International Journal of Trichology

: 2022  |  Volume : 14  |  Issue : 5  |  Page : 188--189

Pili trianguli et canaliculi: A case report with 10-year follow-up

Suparuj Lueangarun1, Therdpong Tempark2, Ratchathorn Panchaprateep3,  
1 Division of Dermatology, Chulabhorn International College of Medicine, Thammasat University, Amphur Klongluang, Pathumthani, Thailand
2 Department of Pediatrics, Faculty of Medicine, UniversiChulalongkornty, Pathumwan, Thailand
3 Department of Medicine, Division of Dermatology, Faculty of Medicine, Chulalongkorn University, Pathumwan, Bangkok, Thailand

Correspondence Address:
Suparuj Lueangarun
Division of Dermatology, Chulabhorn International College of Medicine, Thammasat University, Amphur Klongluang, Pathumthani 12120, Bangkok

How to cite this article:
Lueangarun S, Tempark T, Panchaprateep R. Pili trianguli et canaliculi: A case report with 10-year follow-up.Int J Trichol 2022;14:188-189

How to cite this URL:
Lueangarun S, Tempark T, Panchaprateep R. Pili trianguli et canaliculi: A case report with 10-year follow-up. Int J Trichol [serial online] 2022 [cited 2023 Feb 7 ];14:188-189
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Pili trianguli et canaliculi is also known as uncombable hair syndrome or “spun glass hair syndrome,” a relatively rare nonfragile, congenital hair shaft disorder, with unruly hair of no fragility, difficulty to style, and childhood-onset appearance of standing away from the scalp. Diagnosis can be confirmed by scanning electron microscopy (SEM), showing characteristic canal-like longitudinal groove along the shaft and more than 50% of scalp hair with triangular or kidney-shaped cross-section. The hypothesized mechanism in pili trianguli et canaliculi is the abnormality of dermal papilla shape, resulting in premature keratinization of a triangular-shaped inner root sheath and asymmetric matrix defect of longitudinal grooves along the hair shaft.[1] While, the physicochemical properties of stress-strain, amino acid, and X-ray diffraction of pili trianguli et canaliculi are within normal ranges. Furthermore, a reduced amount of extractable fibrous protein can be observed in some patients.[2] Despite most sporadic occurrences of this condition, there are autosomal dominant and autosomal recessive variants, with the implication of genes in the autosomal recessive variants, including transglutaminase 3, trichohyalin, and peptidylarginine deiminase 3.[3],[4] However, there is no definitive therapy for pili trianguli et canaliculi.[5]

A 30-year-old male presented with a 20-year history of frizzy, unruly and difficult to style hair, even to brush or comb, and unmanageable growth of hair length without abrupt breakage. Medical history revealed his normal straight hair at the age of 3 years, without the same hair condition in other members of his family. On hair and scalp examination, black color was seen in diffuse dry frizzy appearance on the entire scalp, projecting away, and resisting any attempts to be flattened [Figure 1]. Hair pulling and hair tug tests were negative. Other physical examinations were within the normal limits. The light microscopy (×10 original magnification) showed longitudinal groove along hair shaft [Figure 2]. The dermoscopy (×10 original magnification) displayed longitudinal groove and multiple-directional growth. The SEM (×500–750 original magnification) yielded the entirely rigid hair shaft with longitudinal groove and triangular shape on cross-section [Figure 3].{Figure 1}{Figure 2}{Figure 3}

A diagnosis of pili trianguli et canaliculi was made, with biotin 5 mg oral daily and chelated zinc 15 mg oral twice daily prescribed for 6 months. Unfortunately, only softening hair was revealed for 3 months and the hair was still uncombable. Nonetheless, this hairstyle is now accepted by the patient according to the fashionable trend at that time. He was followed for 10 years, still with his frizzy hair. Hence, he decided to have short hairstyle due to no treatment for his hair condition.

Our case is highlighted by pili trianguli et canaliculi, with the characteristic findings of clinical presentation, light microscopy, and SEM. Moreover, molecular genetic testing was suggested to ratify and confirm the causative gene mutations, with further investigation of an efficacious treatment modality for this hair condition.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

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Conflicts of interest

There are no conflicts of interest.


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