Retinoids, methotrexate and cyclosporine.

Acitretin alone is efficient (PASI 90: 40%). In responders, it is the best long-term maintenance treatment (up to 29 years of continuous treatment). The main side effect is its teratogenicity in females. It is necessary to begin retinoid treatment at low doses (10 mg/day), increasing the dose step by step, looking for the maximum well-tolerated dose (usually defined as a mild cheilitis). Doses higher than the highest well-tolerated dose are frequently responsible for the Kobner phenomenon. In children, retinoids are very efficient and nearly always well tolerated, but it seems important to never give more than 0.5 mg/kg/day. Methotrexate is the best treatment for severe psoriasis. Given at low doses once a week, it is a safe, cheap, convenient and efficient treatment, if carefully monitored. The main problem is the possible long-term liver toxicity of methotrexate. The risk is very low in patients not at risk (no liver disease). In these cases, liver biopsies are dangerous and useless. In the other cases, the need for liver biopsy is very rare, decided only by the hepatologist, and should be replaced by FibroTest and FibroScan. The old American guidelines should not be followed, and new guidelines are needed. Cyclosporine at low doses is an outstanding emergency treatment. It was first used as the last possible systemic treatment, but long-term continuous treatments are seldom possible due to alterations in kidney functions. A careful follow-up of kidney functions, with measurement of the glomerular filtration rate after each year of cumulative treatment, is necessary. The cyclosporine dose must be calculated according to the theoretical body weight in obese patients to avoid overdosage. Cyclosporine is mainly used now as a short-term treatment that is very efficient for young people, who find this illness particularly difficult. Cyclosporine is not contraindicated during pregnancy.