title: [Roles of dermoscopy in the diagnosis and differential diagnosis of scalp psoriasis and seborrheic dermatitis].
abstract: OBJECTIVE
  To describe the dermoscopic patterns of scalp psoriasis and seborrheic dermatitis and explore the roles of dermoscopy in their diagnosis and differential diagnosis.
  
  
  METHODS
  A total of 40 patients with scalp psoriasis (n = 20) and seborrheic dermatitis (n = 20) were recruited from Department of Dermatology, Peking Union Medical College Hospital from December 2013 to May 2014. They were examined both dermoscopically and histopathologically. And characteristic dermoscopic features were evaluated. Sensitivity, specificity, positive predictive value and negative predictive value were calculated for predefined dermoscopic criteria in relation to the diagnosis of two diseases.
  
  
  RESULTS
  The most significant dermoscopic features of scalp psoriasis included dotted vessels (10/20, 50%), glomerular vessels (13/20, 65%), red loops (16/20, 80%), hairpin vessels (17/20, 85%), white scales (10/20, 50%) and punctate hemorrhages (12/20, 60%). In contrast, seborrheic dermatitis was characterized by arborizing vessels (16/20, 80%), atypical red vessels (13/20, 65%), featureless areas (20/20, 100%) and honeycomb pigment (9/20, 45%) (all P < 0.05).
  
  
  CONCLUSIONS
  Scalp psoriasis and seborrheic dermatitis have different dermoscopic patterns. Dermoscopy may be valuable for clinical diagnosis and differential diagnosis of scalp psoriasis and seborrheic dermatitis.
authors.affiliation: Department of Dermatology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China.
authors.forename: Chenchen
authors.initials: C
authors.lastname: Xu
authors.affiliation: Department of Dermatology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China.
authors.forename: Dian
authors.initials: D
authors.lastname: Chen
authors.affiliation: Department of Dermatology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China. Email: Liujie04672@pumch.cn.
authors.forename: Jie
authors.initials: J
authors.lastname: Liu
authors.affiliation: Department of Dermatology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China.
authors.forename: Yuehua
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Dermatology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China.
authors.forename: Qiuning
authors.initials: Q
authors.lastname: Sun
mesh_terms: D012628:Dermatitis, Seborrheic; D046169:Dermoscopy; D003937:Diagnosis, Differential; D006801:Humans; D011565:Psoriasis; D012535:Scalp; D012680:Sensitivity and Specificity