Contact allergy to styrene and related chemicals.

One patient, sensitive to styrene, cross-reacted at patch testing to 2-,3-and 4-vinyltoluene (2-,3-and 4-methylstyrene) and to the metabolites styrene epoxide and 4-vinylphenol (4-hydroxy-styrene). It is assumed that styrene is a prohapten metabolized in the skin by aryl hydrocarbon hydroxylase (AHH) to styrene epoxide acting as the true hapten. Styrene occurs in nature and as a synthetic product. Vinyltoluenes (methylstyrenes) occur as synthetic products in plastics. 4-vinylphenol (4-hydroxystyrene) occurs frequently in different ciders, wines, foods and berries, e.g. cloudberry.