[Curling and kinking of hair caused by etretinate].

In two female psoriasis patients, curling and kinking of the scalp hair developed subsequent to a long-term etretinate therapy. Scanning electron microscopic examination of kinking hair revealed twists with sharp-edged defects and splitting of the cuticle cells in several hairshafts. The quantitative determination of the mechanical parameters of these hairs using a computerized system revealed statistically significant changes from the pattern in the scalp hair of untreated psoriasis patients. This finding suggests etretinate-induced alteration of the expression of the psoriatic phenotype in the keratin composition of hair in psoriasis patients.