Parapsoriasis and related conditions.

Classification of parapsoriases is revised into a simple practical table. Pityriasis lichenoides (guttate parapsoriasis) is not a type of parapsoriasis. The clinical features of small patch and large plaque parapsoriasis are described in detail. Six clinical varieties of large plaque parapsoriasis and three clinical varieties of exfoliative dermatitis including Sézary syndrome have been clearly recognized as distinctive categories. Histopathology is useful for the diagnosis of parapsoriasis and mycosis fungoides. Sézary cell count is not significant for the diagnosis of Sézary syndrome.