Knowledge is power!... Trichorrhexis nodosa (This is why many people find it difficlt to grow long hair) One of the most common hair shaft defects a dermatologist encounters is trichorrhexis nodosa (also called trichonodosis). Trichorrhexis nodosa is a focal defect in the hair fiber. When observed under the microscope most of a hair shaft looks entirely normal. However, in isolated spots along the length of a fiber swelling and/or fraying can be seen. These focal defects develop where there is an absence of cuticle. The cuticle encases the hair cortex in a strong almost impenetrable layer. It provides physical support and helps protect the cortex of a hair shaft from environmental factors such as ultra violet light, chemicals such as detergents and physical action such as hair brushing. If the cuticle is absent then the cortex underneath is directly exposed. The cortex is less resistant to the physical and chemical factors in the environment compared to the cuticle. Where the cortex is exposed its integrity is broken down. The chemical bonds that maintain the hair structure can break down and the hair becomes more flexible and weaker. The hair may split and fray into minute strands at the point of cuticle break down. This focal disruption of the hair fiber is a prime area for hair shaft breakage. As we comb, brush, and generally manipulate our hair, these defective nodes in the hair fiber may break. Causes of trichorrhexis nodosa can be congenital or acquired. Some people have naturally weak hair where the cuticle is not properly produced. This influence is often hereditary and runs in families. Congenital trichorrhexis nodosa is very rare and it often first develops at a very young age. Abnormal production of hair fiber that is irregular and brittle can occur in metabolic disorders such as those that involve abnormal urea synthesis, abnormal copper or zinc metabolism, or defective cysteine or sulfur incorporation into hair fiber (trichothiodystrophy). Trichorrhexis nodosa is more likely to be acquired through excessive manipulation of hair. Too much brushing, hairstyles that put constant stress on the hair, excessive washing, dying, and perming may disrupt the cuticle in focal areas along a hair shaft. Trichorrhexis nodosa is seen in people who repeatedly use hot combs or permanent waves to style their hair. Once the cuticle is removed then the hair cortex swiftly breaks down. Trichorrhexis nodosa develops in association with a range of other hair diseases. Any hair condition that weakens the hair shaft and/or results in abnormal cuticle formation can result in Trichorrhexis nodosa like hair breakage. Hair loss through breakage can be seen in conditions such as alopecia areata as a secondary phenomenon. Treatment depends on the considered cause of the focal defects. If the hair production is believed to be abnormal then treatment will focus on the hair follicle and improving the strength of hair fiber. Where the defect is the result of excessive grooming the obvious action is to reduce the amount of hair manipulation. People are encouraged to stop using brushes, avoid hair styling that involves chemicals and use only very mild shampoos. Once the integrity of the hair fiber is broken down there is little that can be done to repair it. Often the only answer is to choose a short hair style and cut off the defective hair. It may take some time for hair to recover from trichorrhexis nodosa. New, healthy hair has to grow to replace the defective fibers. It may take several months or even years before scalp hair completely recovers. Split ends Trichoptilosis is a longitudinal splitting of hair fiber better known as "split ends". It develops after the protective cuticle has been stripped away from the end of hair fibers as a result of over processing. Any chemical or physical trauma that weathers the hair may eventually lead to split ends. It can even be induced by vigorous brushing. Typically the damaged hair fiber splits into two or three strands and the split may be two or three centimeters in length. However the greater the damage to the hair fiber the more severe the split ends may be. Splits running several centimeters in length and in multiple strands is possible in severely weathered hair. Occasionally the cuticle stripping and hair splitting develops in the middle of a hair fiber and this results in the hair fiber breaking into more than one strand but held together as a single strand at the scalp root and tip of the hair. Split ends are more likely to develop in brittle hair that may develop due to other hair shaft defect conditions such as bamboo hair (trichorrhexis invaginata), monilethrix, trichothiodystrophy, Netherton's syndrome, and pili torti. Once the cuticle is removed from hair fiber it is impossible to replace. The best treatment is to cut the hair and remove the split and damaged hair.