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The histopathologic diagnosis of traction alopecia: An evidence-based model
Michelle A Pitch1, Leonard C Sperling2
1Dermatology and Dermatopathology, Geisinger Medical Center, Danville, Pennsylvania.
Background:
Traction alopecia (TA) is common, but histopathologic criteria for TA have not been objectively defined.
Objective:
Determine whether the pauci-follicular unit (PFU) can be used as a diagnostic criterion for TA. Compared to a normal follicular unit (NFU), the PFU is a noninflamed follicular unit with an intact sebaceous gland but fewer than 2 follicles.
Methods:
A retrospective review of 25 cases of TA and 25 cases of "normal scalp" was performed. Data included all follicles (by size and phase), sebaceous glands, and total follicular units.
Results:
Comparing data (traction vs normal), we found a significantly higher number of PFUs in cases of TA (median 6 vs 0, P < .001), which can be used as a helpful and easily recognizable diagnostic tool in diagnosing cases of TA.
Limitations:
Comparison to other forms of alopecia was not performed.
Conclusions:
The number of PFUs in an alopecia biopsy can be used to establish the diagnosis of TA.
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