[Differentiation of lupus erythematosus and lymphocytic infiltration]

Lymphocytic infiltration and lupus erythematosus have many features in common. The main distinguishing factor is the lack of epidermal involvement in lymphocytic infiltration, as compared to the frequent presence of epidermal changes in discoid lupus erythematosus. Other factors claimed to differentiate between both conditions are lack of antinuclear antibodies, negative immunofluorescence findings, and the more frequent presence of plasmacytoid monocytes in lymphocytic infiltration. To evaluate the significance of those findings, we studied cases of lymphocytic infiltration and lupus erythematosus with and without epidermal changes, using the same set of clinical, histopathological, and immunological criteria. No differences were found between lymphocytic infiltrates in cases with and without epidermal involvement. Based on those findings, lymphocytic infiltration seems to be a morphological variant of lupus erythematosus, rather than a distinct entity.