ported with either treatment during the study. Three subjects
experienced mild transient itching and one patient experienced
mild to moderate transient itching during two weeks of treatment
with BP (5.3%) emollient foam.
BP is frequently used as either a “wash off” or “leave on” treatment,
both alone or in combination with clindamycin. The primary
mode of action of this non-antibiotic antimicrobial agent is
the reduction of the P. acnes, the organism primarily responsible
for generating inflammatory lesions through. Numerous studies
with various formulations have looked at the in vivo antimicrobial
effect on P. acnes populations of BP and its combinations.
“Leave on” products typically produce a 2.0 logarithm colony
reduction on the face within two weeks, while one BP (6%) wash
formulation produced a 1.5 log reduction after two weeks.
Interestingly, there are no in vivo studies measuring antimicrobial
effects on the trunk for any formulation of BP or antibiotics
such as erythromycin or clindamycin. In this study, the in vivo
antimicrobial effects of a “leave on” BP (5.3%) emollient foam
formulation and BP (8%) wash formulation were compared. A
cross over design permitted comparison of P. acnes reduction
for both agents in each subject and eliminated any variation of
penetration into sebaceous follicles that might occur if parallel
groups had been used.
The “leave on” BP (5.3%) emollient foam produced a 2 log colony
reduction after two weeks of treatment. Interestingly, there
was no reduction in P. acnes on the trunk with the BP 8% wash.
This is very surprising in view of the finding of a 1 log reduction
on the face. The “leave on” product was applied under supervision
in a laboratory setting while the wash product had to be
used at home. Subjects were instructed to thoroughly wash the
areas that had been treated with the foam. The lack of response
in all subjects as opposed to response in some and failure in
others argues against poor adherence. It is unlikely that an entire
panel would have failed to adhere to instructions. However,