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December 6, 2010

Picture of the Month—Diagnosis

Arch Pediatr Adolesc Med. 2010;164(12):1166. doi:10.1001/archpediatrics.2010.228-b

Denouement and Discussion: Uncombable Hair (Pili Trianguli et Canaliculi)

The clinical features and dermoscopy and electron microscopy findings lead to the diagnosis of pili trianguli et canaliculi, or uncombable hair syndrome. The (unworried) patient and his family were reassured that the condition is harmless and would improve over time, as had been observed with the patient's sister. Uncombable hair syndrome was first described in 1973 by Stroud and Mehregan1and by Dupré and colleagues.2This syndrome is a rare, genetically determined hair shaft abnormality transmitted in an autosomal dominant fashion with variable penetrance. As an underlying pathologic condition, a keratinization disorder of the hair shaft is suspected. The clinical presentation is highly distinct, with silvery-blond, dry, frizzy hair that stands out from the scalp and is resistant to combing.3The phenotype is the result of the longitudinal grooving of the hair shaft.4The anomaly is limited to the scalp hair.5Occasionally, pili trianguli et canaliculican be found in children with normal-appearing hair. In contrast to uncombable hair syndrome, the hair shaft abnormality is only present in a limited number of hairs, and with absence of the characteristic phenotype, this can be considered a variation from the norm. In individuals with uncombable hair syndrome as manifested in our patient, however, the vast majority of the scalp hair (>50%) demonstrates grooving and triangular shape, so by observing this feature, together with the clinical appearance of unruly, frizzy hair, the diagnosis can be made.6

This hair phenotype usually occurs as an isolated condition and without any associated symptoms. Nevertheless, uncombable hair has been reported together with ectodermal dysplasia, hypotrichosis of Marie Unna, retinal dysplasia, pigmentary dystrophy, juvenile cataract, digit abnormalities, tooth enamel anomalies, oligodontia, and angel-shaped phalangoepiphyseal dysplasia.7,8However, in cases of ectodermal dysplasia, a grooving and twisting of the hair shaft (pili torti et canaliculi) can be observed.9Although Shelley and Shelley10report a positive effect of biotin on the hair shaft structure, no specific therapy is recommended in patients with pili trianguli et canaliculibecause the condition usually improves spontaneously with age. Using conditioner can increase hair strength to a certain extent and may improve its appearance owing to the moisturizing effect. Most important, affected individuals and their family members should be informed about the benign and self-limiting nature of this condition and its autosomal-dominant inheritance pattern.

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Correspondence:Lisa Weibel, MD, Department of Dermatology, University Hospital of Zurich, Gloriastr 31, CH-8091 Zurich, Switzerland (lisa.weibel@usz.ch).

Accepted for Publication:March 31, 2010.

Author Contributions:Drs Navarini, Trüeb, and Weibel had full access to all the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis. Study concept and design: Navarini and Weibel. Acquisition of data: Navarini, Kaufmann, Kaech, and Weibel. Analysis and interpretation of data: Navarini, Kaufmann, Trüeb, and Weibel. Drafting of the manuscript: Navarini, Kaufmann, and Weibel. Critical revision of the manuscript for important intellectual content: Navarini, Kaufmann, Kaech, Trüeb, and Weibel. Administrative, technical, and material support: Kaech. Study supervision: Navarini, Trüeb, and Weibel.

Financial Disclosure:None reported.

Stroud  JDMehregan  AH The First Human Hair Symposium.  New York, NY Medcom Press1973;
Dupré  ARochiccioli  PBonafé  JL «Cheveux incoiffables»: anomalie congénitale des cheveux.  Bull Soc Fr Dermatol Syphiligr 1973;80111- 112Google Scholar
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