TY - CHAP M1 - Book, Section TI - Pityriasis Rubra Pilaris A1 - Schäkel, Knut 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. PY - 2019 T2 - Fitzpatrick's Dermatology, 9e AB - AT-A-GLANCEA rare inflammatory papulosquamous dermatosis, often self-limiting within a few years.The disease is subclassified into 6 types, including both hereditary and acquired forms.The hereditary form of pityriasis rubra pilaris is linked to CARD14 gain-of-function mutations, the cause of the acquired forms is unknown.Typical features are follicular hyperkeratotic papules that coalesce into scaly, reddish-orange–colored plaques, which may progress to erythroderma with well-demarcated islands of normal skin.Distinguishing pityriasis rubra pilaris from psoriasis poses a major diagnostic challenge, particularly in the early phases of the disease.Histopathologic examination reveals hyperkeratosis, alternating parakeratosis and orthokeratosis in a checkerboard pattern, with focal acantholytic dyskeratosis.The most successful treatment options are systemic retinoids, methotrexate, and photochemotherapy (psoralen and ultraviolet A). In recent years, biologics blocking tumor necrosis factor-α and interleukins-12 and -12p40 were shown to be effective. SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/03/29 UR - dermatology.mhmedical.com/content.aspx?aid=1161323165 ER -