title: An ultrastuctural study of hair fiber damage and restoration following treatment with permanent hair dye.
abstract: BACKGROUND
  Hair fibers are comprised of non-nucleated keratinocytes and are biologically dead. Clinical damage to the hair shaft occurs with the application of hair dye. Whether this damage can be repaired and the time frame involved is of interest and may help to determine the optimal interval between repeat applications.
  
  
  OBJECTIVE
  Ultrastructural changes of hair shafts after application of permanent hair dye were observed sequentially in a 26-year-old woman. The dye contained p-phenylenediamine, m-aminophenol, resorcin and hydrogen peroxide as an oxidizer. Scanning and transmission electron microscopy was performed immediately before application of the hair dye and again at 30 min, 1 h, 3 h, 6 h, 1 day, 3 days, 1 week, 2 weeks, 4 weeks, 6 weeks and 8 weeks.
  
  
  RESULTS
  The hair showed cuticular swelling with focal degeneration. In some places there was exposure of the hair cortex due to extensive cuticular detachment. There were many holes of various size in the endocuticle, small focal lacunae along the intercellular space and an ill-defined A-layer especially beneath the area of cuticular detachment. The exocuticle appeared normal. The findings were most dramatic in the 6 h and 1 day specimens and tended to improve gradually thereafter. The 8 week specimen showed near complete restoration of the hair cuticle and return to the precoloring state.
  
  
  CONCLUSIONS
  Hair returns to its precoloring state and this requires 8 weeks.
authors: Department of Dermatology, Yonsei University Wonju College of Medicine, Kangwon-Do 220-701, Republic of Korea.
authors: Hyung Jin
authors: HJ
authors: Ahn
authors: Won-Soo
authors: WS
authors: Lee
mesh_terms: D000328:Adult; D005260:Female; D006201:Hair Diseases / Q000139:chemically induced* / Q000473:pathology*; D006202:Hair Dyes / Q000009:adverse effects*; D018859:Hair Follicle / Q000187:drug effects / Q000293:injuries* / Q000648:ultrastructure*; D006801:Humans; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D012075:Remission, Spontaneous; D013997:Time Factors
chemical_list: D006202:Hair Dyes