title: Ultrasonographic assessment of nail in psoriatic disease shows a link between onychopathy and distal interphalangeal joint extensor tendon enthesopathy.
abstract: OBJECTIVE
  We compared ultrasonography (US) with the modified nail psoriasis severity index (mNAPSI) to investigate the nail plate, nail matrix and adjacent tendons in subjects with psoriatic nail disease and to test the hypothesis that nail involvement was specifically linked to extensor tendon enthesopathy.
  
  
  METHODS
  86 psoriatic patients (169 nails) and 20 healthy controls (HC) (40 nails) were assessed with both the mNAPSI and US. The thickness of the nail plate, nail matrix region and adjacent extensor tendon were assessed and compared with physical examination findings.
  
  
  RESULTS
  A good agreement between clinical and sonographic nail findings was noted (kappa value = 0.52, p < 0.0001). Entheseal thickening of the extensor tendon on US was more frequent in patients with clinical nail disease compared to patients without clinical nail disease in both psoriasis and psoriatic arthritis (38 vs. 16%, p = 0.03, and 47 vs. 19%, p = 0.008, respectively). Nail thickness, nail matrix and adjacent skin thickness were higher in psoriatic patients compared to HC.
  
  
  CONCLUSIONS
  US and clinical findings show good correlation for the assessment of the nail in psoriatic disease. The demonstration of extensor tendon enthesopathy in both psoriasis and psoriatic arthritis supports the importance of enthesopathy in nail disease pathogenesis whether or not clinical arthritis is present.
authors.affiliation: Unit of Rheumatology, Goztepe Training and Research Hospital, Istanbul Medeniyet University, Istanbul, Turkey.
authors.forename: Sibel Zehra
authors.initials: SZ
authors.lastname: Aydin
authors.forename: Concepción
authors.initials: C
authors.lastname: Castillo-Gallego
authors.forename: Zoe R
authors.initials: ZR
authors.lastname: Ash
authors.forename: Helena
authors.initials: H
authors.lastname: Marzo-Ortega
authors.forename: Paul
authors.initials: P
authors.lastname: Emery
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Wakefield
authors.forename: Miriam
authors.initials: M
authors.lastname: Wittmann
authors.forename: Dennis
authors.initials: D
authors.lastname: McGonagle
mesh_terms: D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D009260:Nail Diseases / Q000000981:diagnostic imaging / Q000209:etiology; D009262:Nails / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D054039:Onycholysis / Q000150:complications / Q000000981:diagnostic imaging*; D011565:Psoriasis / Q000150:complications / Q000000981:diagnostic imaging*; D012216:Rheumatic Diseases / Q000150:complications / Q000000981:diagnostic imaging*; D012720:Severity of Illness Index; D014463:Ultrasonography