TY - CHAP M1 - Book, Section TI - Parapsoriasis and Pityriasis Lichenoides A1 - Schieke, Stefan M. A1 - Wood, Gary S. A2 - Kang, Sewon A2 - Amagai, Masayuki A2 - Bruckner, Anna L. A2 - Enk, Alexander H. A2 - Margolis, David J. A2 - McMichael, Amy J. A2 - Orringer, Jeffrey S. Y1 - 2019 N1 - T2 - Fitzpatrick's Dermatology, 9e AB - AT-A-GLANCEAlso known as parapsoriasis en plaques.Parapsoriasis occurs worldwide and affects mainly adults.Large-plaque parapsoriasis (LPP) and small-plaque parapsoriasis (SPP) are recognized.Large and small “plaque” lesions actually present as flat patches rather than infiltrated plaques.Lesions are chronic and favor non–sun-exposed skin; LPP may be poikilodermatous.Pathology consists of superficial, mostly CD4+ T-cell infiltrate; dominant clonality is more common in LPP than in SPP.LPP appears to exist on a continuum with patch-stage mycosis fungoides (MF) and progresses to overt MF at a rate of approximately 10% per decade.SPP has minimal risk of progression to overt MF in the experience of most experts.Treatment options include topical corticosteroids; ultraviolet B irradiation, and psoralen and ultraviolet A irradiation; excimer laser; and topical cytotoxic drugs. SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/11/06 UR - dermatology.mhmedical.com/content.aspx?aid=1161323249 ER -