Allergic contact dermatitis caused by naturally occurring quinones.

Quinones play a major role in allergic contact dermatitis caused by plants. The principal allergens are benzoquinones or naphthoquinones but also compounds, such as catechols and other phenolic or flavonoid compounds, which are bioconverted into ortho-quinones or para-quinones. The high electrophilic reactivity of these compounds toward nucleophilic residues of proteins associated with lipophilic properties may explain that they are strong sensitizers. The more important allergens are reported and their structure-activity relationship is discussed.