Trichorrhexis Nodosa Workup

Updated: May 26, 2022
  • 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. [35] 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.