Content » Vol 67, Issue 1

Investigative Report

Influence of repeated washings with soap and synthetic detergents on pH and resident flora of the skin of forehead and forearm. Results of a cross-over trial in health probationers.

Korting HC, Kober M, Mueller M, Braun-Falco O
DOI: 10.2340/00015555674147


Ten healthy individuals washed their forehead and forearm twice a day over consecutive periods of four weeks with soap and synthetic detergents or vice versa (cross-over design). In general the pH values were higher during the period when soap was applied (the mean pH differed by 0.3 units, p less than 0.01). As a rule the counts of coagulase-negative staphylococci were not much altered. The number of propionibacteria, however, was markedly higher when soap was used (p = 0.02 and 0.01 resp.). At the forehead there was a clear correlation between bacterial counts and skin pH both with propionibacteria (0.56, p less than 0.001) and staphylococci (0.51, p less than 0.001). At the forearm only the former proved true (0.24, p less than 0.05). Thus the skin pH seems to be open to long-standing changes according to the preferred washing habits which may also be of major influence on the composition of the cutaneous bacterial flora.


Supplementary content


Not logged in! You need to login/create an account to comment on articles. Click here to login/create an account.