Seasonal trichorrhexis nodosa. Role of cumulative damage in frayed hair.

Abstract

A young man acquired trichorrhexis nodosa during two successive summers. Clinical evidence and scanning electron microscopy of the hairs indicated that shampooing, brushing and combing, saltwater bathing and ultraviolet exposure, as additive traumas, accounted for the unusual recurrences. The underlying cause is removal of the hair cuticle. Damage present between clinical appearances of the disorder could be visualized in newly grown hair, but only with the aid of the scanning electron microscope. Severe cuticular damage was reproduced by in vitro methods which simulated the physical and chemical factors involved in this case. The relationships between acquired and congenital trichorrhexis nodosa and split ends of hair are discussed.