Effect of betamethasone valerate on the normal human facial skin flora.

Eighteen volunteers were randomly divided into two groups and allocated either an active corticosteroid preparation (Betamethasone valerate) or the basal formulation only (placebo). The cream was applied to the face twice daily for one month. The treated area was sampled by the scrub-wash method immediately before treatment began and after 2 and 4 weeks, and microorganisms were enumerated and identified. Application of either cream produced a very slight increase (less than or equal to 0.5 log cycle) in the skin flora during the first 2 weeks of treatment. There were no significant differences in the changes occurring between volunteers treated with placebo and those on the steroid formulation. The results are discussed in relation to theories of pathogenesis of perioral dermatitis and steroid acne.