Clinical review: thioureas and allergic contact dermatitis.

Thioureas are an uncommon underrecognized cause of allergic contact dermatitis (ACD). This article presents the findings in 3 individuals with ACD to thioureas and reviews the medical literature concerning thiourea-induced ACD. Thioureas are often the allergenic sources in ACD involving high-grade rubber products made of neoprene. Standard patch test series and rubber allergen patch test series usually do not contain thiourea allergens and will fail to diagnose these causes of ACD. Thioureas--most notably diethylthiourea, dibutylthiourea, and diphenylthiourea--should be considered in individuals with potential rubber allergy who fail to react to antigens in the standard allergen patch test tray.