Weathering of Hair in Hereditary Hair Abnormalities

Abstract

Scanning electron microscopic studies have considerably enhanced our knowledge of newly-formed hair, and have shown that from root to tip the shaft degenerates progressively (‘weathering’) due to such factors as brushing, combing, ultra-violet radiation and a variety of cosmetic procedures (Dawber and Comaish 1970, Swift and Brown 1972, Robinson 1976, Garcia et al. 1978). It has also been clearly demonstrated that Trichorrhexis nodosa is simply the severest form of weathering usually due to excessive cosmetic treatment (Chernosky 1974). Severe weathering may occur in hereditary dystrophies in which no cosmetic treatment has been carried out or in association with procedures that are generally harmless to hair, e.g. shampooing. Previous preliminary qualitative studies have shown that breakdown of hair in many hereditary abnormalities is in many respects specific to that dystrophy and different from ‘normal’ weathering (Dawber 1977, Dawber 1978).