Dermatology Education

Trichorrhexis Nodosa (Hair Breakage)

Kesha J. Buster, MD and Anna Levin, BA

Background
Trichorrhexis nodosa (TN) is a common disorder characterized by hair breakage due to weak points in the hair. Though there are inherited forms, the most common type of TN is due to physical or chemical trauma to the hair.  It occurs more frequently in individuals of African origin with curly hair.1 The spiral shape of the hair follicle and hair shaft predispose African hair to breakage.2 African hair naturally is less dense and grows slower than hair of other ethnic groups3 and it is at increased risk for significant damage when exposed to cosmetic treatments.

Cause
Even in its natural state, African hair is more vulnerable to breakage. The curlier the hair, the more it is susceptible.2 It also has a tendency to form knots naturally, and when the knotted hair is combed, hair breakage can occur.1,4 However, there are 4 major hair care practices that lead to hair breakage5,6: heat, chemical straightening or permanent waving, permanent hair color, and drying hair products.

Heat: Heated hair styling tools (e.g., blow dryer, hot combs, curling irons, flat irons) use extremely high temperatures to temporarily alter hair shape and style. This heat can weaken hair and cause it to break.7-8 In addition, the hot oil sometimes used during this process may also run down to the scalp and may contribute to scarring leading to permanent hair loss.8-9

Chemical: All chemical relaxers and permanent waves damage the hair shaft, making hair more fragile.10-12 They remove the outer protective layer of the hair shaft, break chemical bonds,  alter hair amino acid composition, leading to weaker hair that is more brittle  dry, and  less shiny.8,11,13

Color: Permanent hair color changes the chemical composition of the hair leading to weaker hair.12,14 Repeated use can lead to hair breakage, split ends, undesirable hair feel, and dull appearing hair.14,15 Semi- or demi-permanent color and temporary colorants have less negative effects.12

Drying: Because of its curly nature, African hair is not readily coated with natural scalp oil.16 Washing hair too frequently prevents the natural scalp oil from coating and protecting hair leaving it overly dry. In addition, hair gels, sprays, and other styling agents mold the hair and can cause breakage especially when hair is combed, brushed or otherwise manipulated with the product(s) in the hair.5,17 The use of drying shampoos without moisturizing conditioners can exacerbate dryness and breakage.

Other:  Frequent physical damage from combing, brushing, scratching, or excessive scalp massage, can also cause hair breakage.5,17  In addition, pulling of hair via tight braids, twists, extensions, weaves, or other tight styles may increase knotting and the likelihood of breakage.1  Another possible cause of hair breakage is fungal infection of the scalp and/or hairs. This is more common in African-American children, but is not rare in African-American women.18 Diseases also associated with the condition include hypothyroidism, Menkes’ kinky hair syndrome, Netherton syndrome, and ectodermal dysplasia.

Any combination of the above causes of hair breakage will have a cumulative effect.

How do I know if I have trichorrhexis nodosa?
Hairs tend to break mid-shaft after minimal manipulation. There may be areas of your scalp with shorter hair. You may notice small white nodes on your hair that correspond to splits in the hair.17 You also might observe breakage at the junction of processed and new hair growth close to the scalp, especially at the back of the head and nape of the neck.8 You may feel as if your hair is not growing, and your scalp may be itchy, red or sore.19

Treatment
Once hairs are broken, they cannot be mended so prevention is the key. Limit physical stress to the hair (e.g., combing, scratching). If your scalp itches, anti-dandruff shampoos may be helpful, but these may also dry out African hair.

Consider wearing hair in its natural state as avoidance of heat and chemicals is optimal to allow your hair to recover. However, if relaxers are desired, apply a protective ointment such as petrolatum to the scalp prior to application (i.e., base), and only apply the chemicals to new hair growth to avoid further damage to previously relaxed hair.5,10 Consider ammonium bi-sulfate cream relaxers, which are the least damaging; but keep in mind that these are not permanent.11 If a permanent relaxer is desired, have it professionally applied no more frequently than every eight weeks.19 Relaxers should be followed by thorough rinsing with neutralizing shampoo.13 Wait at least 2 weeks after relaxing/waving to permanently color hair.12 An alternative is to use temporary colorants or semi-permanent hair dyes, which are less damaging and can be used the same day as chemical straighteners.12

Limit use of heat on the hair as much as possible, using heat once weekly at the most. Use hot comb/curling iron/flat iron only on clean dry hair.5

Use conditioning shampoos and moisturizing conditioners with ingredients that will protect the hair.12-13 Such moisture-binding ingredients include sodium PCA, glycerine, panthenol, chitosan, dimethicone and/or silicone.13,20 Use of leave-in conditioners6 or weakly heated deep conditioning treatments containing such ingredients may also be helpful, as prolonged application13 helps to coat and protect the hair.

If braiding, extensions, or weaving are used, a “tight pull” should be avoided. No hair style should ever be painful. Braided styles should be removed every 6-8 weeks8 to avoid accumulation of debris and locking which, when removed, can contribute to breakage.

Avoid use of hair products containing alcohol.12-13 Limit grooming of hair when it is styled with hair products. Wash or rinse products from hair prior to restyling.5 Regularly trim the damages ends.

A visit to a dermatologist may be necessary to tailor the treatment regimen and possibly rule out an underlying fungal infection in cases that are refractory to the above measures.

Additional Resource
North American Hair Restoration Society

References

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3. Loussouarn G. African hair growth parameters. Br J Dermatol 2001;145:294-97.
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