Reduced sex hormone binding globulin and derived free testosterone levels in women with severe acne.

Reduced circulating sex hormone binding globulin (SHBG) levels were found in 54% of a group of women with moderate to severe acne and in 60% of another group of twenty-three women who had acne complicated by hirsutism and/or irregular menstrual cycles. The concentrations of SHBG for the women with acne alone (mean 48 +/- 24 nmol/l) and for those with acne and hirsutes (mean 39 +/- 18 nmol/l) were compared with the SHBG concentrations of fifteen unaffected women with normal menstrual cycles (mean 70 +/- 19 nmol/l). The differences in mean SHBG values for both groups of women with acne were significant (P less than 0.001) on comparison with the mean for the unaffected women. Twenty-nine per cent of the women with acne had elevated testosterone values (mean testosterone concentration for the group 1.5 +/- 0.3 nmol/l) and 41% had elevated 'derived' free testosterone levels (mean 21 +/- 6 pmol/l). Of the women with acne and hirsutes 65% had elevated plasma testosterone levels (mean 2.1 +/- 0.6 nmol/l) and 89% had elevated free testosterone concentrations (mean 31 +/- 10 pmol/l). The mean values for testosterone and free testosterone in the plasma of unaffected women (mean testosterone concentration 1.1 +/- 0.3 nmol/l and free testosterone 13 +/- 4 pmol/l) were significantly lower than in women with acne alone (P less than 0.01 and P less than 0.001) and in women with acne and hirsutism (P less than 0.001). This study indicates that a deficiency in SHBG and an elevation in 'derived' free testosterone is a frequent finding in women with severe acne and may be a significant factor in the aetiology and/or perpetuation of this condition.