[Inhibition of propionibacteria in the sebaceous gland duct using photochemotherapy and 8-methoxypsoralen].

It was shown by in vitro studies that 8-methoxypsoralen (= 8 MOP) alone and UVA irradiation alone produces relatively little inhibition of the growth of Propionibacterium acnes and Propionibacterium granulosum, whereas a combination leads to an intense suppression of bacterial growth. It was further demonstrated by in vivo studies on 14 subjects that local treatment with 8 MOP and UVA significantly reduces the propionibacteria in the pilosebaceous duct. These results afford a possible explanation for the well known favorable effect of photochemotherapy on acne vulgaris. In addition, they contribute to explaining the drier appearance of the skin after photochemotherapy.