title: Pityriasis rubra pilaris: the clinical context of acantholysis and other histologic features.
abstract: BACKGROUND
  Acantholysis has been described in biopsies of pityriasis rubra pilaris (PRP), but this has not been emphasized in the dermatology literature. It is helpful for dermatologists to associate acantholysis with PRP in the correct clinical setting.
  
  
  OBJECTIVE
  This study aims to further elucidate the clinical context and associated histologic features of acantholysis in PRP.
  
  
  METHODS
  Eight cases of PRP with acantholysis, 16 other cases of PRP, 26 cases of psoriasis, and 17 cases of erythroderma of different causes were studied in an academic setting.
  
  
  RESULTS
  The presence of acantholysis initially confounded the diagnosis in two cases of PRP. Acantholysis was focal or extensive and resembled Darier's disease, Hailey-Hailey disease, or pemphigus vulgaris. Acantholysis was seen in biopsies from early, isolated papulosquamous lesions from the trunk as well as from erythroderma. By comparison, 26 cases of psoriasis and 17 cases of erythroderma showed only focal acantholysis in two cases of erythroderma.
  
  
  CONCLUSIONS
  Acantholysis is a histologic feature of PRP and can serve as a histologic clue to the diagnosis of PRP before the onset of erythroderma. Eosinophils and/or a lichenoid infiltrate may also be evident.
authors.affiliation: Department of Dermatology, Yale University School of Medicine, New Haven, CT, USA. christine.ko@yale.edu
authors.forename: Christine J
authors.initials: CJ
authors.lastname: Ko
authors.forename: Leonard M
authors.initials: LM
authors.lastname: Milstone
authors.forename: Jaehyuk
authors.initials: J
authors.lastname: Choi
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: McNiff
mesh_terms: D000051:Acantholysis / Q000473:pathology*; D000328:Adult; D000368:Aged; D001706:Biopsy; D007644:Darier Disease / Q000473:pathology; D003873:Dermatitis, Exfoliative / Q000473:pathology; D003937:Diagnosis, Differential; D004804:Eosinophils / Q000473:pathology; D005260:Female; D006801:Humans; D017512:Lichenoid Eruptions / Q000473:pathology; D008297:Male; D008875:Middle Aged; D010392:Pemphigus / Q000473:pathology; D016506:Pemphigus, Benign Familial / Q000473:pathology; D010916:Pityriasis Rubra Pilaris / Q000473:pathology*; D011565:Psoriasis / Q000473:pathology