Principles of Trichoscopy

Trichoscopy, also known as dermoscopy of the hair and scalp, is a non-invasive diagnostic method using polarized or non-polarized light magnification. It visualizes hair shafts, follicular openings, and vascular patterns.

Clinical Utility

Differential diagnosis: Distinguishing between scarring and non-scarring alopecias.
Activity assessment: Identifying signs of inflammation that may affect treatment planning.
Treatment monitoring: Documenting changes in hair density and shaft diameter.
Biopsy guidance: Selecting optimal sites for tissue sampling.

This non-invasive visualization is a standard component of hair loss evaluation.

Scarring vs. Non-Scarring Alopecia

This distinction helps determine treatment pathways.

Non-Scarring Alopecia

Follicular openings are visible and intact.
Hairs thin but follicles remain.
Examples: Androgenetic alopecia, alopecia areata, telogen effluvium.

Scarring Alopecia

Fibrosed or destroyed follicular openings.
Permanent absence of follicular pores.
Examples: Lichen planopilaris, frontal fibrosing alopecia.

Trichoscopic Patterns by Condition

Androgenetic Alopecia

Hair diameter diversity greater than 20%
Peripilar signs
Yellow dots
Vellus hairs

Alopecia Areata

Yellow dots
Exclamation mark hairs
Black dots (broken hairs)
Cadaverized hairs

Scarring Alopecias (LPP, FFA)

White dots (fibrosed follicular openings)
Perifollicular scaling
Erythema
Loss of follicular openings

Trichotillomania

Broken hairs of varying lengths
Flame hairs
Coiled or tulip hairs
V-sign (split ends)

Key Clinical Points

Trichoscopy is a first-line, non-invasive diagnostic tool for hair loss evaluation.
Androgenetic alopecia shows hair diameter diversity greater than 20% and increased vellus hairs.
Alopecia areata presents with yellow dots and exclamation mark hairs.
Scarring alopecias show white dots, loss of follicular openings, and perifollicular scaling.

Trichoscopy & Digital Analysis