DECREASED URINARY HISTAMINE METABOLITE AFTER SUCCESSFUL PUVA TREATMENT OF URTICARIA PIGMENTOSA

[摘要] The effect of PUVA [psoralen plus longwave UV] therapy on pruritus, skin mast cell population and histamine metabolism was studied in 3 patients with urticaria pigmentosa and manifestations of systemic mastocytosis. Relief of itch was concomitant with a significant decrease of a major histamine metabolite, 1-methyl-4-imidazoleacetic acid in urine. The decrease occurred during the first 2 mo. after starting PUVA therapy and was sustained during an observation period of 3 mo. after discontinuation of treatment. At this time a reduction of the number of mast cells was found in skin biopsy specimens. No evidence of acute histmine release in association with PUVA treatment was obtained. This effective new treatment for urticaria pigmentosa reduced histamine turnover in the skin by inhibiting mast cell proliferation.