The differential diagnosis of erythematosquamous diseases remains a diffcult task requiring both clinical and histopathological data to support a diagnosis. The principle reason for diagnostic ambiguity is based on the significant degree of overlap in the overt symptoms
of this class of disease. Histopathological evidence can assist in making a positive diagnosis - but is labor and resource intensive. In order to evaluate the diagnostic veracity of clinical versus histopathological features of erythematosquamous diseases, a comparison of both features classes was evaluated using rough sets. The results indicate that the histopathological feature space provided a much more significant classification rate relative to clinical features. In addition, the results of this preliminary study indicate that only a small subset of the
histopathological feature space is required for maximal classiffication accuracy.