pH and the development of acne lesions, in a large acne patients group. We also evaluated the difference between the genders. METHODS A total of 540 patients clinically diagnosed with acne vulgaris were included. The clinical digital photographs were taken, and the acne lesions were counted. The pH was measured, using the skin-pH-meter . Area-weighted pH was calculated and statistical analysis was performed, according to age and gender. RESULTS The female had higher pH than the male acne patients. The T-zone had higher pH than that of the U-zone. In female acne patients, age and the area-weight pH showed a positive correlation. Male acne patients had more inflammatory lesions. And U-zone showed more acne lesions than T-zone. There are negative correlations between the area-weight pH and the number of acne lesions, in the T-zone of the female acne patients and positive correlation at the inflammatory lesions on the T-zone of male acne patients. CONCLUSIONS This is the first study to evaluate the correlations between pH, age, gender, and acne development in a large acne patients group using an objective, bioengineering method within the viewpoint of skin pH. We could expect that there are gender differences in the correlation between pH, age, and acne development. From this result, we could provide a clue to the treatment of acne, that maintaining the pH balance according to the difference of gender and age is an essential consideration.