Trichorrhexis Nodosa Workup

Updated: May 28, 2019
  • Author: Robert A Schwartz, MD, MPH; Chief Editor: William D James, MD  more...
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Workup

Laboratory Studies

Light and electron microscopy of the affected areas reveal a decreased or absent cuticular cell layer and the characteristic paintbrush bristle appearance of trichorrhexis nodosa. More precisely, it resembles a crushed paint brush and is called a "paint brush fracture." [3] In patients with underlying trichothiodystrophy, polarized light shows the typical appearance of alternating light and dark bands on the shaft, the so-called tiger-tail pattern. [28] Fungal microscopy and culture may be performed if necessary. Patients suspected of having an underlying congenital disorder because of a young age at onset and because of the presence of associated symptoms warrant further investigation.

Analysis of the hair shaft may reveal a chemical deficiency caused by a metabolic disorder (eg, low sulfur level in trichothiodystrophy). Serum and urine amino acid levels should be investigated.

Other blood tests may include copper level tests, iron studies, blood cell counts, and liver and thyroid function tests.

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Imaging Studies

A CT of the brain and an EEG may aid in diagnosis if mental retardation is present.

Tortuous intracranial vessels and bladder diverticula may be present at early stages and may suggest this diagnosis. [29]

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Other Tests

Dermoscopy shows breakage in hair shafts at multiple levels, producing an appearance suggestive of the ends of two brushes aligned in opposition, resembling “thrust paint brushes.” [23, 24, 30] High-power magnification demonstrates these fibers in detail, while at low power, these structures appear as light-colored nodules or gaps located along the hair shaft. [24]

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