MAMMALIAN HAIR
Trichorrhexis Nodosa: A Transverse Fracture of the
Hair Shaft
Text: Susan Devenish-Mutton. Images: Mike
Morgan.
The characteristics of Trichorrhexis Nodosa are well documented. However, I am pleased to find typical examples of this defect, as it is one of the most common to be found in the hair shaft of men and women.
In the first instance there is a localised loss of cuticle cells which can be the trigger of swelling and consequent fracture, as seen in the image above. The swellings are referred to as nodules and are often seen to be grey or white.
In the next two images below, it can be seen that the cortical fibres, now exposed, give the appearance of two paint brushes, with bristles pushed together, which in fact are the individual cortical fibres, fractured and splayed.
The final image below shows a broken hair, the hair having broken
at the node. Once the hair bends, as seen in one of the images
above, it does not revert back to the perpendicular and a broken
hair is often the consequence.
Causes can be of a mechanical (physical pulling, combing or excessive heat) or chemical nature (permanent wave, lightening or straightening hair products).
The outcome of Trichorrhexis Nodosa depends on the severity of the damage, and how the damage has been caused, or whether the hair is so brittle, in the first instance, and could easily break. Hairs with an underlying structural weakness, where there may be a hereditary defect of the hair keratin, can result in fragile shafts. Careful handling is advisable, with the omission of the use of harsh chemicals and treatments will aid this condition.
Editor's note: The author Susan Devenish-Mutton is a registered and practising trichologist and we thank her for writing this article. Also thanks to Mike Morgan who contributed the images.
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