dermatologic disorders
Parapsoriasis
Key Points
Parapsoriasis is an etiologically heterogeneous group of disorders that tend to have a similar appearance—thin, scaling, dull, pink patches and plaques with a slightly atrophic or wrinkled appearance. Parapsoriasis with plaques < 5 cm in diameter is usually benign; parapsoriasis with plaques>5 cm in diameter transforms into cutaneous T-cell lymphoma in about 10% of patients per decade. Diagnose based on clinical appearance; biopsy and other tests may be necessary to rule out cutaneous T-cell lymphoma. Treat small-plaque parapsoriasis symptomatically and large-plaque parapsoriasis with phototherapy or topical corticosteroids. 