title: Distinguishing androgenetic alopecia from chronic telogen effluvium when associated in the same patient: a simple noninvasive method.
abstract: BACKGROUND
  Distinguishing chronic telogen effluvium (CTE) from androgenetic alopecia (AGA) may be difficult especially when associated in the same patient.
  
  
  METHODS
  One hundred consecutive patients with hair loss who were clinically diagnosed as having CTE, AGA, AGA + CTE, or remitting CTE. Patients washed their hair in the sink in a standardized way. All shed hairs were counted and divided "blindly" into 5 cm or longer, intermediate length (>3 to <5 cm), and 3 cm or shorter. The latter were considered telogen vellus hairs, and patients having at least 10% of them were classified as having AGA. We assumed that patients shedding 200 hairs or more had CTE. The kappa statistic revealed, however, that the best concordance between clinical and numerical diagnosis (kappa = 0.527) was obtained by setting the cutoff shedding value at 100 hairs or more. Of the 100 patients, 18 with 10% or more of hairs that were 3 cm or shorter and who shed fewer than 100 hairs were diagnosed as having AGA; 34 with fewer than 10% of hairs that were 3 cm or shorter and who shed at least 100 hairs were diagnosed as having CTE; 34 with 10% or more of hairs that were 3 cm or shorter and who shed at least 100 hairs were diagnosed as having AGA + CTE; and 14 with fewer than 10% of hairs that were 3 cm or shorter and who shed fewer than 100 hairs were diagnosed as having CTE in remission.
  
  
  CONCLUSIONS
  This method is simple, noninvasive, and suitable for office evaluation.
authors.affiliation: Department of Endocrinological and Metabolic Sciences, Section of Dermatology, University of Genoa, Genoa, Italy. reb-dermo@unige.it
authors.forename: Alfredo
authors.initials: A
authors.lastname: Rebora
authors.forename: Marcella
authors.initials: M
authors.lastname: Guarrera
authors.forename: Manuela
authors.initials: M
authors.lastname: Baldari
authors.forename: Federica
authors.initials: F
authors.lastname: Vecchio
mesh_terms: D000328:Adult; D000505:Alopecia / Q000150:complications / Q000175:diagnosis* / Q000473:pathology; D002908:Chronic Disease; D003627:Data Interpretation, Statistical; D003880:Dermatology / Q000379:methods; D003937:Diagnosis, Differential; D005260:Female; D006197:Hair / Q000473:pathology; D006801:Humans; D008297:Male