Allergic contact dermatitis from color film developers: clinical and histologic features.

We evaluated two patients with allergic contact dermatitis that resulted from exposure to color film developers. A lichenoid eruption developed in one patient, whereas an eruption more characteristic of an acute spongiotic dermatitis developed in the second patient. Histologic findings in the first case were those of a "lichenoid dermatitis" but with features distinct from classic lichen planus. The biopsy specimens from the second patient showed a subacute spongiotic process with a bandlike infiltrate suggestive of an evolving lichenoid process. Contact allergy to color developers may result in eruptions similar to lichen planus. This process appears to evolve from an acute spongiotic dermatitis in its early phase to a lichenoid dermatitis in fully developed and more chronic forms. Although the histologic features are those of a "lichenoid" dermatitis, some features, such as the presence of spongiosis, eosinophils, and a less intense inflammatory infiltrate, may enable distinction between lichenoid allergic contact dermatitis and true lichen planus. In addition, clinicopathologic correlation with patch test results should permit accurate diagnosis in most cases.