Trichorrhexis Invaginata - An Overview

What Is Trichorrhexis Invaginata?

Trichorrhexis invaginata, also known as bamboo hair, is an abnormality of the hair strand that causes the hair strands to look similar to the knots in a bamboo stalk. It is a typical feature of a disease called Netherton syndrome. The normal, healthy strands of hair appear smooth and even under microscopic examination. However, the hair shaft in trichorrhexis invaginata appears to contain minute nodules (lumps) or ridges that are evenly spaced. Bamboo hair most commonly affects hair on top of the scalp, eyebrows, and eyelashes.

What Is Netherton Syndrome?

Netherton syndrome is a rare hereditary autosomal recessive disorder characterized by congenital ichthyosiform erythroderma (a rare skin disorder characterized by white scales on a background of erythematous red skin over the whole body), an atopic diathesis (characterized by skin atopy or allergy), and a characteristic abnormality of the hair shaft known as trichorrhexis invaginata (bamboo hair). The condition can progress to severe complications in the affected individual, especially in the neonatal phase. Chronic skin inflammation results in flaking and exfoliation of the epidermal cells, thereby predisposing these patients to life-threatening toxic infections, septicemia, and dehydration. Skin manifestations considerably vary from person to person suffering from Netherton syndrome. It is a genetic disorder that results in red, erythematous, scaly, flaky skin all over the body, along with allergy problems.

What Are the Causes of Trichorrhexis Invaginata?

Trichorrhexis invaginata is an autosomal hereditary disorder. Genetic mutation in an inherited gene called SPINK5 (serine peptidase inhibitor Kazal type 5) is believed to cause bamboo hair (trichorrhexis invaginata). An abnormal growth process is believed to occur due to a genetic mutation in this gene.

Trichorrhexis invaginata is characterized by a weak spot in the hair shafts' center (cortex). Weak spots are formed at certain points of the hair strand. The nearby segments of the cortex that are comparatively harder press into these weak spots, causing nodules (bumps) or ridges to form. As a result of this, a bumpy appearance is created on the hair strand. This results in the thinning of hair, making them more susceptible to breakage and making it more brittle. The hair, therefore, breaks very easily.

What Is the Epidemiology of Trichorrhexis Invaginata?

The incidence rate of trichorrhexis invaginata (bamboo hair) is usually estimated to be one case in 50,000 population. Females are more commonly affected by trichorrhexis invaginata (bamboo hair) than males, but all races present the disease.

What Are the Symptoms of Trichorrhexis Invaginata?

The symptoms of this disorder include:

• Brittle and thin hair that breaks very easily (bamboo hair).

• A knotty appearance is seen in the hair shafts.

• Loss of eyelashes.

• Loss of eyebrows.

• Typical hair loss pattern or sparse hair on the scalp.

• Dull, dry hair.

• Hair usually loses its shine and luster.

• Spiky hair formation.

• Short hair due to repeated breakage.

• Hair on the eyebrows begins to resemble matchsticks.

• Children who are suffering from Netherton syndrome may have additional symptoms such as red, flaky skin, allergic reactions, or eczema. Bamboo hair may not develop in these children before the age of two years.

How to Diagnose Trichorrhexis Invaginata?

• Trichoscopy - To diagnose trichorrhexis invaginata, the healthcare professional will pluck a hair from the scalp to examine it under a microscope. It is characterized by an abnormal hair shaft that usually wraps around a distal hair shaft that is firmer than the weak hair shaft, thereby forming a shallow invagination of the distal hair shaft into the weaker hair shaft giving an appearance of a ball and socket configuration under microscopic examination.

• DNA (Deoxyribonucleic Acid) Tests - To diagnose Netherton syndrome, the healthcare clinician may suggest a series of DNA (deoxyribonucleic acid) tests or a skin biopsy to check the genetic mutations. For a skin biopsy, the healthcare professional will remove a small sample of skin tissue to send it for laboratory testing in the lab. These DNA tests are usually performed to diagnose the SPINK5 (serine peptidase inhibitor Kazal type 5) gene for genetic abnormalities.

What Is the Treatment of Trichorrhexis Invaginata?

Since the disorder is a direct result of a genetic mutation, there is currently no known way to prevent the occurrence of the condition. But there are a plethora of lotions (creams) and ointments that can be used to treat the disease condition. These include:

• Emollients (creams that can soften or soothe the skin) and keratolytic agents (especially those with urea, lactic acid, and salicylic acid) moisturize and keep the skin hydrated.

• Oral antibiotics prevent infections in the skin and anywhere on the body.

• Antiallergic drugs are used to reduce itching in the skin.

• Topical corticosteroids are not advised for young children.

• Photochemotherapy (a combination treatment that consists of taking the drug Psoralen and then exposing the skin to long-wave ultraviolet light rays) and oral retinoids (a group of medicines associated with vitamin A).

• The hair breakage can be minimized by making sure that the hair remains hydrated.

• Regularly drink water and avoid the use of heat treatment on hair.

• Alcohol-based hair products should be avoided as they can cause the hair to dry out, which usually worsens the breakage.

• Other hair care products that are aimed at hydrating dry hair can also be used.

• The use of chemicals should be avoided in the hair, such as hair perms. They should not be used on damaged hair, either. If these products are used persistently, they may result in complete permanent hair loss and cicatricial alopecia or scarring alopecia (an inflammatory condition where the hair follicles are destroyed). This pattern of hair loss can scar the hair follicles, ensuring that future hair growth is less likely.

What Is the Outlook for People With Trichorrhexis Invaginata?

Although the disorder cannot be prevented or cured completely because it occurs due to a genetic mutation, there are several ways to manage the hair symptoms by maintaining the hydration of the dry, frizzy hair and allowing proper skin healing.

The harmful chemicals that dry the hair and scalp should be avoided completely. The hair care products that hydrate the hair are advised by healthcare professionals. Emollients and lotions that can alleviate the symptoms should be used. The disease also improves with age, even when it is left untreated.

Conclusion

Trichorrhexis invaginata is a distinctive hair strand defect characterized by thin, dry, and brittle hair. It is also known as bamboo hair. It can even affect the hair of the scalp, eyelashes, and eyebrows. It is impossible to prevent the disease since it is a genetic disorder. But taking good care of the brittle hair along with maintaining hydration can improve the hair quality.