OCCUPATIONAL ALLERGIC CONTACT-DERMATITIS CAUSED BY THIOUREA COMPOUNDS

Thiourea compounds are mainly used as accelerators in the rubber indus try, but also in other industries, e.g., as antioxidants in the graphi cs industry. Thiourea compounds may provoke allergic contact dermatiti s, although the number of reported cases is relatively low. During 198 5-1991, we had 5 patients with allergic patch test reactions caused by thiourea compounds. 1 of our patients had to use a knee brace after a n occupational accident. He developed allergic contact dermatitis caus ed by the knee brace, probably because he had become sensitized to die thylthiourea. 2 patients were probably sensitized by diphenylthiourea in neoprene gloves. A florist had an allergic patch test reaction to d iphenylthiourea and might have been sensitized by fungicides or pestic ides, which break down into thioureas. It is often difficult, however, to detect the source of thiourea compound sensitization. If the patie nt has contact dermatitis and has been exposed to products that may co ntain thiourea compounds (or compounds that break down into thiourea c ompounds), such as rubber, PVC plastic or adhesive, diazo paper, paint s or glue remover, anticorrosive agents, fungicides or pesticides, pat ch testing with a series of thiourea compounds needs to be performed. If patch testing with thiourea compounds is not performed, allergic co ntact dermatitis caused by thiourea compounds is not likely to be diag nosed.