Distribution of skin surface pH on the forehead and cheek of adults.

The skin surface pH on the forehead and cheek of 574 men and women aged 18-95 was measured. No differences were found between men and women regarding forehead and cheek pH distribution. The group over the age of 80 showed higher pH values on both the forehead and the cheek. In 89% of the subjects measured, the skin surface pH on the cheek was higher than that on the forehead. The central 90%, i.e., the "representative range", for the population below the age of 80 is between 4.0-5.5 on the forehead and between 4.2-5.9 on the cheek.