Weathering of hair in trichothiodystrophy.

The structure of hairs from three patients with sulphur-deficient hair, trichothiodystrophy, has been studied by light, plane-polarizing and scanning electron microscopy. Severe cuticular and secondary cortical degeneration was evident along almost the entire length of the hair shaft, with cuticle loss, trichorrhexis nodosa formation and trichoschisis. The severity of these changes varied between patients. The role of the cuticle in protecting hair from environmental damage is discussed.