title: Unusual forms of alopecia areata in a Trichology Unit.
abstract: BACKGROUND
  Alopecia areata (AA) occurs with the apparition of asyntomatic non inflamatory alopecia plaques without scars. We distinguish several variants which are divided into two groups: typical forms (AA in single or multiple plaques) and atypical forms (by its presentation, evolution or paradoxical regrowth).
  We describe the cases of AA treated in our Trichology Unit between January 2000 and December 2011.
  
  
  RESULTS
  We obtained 488 cases of AA. 114 (23.36%) were unusual form of AA or had paradoxical regrowth. The most common unusual form of AA was sisaipho type (7.37%), followed by AA for black and blonde hair (5.32%), atypical diffuse forms (4.30%), androgenetic alopecia type and (3.89%) and AA rectangular occipital (0.68%). Furthermore, we found nine cases of paradoxical regrowth (1.84%).
  
  
  CONCLUSIONS
  Atypical variants of AA in our series are less than 25% of all cases, although it should be noted that since it is a specialized unit, we may be making a selection bias to be more difficult to diagnose cases or poor outcome.
authors.affiliation: Department of Dermatology, Virgen Macarena University Hospital, Seville, Spain.
authors.forename: C M
authors.initials: CM
authors.lastname: Priego-Recio
authors.forename: A
authors.initials: A
authors.lastname: Rodríguez-Pichardo
authors.forename: F M
authors.initials: FM
authors.lastname: Camacho-Martínez
mesh_terms: D000328:Adult; D000506:Alopecia Areata / Q000145:classification* / Q000175:diagnosis; D046169:Dermoscopy / Q000379:methods; D003937:Diagnosis, Differential; D005260:Female; D005500:Follow-Up Studies; D006197:Hair / Q000254:growth & development; D006801:Humans; D008297:Male; D011379:Prognosis; D012189:Retrospective Studies; D012720:Severity of Illness Index