A guide to assessing damage response pathways of the hair follicle: Lessons from cyclophosphamide-induced alopecia in mice

Sven Hendrix, Bori Handjiski, Eva M.J. Peters, Ralf Paus

Research output: Contribution to journalReview article

76 Scopus citations


After chemical, biological, or physical damage, growing (i.e. anagen) hair follicles develop abnormalities that are collectively called hair follicle dystrophy. Comparatively lower follicular damage induces the "dystrophic anagen" response pathway (= prolonged, dystrophic anagen, followed by severely retarded follicular recovery). More severe follicular damage induces the dystrophic catagen pathway (= immediate anagen termination, followed by a dystrophic, abnormally shortened telogen and maximally fast follicular recovery). In order to recognize these distinct damage response strategies of the hair follicle in a clinical or histopathological context, we have used the well-established C57BL/6J mouse model of cyclophosphamide-induced alopecia to define pragmatic classification criteria for hair follicle dystrophy (e.g., structure and pigmentation of the hair shaft, location, and volume of ectopic melanin granules, distension of follicular canal, number of TdT-mediated dUTP nick end labeling positive keratinocytes in the hair bulb; neural cell-adhesion molecule immunoreactivity and alkaline phosphatase activity as markers for the level of damage to the follicular papilla). These classification criteria for hair follicle dystrophy are useful not only in chemotherapy-induced alopecia models, but also in the screening of drug-treated or mutant mice in a highly standardized, accurate, sensitive, reproducible, easily applicable, and quantifiable manner.

Original languageEnglish (US)
Pages (from-to)42-51
Number of pages10
JournalJournal of Investigative Dermatology
Issue number1
StatePublished - Jan 1 2005
Externally publishedYes



  • Anagen
  • C57BL/6
  • Catagen
  • Chemotherapy
  • Hair follicle dystrophy
  • Hair loss

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Dermatology
  • Cell Biology

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