To assess the effects of tin (Sn)-protoporphyrin (a synthetic haem analogue) in conjunction with long wave length ultraviolet light (UVA) radiation in psoriasis 10 patients, 9 of whom were substantially or completely unresponsive to other forms of therapy, received 2·0 μmol/kg bodyweight of Sn-protoporphyrin for 1 day followed by UVA light treatment for 21 days. The average starting UVA dose was 5·6 (SD 2·0) J/cm2, and the average cumulative UVA dose was 98·3 (35·1) J/cm2. Severity of psoriatic plaques, scored clinically on a scale of 0-3 for erythema, scaling, and induration, fell from a mean score of 7·9 at the start of the study to 3·6 at the end. Psoriatic lesions were improved in all patients and the effect was striking in some. The responses lasted throughout the three weeks of the study and no deleterious side-effects of the treatment were noted. Clinical follow-up for three months showed no rebound in disease activity. Sn-protoporphyrin with conventional UVA light may be useful in the treatment of psoriasis.
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