Occupational contact urticaria to cannabis sativa.

Cannabis allergy is not commonly reported, perhaps due to the legal status of cannabis use and the difficulties of obtaining permission to test it. We report 3 cases of work-related cannabis allergy with features suggestive of a dermatitis, rather than a contact urticaria. Only prick tests were able to confirm the diagnosis. Identification of the cause of the rash was essential to direct work re-deployment.