Hair shaft abnormalities are either congenital or acquired defects in the hair strand that present in a variety of ways. These can range from a simple change in colour of the hair to alterations to its density, length, structure, and growth. Hair shaft abnormalities are often a result of structural changes within the hair fibres, that later lead to brittle and uncombable hair. Patients suffering from such dysplasia often have dry lustre-less hair that is significantly fragile, and these disorders can drastically affect a person’s self-esteem. The unhealthy appearance the hair assumes is one of the most common complaints for which individuals seek professional help. Hair shaft abnormalities can occur secondary to both endo and exogenous aetiologies. These include a genetic predisposition in some individuals resulting in deformed hair since birth or acquired hair shaft abnormalities due to vigorous or improper hair care practice.

These disorders can be further divided into two subsets:

• conditions that increase hair fragility and;
• another set of conditions that do not impart such effects.

Below are a few common forms of hair shaft abnormalities that are frequently encountered by the general population.

Trichorrhexis Nodosa

Trichorrhexis nodosa falls in the category of hair shaft disorders that increase hair fragility. It is characterized by the formation of nodules along the hair shaft that causes the hair to break off easily. The result is a lack of apparent hair growth with damaged-looking hair that frequently has whitish discoloration and split ends on its tips. Trichorrhexis nodosa may be congenital in origin but is usually precipitated by trivial injuries such as chemical or heat burns and aggressive hair brushing, etc. It is regarded as the most common congenital defect of the hair shaft.

Management

In the majority of cases, Trichorrhexis nodosa can be prevented by avoiding hair damaging habits such as aggressive hair brushing and styling, strong chemicals, and heating devices. Fortunately, the condition is self-limiting and improves when healthy hair care routines are restored. These include gentle brushing, using hair conditioners and strengthening serums, and avoiding harsh shampoos, chemicals, and heat ironing during the acute episode.

Monilethrix

Monilethrix is a hair shaft disorder that has a characteristic beaded hair strand appearance like a string of beads in a necklace. This is due to the presence of periodic nodes and constrictions along the length of the hair fiber that significantly weakens the hair strands. The resulting brittle hair rarely grows to its maximum potential due to premature breakage, resulting in short sparse hair that breaks easily. The condition most commonly affects the back of the scalp and neck, sparing the front hairline. However, in severe cases, it may involve the whole scalp along with hairy parts of the body such as eyelashes, eyebrows, pubic and axillary hair. Monilethrix frequently presents in childhood and being a hereditary disorder, is known to run in families. Management The condition may spontaneously resolve in many individuals, however, its persistence in adulthood is also frequently reported.

Monilethrix is known to improve at puberty, pregnancy, and with the use of oral contraceptives. Multiple studies show the efficacy of retinoid therapy to impart satisfactory results in individuals suffering from monilethrix. However, relapses are also commonly documented with discontinuation of the drug. Topical and low-dose oral minoxidil have also been employed to manage the condition in certain patient populations. Other than medications, a gentle hair care routine and avoidance of harsh chemicals and heating are also recommended to hasten the recovery period.

Bamboo hair

Trichorrhexis invaginata, also known as Bamboo hair, is a disorder in which the hair shaft invaginates itself at several points along its length giving a similar appearance as a bamboo stalk. Under a microscope, several episodic invagination nodules are visible unlike the smooth surface of a normal hair strand. Trichorrhexis invaginate commonly occurs as a feature of a syndrome called the Netherton syndrome, where several other dermatological complaints are also found. The condition is commonly known to affect hair on top of the scalp, eyebrows, and eyelashes. The affected individuals have hair that is in a knotty bamboo strand-like in appearance and breaks easily. The hair is also dry, lusterless, and short due to frequent breakage.

Management

There is no single modality at present to prevent the occurrence of bamboo hair or provide a complete cure. However, it can be managed to some extent with the use of hydrating and moisturizing products such as conditioners and hair serums. Avoiding products and hairstyling practices that are tough on hair strands are also advised in such patients.

Bubble hair

Bubble hair is an acquired condition, that true to its name has a characteristic bubble-like deformity visible under microscopy. The condition is a consequence of excessive heat treatment to hair strands such as using high heat hairdryers, straighteners, and heating tongs and curls. With the heat, the moisture in the innermost layer of the hair fiber evaporates leaving a bubble-like cavity that is visible under a microscope. This results in hair shafts that are dry, lusterless, and excessively fragile. Bubble hair may also be found in association with other acquired hair shaft disorders such as trichorrhexis nodosa and trichoptilosis.

Management

The best way to prevent bubble hair is to minimize the usage of hair traumatizing devices in daily life. Even when opting for a heat-based styling device one must ensure keeping the temperature to low or medium. Incorporating moisturizing shampoos, conditioners, and hair creams are also believed to be effective for individuals with bubble hair.

Conclusion

The majority of hair shaft abnormalities are acquired and are secondary to excessive cosmetic treatments. Therefore, these conditions are majorly preventable with adequate hair care and change in hairstyling practices. In general, short hair seems to be suitable for patients with hair shaft disorders. Most of the cases positively respond to avoidance of strong external stimulus and nourishing hair care routines. However, it is also essential to seek medical advice when encountering such complaints to exclude any underlying medical conditions. 

Referenced from Trichology.com