Neoprene.

Neoprene is a synthetic rubber with many common uses, including use in shoe insoles and adhesives, orthopedic braces, and gloves. Many cases of type IV hypersensitivity from neoprene contact have been reported. Thioureas, the most commonly used vulcanization accelerators in the manufacture of neoprene, are responsible for the majority of these cases. However, thioureas are not included in the TRUE Test whereas the North American Contact Dermatitis Group standard tray contains only mixed dialkyl thioureas. Since most data indicate that many cases will be missed when only mixed dialkyl thioureas are used for screening, a more complete thiourea panel should be used when neoprene hypersensitivity is suspected.