What is the role of lab studies in the workup of androgenetic alopecia?

Updated: Mar 05, 2020
  • Author: Robert P Feinstein, MD; Chief Editor: Romesh Khardori, MD, PhD, FACP  more...
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The most important aspects are the history and the physical examination. In the case of a woman, if virilization is evident, laboratory analysis of dehydroepiandrosterone (DHEA)-sulfate and testosterone may need to be obtained. Some authors have suggested that total testosterone level alone may be adequate to screen for a virilizing tumor. If a thyroid disorder is suspected, obtaining a thyrotropin level is indicated.

If telogen effluvium is present, laboratory analysis of serum iron levels or a biopsy to note an underlying papulosquamous disorder may be indicated. Telogen effluvium may accelerate the course of pattern alopecia. Iron deficiency is a common and reversible cause of telogen effluvium. A normal CBC count does not exclude iron deficiency as a cause of hair loss. While a low ferritin level is always a sign of iron deficiency, ferritin behaves as an acute phase reactant, and levels may be normal despite iron deficiency. Iron, total iron-binding capacity, and transferrin saturation are inexpensive and sensitive tests for iron deficiency.

Diffuse alopecia areata may mimic pattern alopecia. The presence of exclamation point hairs, pitted nails, or a history of periodic regrowth or tapered fractures noted on hair counts suggests the diagnosis of diffuse alopecia areata.

Schmidt et al used dermoscopy to study androgenetic alopecia. They noted brown peripilar casts and miniaturized hairs. [26]

Köse and Güleç examined the value of dermoscopy in the study of alopecias, finding that hair diameter diversity was seen in every patient with androgenetic alopecia. This was an essential but not specific finding of this alopecia because it was also present in alopecia areata, chronic telogen effluvium, and primary cicatricial alopecia. However, peripilar signs and empty follicles were indicative of androgenetic alopecia, as they were confined to this patient group. [27]

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