Background: We report on IgE-mediated allergy in a worker caused by Tribolium confusum (confused¯our beetle). These beetles lived in the``old''¯our to which he was exposed in his work. Case report: A 35-year-old, nonatopic mechanic in a rye crispbread factory developed rhinitis, conjunctivitis, and asthmatic symptoms, as well as urticaria on his wrists, lower arms, hands, neck, and face, during the maintenance and repair of machines contaminated by¯our. This¯our had been in and on the machines for a long time, and it contained small beetles. The patient did not suffer any symptoms when handling fresh, clean¯our. Results: Skin prick tests with standard environmental allergens, storage mites, enzymes,¯ours, and molds were negative. A prick test with¯our from the machines gave a 10-mm reaction. An open application of the same¯our caused urticarial whealing on the exposed skin. Prick tests with fresh¯our from the factory were negative. A prick test with minced T. confusum from the¯our in the machines gave a 7-mm reaction. Histamine hydrochloride 10 mg/ml gave a 7-mm reaction. Speci®c serum IgE antibodies to T. confusum were elevated at 17.2 kU/l. Prick tests with the¯our from the machines were negative in ®ve control patients. Conclusions: The patient had occupational contact urticaria, rhinitis, conjunctivitis, and asthmatic symptoms from exposure to¯our. His symptoms were caused by immediate allergy to the beetle T. confusum. Immediate allergy to this beetle has rarely been reported in connection with respiratory symptoms, but it may be more common. Contact urticaria from this source has not been reported before.

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