Feather disease in humans, also known as pili annulati, is a rare hair shaft disorder characterized by alternating light and dark bands along the hair shaft that give the hair a feathered appearance. It is caused by alterations in the hair’s light reflection properties rather than changes in hair pigmentation.
What causes feathering of the hair in humans?
Feathering of the hair is caused by periodic thinning of the hair shaft cuticle, which leads to the formation of air-filled cavities in the hair cortex. These air spaces alter how light is reflected off the hair, creating an alternating pattern of lighter and darker bands. The exact mechanism leading to the cuticle abnormalities is not fully understood but it appears to be linked to defective keratinization of the hair shaft.
Genetic causes
In most cases, feathering of the hair is caused by genetic changes or mutations affecting the structure and formation of the hair shaft. It can be inherited in an autosomal dominant or autosomal recessive pattern. Mutations in the KRT85 and KRT86 keratin genes have been associated with feathering of the hair.
Other possible causes
While genetics is the primary cause, feathering of the hair may also occasionally result from:
- Metabolic disorders affecting hair growth like thyroid disease
- Nutritional deficiencies of vitamins and minerals
- Damage to the hair follicles from chemicals or trauma
What are the symptoms of feathering of the hair?
The main symptom is the appearance of alternating light and dark bands along the hair shaft, giving the hair a feathered or fluffy texture. Other signs and symptoms may include:
- Both scalp and body hair affected
- Hair may feel coarse or fragile
- No itching, pain or hair loss
- Associated hair shaft abnormalities like trichorrhexis nodosa
- No scalp inflammation or scarring
Does feathering of hair affect hair growth?
Feathering of the hair does not directly affect hair growth. The actual growth rate and cycles of the hair follicles are typically normal. However, the abnormal hair shaft structure caused by cuticle defects makes the hair prone to weathering damage and breakage. Over time, this can lead to reduced hair length and density.
What diseases is feathering of hair associated with?
Feathering of the hair is not associated with any internal diseases or disorders. It is usually an isolated finding without involvement of other organ systems. However, it may be seen along with the following genetic conditions affecting hair growth:
- Pili torti – Twisted, brittle hair shafts
- Monilethrix – Beaded hair with keratinization defects
- Trichorrhexis nodosa – Hair shaft fractures and fraying
- Marie Unna hereditary hypotrichosis – Progressive hair loss
How is feathering of the hair diagnosed?
Feathering of the hair is often easily recognized just by visual examination of the hair. However, the following tests may help confirm the diagnosis:
- Microscopic examination – Evaluates hair shaft abnormalities and cuticle changes
- Light microscopy – Assesses refractive properties causing altered light reflection
- Genetic testing – DNA analysis helps detect causative mutations
Can feathering of hair be cured or treated?
Currently there is no cure for feathering of the hair caused by genetic mutations. However, the following measures can help manage or minimize symptoms:
- Avoid chemical treatments and excessive heat styling to reduce cuticle damage
- Use conditioners and hair strengthening products
- Trim split or damaged ends
- Take nutritional supplements like biotin and silica
- Treat underlying conditions like thyroid disorders
- Wear protective hairstyles
- Consider cosmetic solutions like hair pigments and dyes
What is the prognosis for feathering of the hair?
Feathering of the hair itself does not worsen or progress with age. The appearance and extent typically remains stable over time. However, the damaged and fragile hair is prone to breakage, which can cause reduced hair volume, especially with aging. Proper hair care practices can improve hair resilience and minimize breakage.
Conclusion
Feathering of the hair is a harmless but cosmetically distressing condition caused by structural defects in the hair cuticle and cortex. Genetic mutations affecting keratin proteins are the most common cause. While no treatment can reverse the structural abnormalities, minimizing chemical and thermal damage and taking supplements may help strengthen the hair and reduce breakage. Prognosis is generally good with proper hair care.
Key Takeaways
What is feathering of the hair? | A rare genetic hair condition characterized by light and dark banding of the hair shaft. |
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What causes it? | Mutations in keratin genes leading to abnormalities in hair cuticle and cortex. |
Symptoms | Coarse, fragile hair with a feathered appearance but no itching or hair loss. |
Associated conditions | Other genetic hair shaft disorders like pili torti and monilethrix. |
Diagnosis | Visual inspection, light microscopy, hair mount analysis and genetic testing. |
Treatment | No cure, but minimizing damage and taking supplements improves hair strength. |
Prognosis | Stable appearance but higher breakage risk over time. |