Effect of 13-cis-retinoic acid on sebum production and Propionibacterium acnes in severe nodulocystic acne.

Ten patients treated with 13-cis-retinoic acid demonstrated a 70% reduction in sebum excretion on the forehead and cheek. An average reduction of 66% occurred in the 1st month, slowly increased to 70% by the 3rd month, and then remained constant for the final 2 months of therapy. Concomitant with this sebum excretion reduction was a fall in the number of Propionibacterium acnes recovered from both sites. Pretreatment values of 10(4) P. acnes per square centimeter (cm2) fell to 10(3) per cm2 after 1 month and 10(2) after 9 months of therapy. P. acnes was not recovered from six of the ten subjects in the following 3 months and only at levels of 10(2) per cm2 in three subjects. One subject's P. acnes level was reduced to only 10(4) per cm2. Following discontinuation of therapy, sebum levels and P. acnes counts showed a trend to recover to pretreatment levels within 2 months.