Primary and secondary sites of occupational contact dermatitis.

Patterns of distribution of allergic contact dermatitis follow a certain order in time. The disease starts at a given site, most often as a unilateral acrodermatitis and, should it become chronic, spreads locally. The subsequent pattern of distribution varies depending on the primary site and the type--occupational or otherwise--of the disease. In this study data collected two decades ago are confronted with the more recent ones relating to 1055 cases of occupational allergic contact dermatitis. Examination of this material brought to light no essential difference between the older and more recent patterns of distribution of secondary sites. The incidence, however, of certain multiple localizations and of the primary or secondary involvement of the face has diminished.