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- Presentation
Trichoscopic Diagnosis and Biopsy Techniques for Alopecia
Description
The talk reviewed how to use trichoscopy and scalp biopsy to diagnose alopecia, emphasizing that a normal scalp shows follicular units with multiple terminal hairs plus vellus hairs and that the whole scalp should be examined by comparing frontal, mid-scalp, vertex, and occipital areas. The speaker organized alopecia into diffuse, patchy, and marginal patterns and stressed that biopsy should be taken from active disease margins, not scarred or fully bald areas, and angled along the direction of hair growth to avoid transecting follicles. Several biopsy sectioning methods were described, including horizontal, vertical, and combined techniques, with horizontal sections favored for follicle counts, cycling, and miniaturization, and vertical sections useful for epidermal/dermal changes and inflammatory patterns. Trichoscopic findings were then linked to major hair-loss disorders: androgenetic alopecia shows anisotrichosis, miniaturization, fewer hairs per follicular unit, and a brown peripilar halo with mild chronic inflammation; telogen effluvium shows diffuse shedding with decreased density and empty follicles but lacks a specific trichoscopic sign; alopecia areata shows yellow dots, exclamation point hairs, broken/tulip hairs, black dots, and a peribulbar lymphocytic infiltrate on biopsy; CCCA shows a white-gray peripilar halo and perifollicular fibrosis; lichen planopilaris and frontal fibrosing alopecia show perifollicular scale, erythema, and lichenoid inflammation; and traction alopecia is suggested by hair casts, perimeter scale, directional pulling, and loss of vellus hairs. The speaker highlighted overlap cases, the value of trichoscopic-assisted biopsy, and the importance of early diagnosis because some patients can still recover meaningful hair with appropriate treatment.
View moreConclusions
- Scalp trichoscopy and properly targeted biopsy are essential for distinguishing the major causes of hair loss and avoiding missed or misclassified diagnoses.
- Biopsies are most informative when taken from active disease at the advancing edge or within affected but still-haired areas, rather than from fully scarred or completely bald skin.
- Horizontal and vertical sectioning provide complementary information, with horizontal sections being especially valuable for follicle count, cycling, and miniaturization.
- Androgenetic alopecia is characterized by follicular miniaturization, hair-shaft diameter variability, and often a brown peripilar sign that reflects early perifollicular inflammation.
- Telogen effluvium is usually a diffuse, nonspecific shedding disorder with no unique trichoscopic signature and is often a diagnosis of exclusion.
- Alopecia areata can be recognized by yellow dots, exclamation-point hairs, black dots, and other broken-hair patterns, and diffuse forms can be missed without trichoscopic examination.
- Long-standing alopecia areata becomes harder or impossible to reverse once follicles are lost, so earlier recognition and treatment matter.
- CCCA, lichen planopilaris, and frontal fibrosing alopecia show scarring-pattern signs such as white-gray or tubular perifollicular halos, perifollicular scale, and fibrosis.
- FFA and LPP can occur in men as well as women and may be mistaken for traction alopecia unless trichoscopy is used carefully.
- Traction alopecia is suggested by hair casts, perishaft scale, directional pulling, and loss along tension-bearing hairline areas, and early intervention can still allow meaningful regrowth.
- Hair loss disorders may overlap, so combining clinical exam, trichoscopy, and histology improves diagnostic accuracy and guides more appropriate treatment.
- Different alopecias require different therapies, and some patients can regain substantial hair when the underlying condition is identified and treated promptly.
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