Parapsoriasis is a term which encompasses a number of differing pathologic states clinically manifesting chronic recalcitrant erythematous scaling lesions. Although these various diseases have some similar clinical and histopathological features, they are obviously quite different from the standpoint of malignant potential and prognosis. The classification suggested herein has been developed in an attempt to resolve the existing confusion and to offer a simplified approach to the study of a complex problem.