Primary irritant effect of 3,4,5-trichloropyridazine.

A primary irritant dermatitis to 3,4,5-trichloropyridazine was observed on the hands of a chemist after accidental exposure. Healing was rapid in comparison to a report on 3,4,6-trichloropyridazine toxicity. Prompt treatment with a potent topical corticosteroid, wet soaks, and an oral antihistamine brought resolution within 14 days.