Contact urticaria and asthma from denatonium benzoate (Bitrex)

A 30-year-old male developed asthma and pruritus after using an insecticidal spray (Pyrex). The same symptoms appeared with an alcoholic skin disinfectant (M-sprit) and other spirituous preparations denaturated with denatonium benzoate (Bitrex). An open epicutaneous test (20 min) showed wheal and erythema to Pyrex, M-sprit and Bitrex diluted to 2 x 10(-6) mg 1-1. It is deduced that the contact urticaria elicited from denatonium benzoate was caused by an immunologic mechanism of the immediate hypersensitivity type.