Does UV-A potentiate 'short contact' dithranol therapy?

The effect of ultraviolet-A (UV-A) irradiation in combination with 'short contact' dithranol treatment was studied in ten patients with chronic plaque psoriasis. Increasing concentrations of dithranol were applied daily to the psoriatic plaques on both sides of the body. One side was irradiated with UV-A daily. There was no difference in the rate of clearance between the two sides. The effectiveness of 'short contact' dithranol was confirmed.