This information is provided by the National Institutes of Health (NIH) Genetic and Rare Diseases Information Center (GARD).
Parapsoriasis describes a group of skin diseases that can be characterized by scaly patches or slightly elevated papules and/or plaques (red, scaly patches) that have a resemblance to psoriasis. However, this description includes several inflammatory cutaneous diseases that are unrelated with respect to pathogenesis, histopathology, and response to treatment. Because of the variation in clinical presentation and a lack of a specific diagnostic finding on histopathology, a uniformly accepted definition of parapsoriasis remains lacking.
There are 2 general forms: a small plaque type, which is usually benign, and a large plaque type, which is a precursor of cutaneous T-cell lymphoma (CTCL). Treatment of small plaque parapsoriasis is unnecessary but can include emollients, topical tar preparations or corticosteroids, and/or phototherapy. Treatment of large plaque parapsoriasis is phototherapy or topical corticosteroids.
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