title: Alopecia areata: Part 1: pathogenesis, diagnosis, and prognosis.
abstract: OBJECTIVE
  To provide family physicians with a background understanding of the epidemiology, pathogenesis, histology, and clinical approach to the diagnosis of alopecia areata (AA).
  
  
  METHODS
  PubMed was searched for relevant articles regarding the pathogenesis, diagnosis, and prognosis of AA.
  
  
  RESULTS
  Alopecia areata is a form of autoimmune hair loss with a lifetime prevalence of approximately 2%. A personal or family history of concomitant autoimmune disorders, such as vitiligo or thyroid disease, might be noted in a small subset of patients. Diagnosis can often be made clinically, based on the characteristic nonscarring, circular areas of hair loss, with small "exclamation mark" hairs at the periphery in those with early stages of the condition. The diagnosis of more complex cases or unusual presentations can be facilitated by biopsy and histologic examination. The prognosis varies widely, and poor outcomes are associated with an early age of onset, extensive loss, the ophiasis variant, nail changes, a family history, or comorbid autoimmune disorders.
  
  
  CONCLUSIONS
  Alopecia areata is an autoimmune form of hair loss seen regularly in primary care. Family physicians are well placed to identify AA, characterize the severity of disease, and form an appropriate differential diagnosis. Further, they are able educate their patients about the clinical course of AA, as well as the overall prognosis, depending on the patient subtype.
authors.affiliation: Dermatology resident at the University of Ottawa in Ontario.
authors.forename: Frank
authors.initials: F
authors.lastname: Spano
authors.affiliation: Dermatologist, Director of the Women's College Hospital Hair Loss Clinic, and Assistant Professor at the University of Toronto in Ontario. jeffrey.donovan@utoronto.ca.
authors.forename: Jeff C
authors.initials: JC
authors.lastname: Donovan
mesh_terms: D000506:Alopecia Areata / Q000150:complications / Q000175:diagnosis*; D001327:Autoimmune Diseases / Q000150:complications; D003937:Diagnosis, Differential; D006801:Humans; D009260:Nail Diseases / Q000150:complications; D011320:Primary Health Care / Q000379:methods; D011379:Prognosis; D063189:Symptom Assessment / Q000379:methods