Skin Surface pH in Acne Vulgaris: Insights from an Observational Study and Review of the Literature.

Recurrent and chronic course of acne vulgaris, despite effect-proven therapies, point to an underfocused aspect in its pathogenesis and management. This study aims to assess in subjects with and without acne, the skin surface pH, a parameter that cumulatively represents functioning of various units of skin, including the barrier. A total of 200 patients with acne and 200 age- and sex-matched controls were included. Under basal conditions, facial skin pH was derived from five sites using a skin pH-meter. The relation between skin pH and acne was evaluated according to sex. There were more subjects with normal skin pH in the control group compared to the case group, and the majority of acne occurrences in the case group were related to high skin pH (=0.000). Mean pH among cases was higher than normal reference value (pH 4.5-5.5 for women, 4-5.5 for men) and that of controls (<0.001). No significant association was observed between sex and skin pH in either cases or controls (>0.05). Increased facial skin pH in patients with acne at basal conditions mirrors a chronic state of stratum corneum instability, which could be predisposing individuals to acne occurrence and/or recurrences. It could possibly be a common domain via which the classical pathomechanisms might be acting in acne. Integrating measures that maintain stratum corneum pH during therapy might prove worthwhile.