13-cis-Retinoic acid and tetracycline versus 13-cis-retinoic acid alone in the treatment of nodulocystic acne.

A comparative clinical study on therapy of nodulocystic acne with 13-cis-retinoic acid was performed in 32 patients. 20 patients were treated with a dose of 1 mg/kg body weight daily, and 12 with a combined therapy: 0.25 mg/kg/day 13-cis-retinoic acid and 0.5 g of tetracycline daily. In both groups the therapy was carried out for 16 weeks. The effect of the combined therapy within 4 months was favourable in 75% of the cases versus 100% in the group treated with larger doses of 13-cis-retinoic acid. Thus, the time needed for clearing was longer in some patients (up to 6 months). However, the incidence of side effects was considerably lower in the group of combined therapy. In acne fulminans 13-cis-retinoic acid alone is not effective and should be combined with corticosteroids.