Objective: To investigate the effect of a combiphasic oral contraceptive containing ethinylestradiol and desogestrel (combiphasic EE/DSG) on acne, compared with a preparation containing ethinylestradiol and cyproterone acetate (EE35/CPA).

Methods: An open, randomized, group-comparative, multicenter study was carried out, with 172 women randomized to treatment with either combiphasic EE/DSG (25 microg desogestrel and 40 microg ethinylestradiol for 7 days followed by 125 microg desogestrel and 30 microg ethinylestradiol for 15 days) or EE35/CPA (2.0 mg cyproterone acetate and 35 microg ethinylestradiol for 21 days). Assessments were performed at pretreatment and after cycles 3 and 6.

Results: The number of comedones, papules, pustules and nodules significantly decreased in both groups over the 6-month study. Compared with pretreatment (= 100%), the relative numbers of comedones, papules, pustules and nodules at cycle 6 significantly decreased to 37%, 38%, 19% and 12.5% in the combiphasic EE/DSG group and to 24%, 36%, 17% and 1% in the EE35/CPA group, respectively. All reductions were statistically significant (p < or = 0.003) at both cycles 3 and 6, except for nodules at cycle 6 with combiphasic EE/DSG, which probably resulted from differences between the treatment groups at baseline. There were no statistically significant differences between the two treatments. In both groups, the majority of women with severe acne shifted to a less severe acne category.

Conclusions: Combiphasic EE/DSG progressively reduced the number and severity of acne lesions during the six cycles of treatment. The reduction in acne with the combiphasic oral contraceptive was comparable to a preparation containing the antiandrogen cyproterone acetate.