Which tests are performed in the workup of telogen effluvium?

Updated: Jun 13, 2018
  • Author: Elizabeth CW Hughes, MD; Chief Editor: Dirk M Elston, MD  more...
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Answer

Laboratory studies are of little use in the diagnosis of telogen effluvium if there is clear history of an inciting event. Scalp biopsy is the most useful test to confirm the diagnosis, although this is seldom necessary if the history is characteristic and a gentle hair pull produces numerous telogen hairs. Telogen hairs are identified by a white bulb and the lack of a gelatinous hair sheath.

If a biopsy is performed, some authors advocate taking three 4-mm punch biopsy specimens, all imbedded horizontally. This method provides a generous sample for determining anagen-to-telogen and terminal-to-vellus ratios and leads to greater diagnostic accuracy. [24]

Chronic telogen effluvium may have a metabolic cause. Testing should be directed toward causes that are common and correctable. If any sign or symptom of hypothyroidism is present, a thyrotropin test is warranted. Iron deficiency is common in premenopausal women. Evaluation of CBC count, serum iron, iron saturation, and ferritin may be warranted. Note that CBC count results may be completely normal in women with mild iron deficiency and hair loss, particularly in women older than 40 years. Blood is more essential than hair, and the body will shed hair before red cell indices become microcytic. Also, note that ferritin behaves as an acute phase reactant. Inflammation can produce normal ferritin levels in an individual who is iron deficient. Although a low ferritin is proof of iron deficiency, a normal ferritin level does not exclude iron deficiency. Some experts in the field regard iron saturation as the most sensitive indicator of iron deficiency.

Occasionally, screening for renal and hepatic enzymes may detect a systemic cause of hair shedding. If syphilis is considered as a cause of hair loss, a rapid plasma reagin or Venereal Disease Research Laboratory test should be preformed.


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