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Woolly hair is a rare congenital abnormality of the structure of the scalp hair marked by extreme kinkiness of the hair.
- Familial woolly hair syndrome
- Familial wooly hair syndrome
- Hereditary woolly hair syndrome
- Hereditary wooly hair syndrome
- Wooly hair
- Prevalence: Unknown
- Inheritance: Autosomal dominant or Autosomal recessive
- Age of onset: Infancy, Neonatal
- ICD-10: Q84.1
- OMIM: 194300 278150 604379 615896 616760
- UMLS: C0343073 C0345427
- MeSH: C536745
- GARD: 5597
- MedDRA: 10048017
Prevalence is unknown.
Woolly hair can either be present at birth or appear in the first months of life. The curls, with an average diameter of 0.5 cm, lie closely together and usually make the hair difficult to comb; in addition, the hair may be more fragile than usual. The hair growth rate is usually normal but the anagen phase may be truncated, with the result that the hair does not grow to be long. Woolly hair either shows a generalized distribution affecting the entire scalp or a localized circumscribed distribution in the form of a woolly hair nevus (see this term). A diffuse partial form, manifesting during adolescence and adulthood, have also been described. In many cases, woolly hair is associated with hypotrichosis. Woolly hair can also be syndromic, occurring in combination with dilated cardiomyopathy and palmoplantar keratoderma (Carvajal syndrome), with arrhythmogenic right ventricular cardiomyopathy and palmoplantar keratoderma (Naxos disease), or with growth failure and neurological symptoms (Menkes disease) (see these terms).
Isolated forms are mostly due to homozygous or sometimes compound heterozygous mutations in the genes lipase H (LIPH) and lysophosphatidic acid receptor 6 (LPAR6), that act along a common pathway which plays an important role in the control of hair growth as well as hair texture. In only very few patients, heterozygous mutations have been reported in two keratin genes, namely KRT74 and KRT71. The syndromic forms are due to mutations in desmoplakin (DSP) (Naxos disease), plakoglobin (JUP) (Carvajal syndrome), and ATPase copper transporting alpha polypeptide (ATP7A) (Menkes disease). Just recently, mutations have been identified in KANK2, which encodes the steroid receptor coactivator (SRC)-interacting protein (SIP), for a family with woolly hair and keratoderma without any accompanying heart defects. The etiology of diffuse partial woolly hair and of sporadically occurring woolly hair nevi is unknown.
A thorough dermatological examination with an evaluation of the entire integument should be performed and may also identify any associated manifestations. The examination of the hair shafts by light and electron microscopy reveals an elliptical cross section, variations in caliber, axis rotation and kinked formation, as well as non-homogeneous keratinization. In some cases trichorrexis nodosa is evident. If necessary, the anagen/catagen ratio can be determined using a trichogram. In cases of diffuse partial woolly hair, an increase in intermediate follicles can be detected histopathologically.
Differential diagnosis includes acquired progressive curling of the hair, allotrichia circumscripta symmetrica, acquired partial kinky hair (see this term) and drug-induced kinky hair.
Generalized forms due to KRT74 and KRT71 mutations are autosomal dominant, and forms due to LIPH and LPAR6 mutations are autosomal recessive. Syndromic forms are all recessive. Sporadic forms may also occur. Follicular mosaicism is likely, while an autosomal dominant transmission has also been discussed for diffuse partial woolly hair.
Management and treatment
No treatment is currently available. Depending on their size and location, woolly hair nevi can be excised. Harsh physical and chemical cosmetic treatments should be avoided. If the presence of a syndrome is suspected, an extensive internal investigation, with a detailed cardiological diagnostic examination, is necessary.
Woolly hair is most pronounced during childhood; the manifestations often become less severe in adulthood.
- Review article
- English (2015)