The effect of grenz rays on psoriasis lesions of the scalp: a double blind bilateral trial.

Sixteen patients with symmetrical psoriasis lesions of the scalp were treated with grenz rays. In a double blind fashion, one side of the scalp was irradiated with 4 Gy of grenz rays applied on 6 occasions at intervals of 1 week, and the other side of the scalp was given placebo treatment. The patients were seen before and after X-ray therapy. A significantly (P less than 0.0001) better therapeutic result was recorded on the side of the scalp which had received active grenz ray therapy. In 14 of the 16 patients there was complete healing on the grenz ray-treated side after 6 wk of treatment. Nine patients were still free of lesions of the scalp 3 months after the start of the grenz ray therapy.