title: Extraspinal enthesopathy caused by isotretinoin therapy.
abstract: OBJECTIVE
  To discuss a case of diffuse peripheral enthesopathy in a patient previously treated with long-term isotretinoin (Accutane) for severe acne.
  
  
  METHODS
  A 47-year old man with 1 month history of moderate neck and right upper extremity pain, with hypoesthesia of the right second and third fingers. Palpable bony prominences around multiple superficial joints were noted on physical examination, raising the initial question of osteochondromatosis. Multiple active acne pustules were noted. A limited skeletal survey demonstrated diffuse peripheral enthesophyte formation and hyperostoses, resembling those of diffuse idiopathic skeletal hyperostosis, but without accompanying spinal changes. A history of long-term Accutane therapy was then elicited.
  
  
  RESULTS
  The enthesopathy was believed to represent an asymptomatic, longstanding, iatrogenically induced abnormality. No specific therapy or follow-up was indicated. The patient had discontinued use of Accutane years ago. Cervical symptoms improved with four sessions of cervical traction and nonsteroidal anti-inflammatory medications, but upper extremity symptoms were refractory.
  
  
  CONCLUSIONS
  Accutane-induced enthesopathy should be considered in individuals with correlating radiologic and clinical features and history of retinoic acid therapy for acne. This should be a diagnosis by exclusion, after eliminating other potential causes of peripheral enthesopathy, particularly diffuse idiopathic skeletal hyperostosis, seronegative spondylarthropathy, and fluorosis.
authors.affiliation: Department of Radiology, Northwestern College of Chiropractic, Bloomington, MN 55431-1599, USA.
authors.forename: J R
authors.initials: JR
authors.lastname: Brandt
authors.forename: T J
authors.initials: TJ
authors.lastname: Mick
mesh_terms: D000152:Acne Vulgaris / Q000188:drug therapy; D003937:Diagnosis, Differential; D006801:Humans; D015474:Isotretinoin / Q000009:adverse effects*; D007641:Keratolytic Agents / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D019547:Neck Pain / Q000209:etiology; D011859:Radiography; D012216:Rheumatic Diseases / Q000139:chemically induced* / Q000175:diagnosis* / Q000000981:diagnostic imaging
chemical_list: D007641:Keratolytic Agents; D015474:Isotretinoin