The effectiveness of low-strength anthralin in psoriasis. A paired comparison study

Recent trends in psoriasis therapy favor using lower-strength anthralins. To assess the effectiveness of a low concentration (0.01%) v a mid concentration (0.1%) of anthralin, combined with UV-B therapy, a prospective double-blind study was undertaken. Nine patients with chronic plaque-type psoriasis involving more than 25% of the total body surface (excluding the scalp) were treated in a paired comparison manner. Patients were examined each day and the degree of erythema, induration, and scale of lesions was recorded for each side of the body. In all nine patients, the side receiving 0.1% anthralin required an average of 10.8 treatment days to achieve the predefined end point: complete flattening of all plaques to palpation. An identical rate of improvement for the 0.01% anthralin-treated side was noted in five of nine patients. The remaining four patients failed to reach the end point on the 0.01% anthralin-treated side even after an average of 15 treatment days.