A study by Borok in 1990 suggests that etretinate may be superior to isotretinoin. Since that time, etretinate has been taken off of the market due to its prolonged half-life and risk of teratogenicity. It has been replaced by acitretin, which still has risks of teratogenicity, but a much shorter half-life. Clinical improvement can be expected within 4-6 months. Etretinate is main metabolite and has demonstrated clinical effects close to those seen with etretinate.
Mechanism of action is unknown.
There have been reports of success with the use of methotrexate. Follow the same guidelines as for use of methotrexate in psoriasis. Improvement may be seen in 6 wk and complete response after 3-4 months. Relapse may occur upon discontinuation of medication. Serious adverse effects include hepatic fibrosis, bone marrow suppression and pneumonitis.