TY - CHAP M1 - Book, Section TI - Pityriasis Rosea A1 - Clark, Matthew A1 - Gudjonsson, Johann E. 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-GLANCECommon self-limited papulosquamous eruption typically lasting 5 to 8 weeks.Occurs worldwide in all races and age groups, with peak incidence between the ages of 10 and 35 years.Classically begins as an isolated 3- to 5-cm oval plaque on the trunk with a collarette of fine scale just inside the periphery, which plaque is called a herald patch.This is followed by a secondary eruption of similar appearing but smaller lesions on the trunk and proximal extremities, usually with their long axis along the lines of cleavage.Many atypical variants exist in contrast to the pattern described above.Pityriasis rosea can have associated systemic symptoms and pruritus, but many cases are asymptomatic.Etiology is unknown, but it is thought to be a viral exanthem most likely related to infection or reactivation of human herpesvirus (HHV)-6 and/or HHV-7.Usually only supportive treatment and reassurance is needed, but for severe cases acyclovir may hasten recovery and lessen symptoms. SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/10/14 UR - accessmedicine.mhmedical.com/content.aspx?aid=1161328461 ER -