Trichoscopy

Trichoscopy is the magnified examination of the scalp and hair shafts, usually with a dermatoscope at 10x to 70x magnification. It is the standard tool for distinguishing the major categories of hair loss in dermatology practice and has largely reduced the need for scalp biopsy in straightforward cases.

Characteristic findings by condition:

• Androgenetic alopecia: variability in hair shaft diameter within a small scalp area (the diagnostic signature of miniaturisation), peripilar brown halos, single-hair follicular units replacing the normal multi-hair units.
• Alopecia areata: “exclamation mark” hairs (short, broken, tapered toward the scalp) at active patch borders, yellow dots (empty follicular ostia), broken hairs.
• Scarring alopecias: loss of follicular openings (a smooth featureless scalp where pores should be), perifollicular erythema and scaling in active disease (lichen planopilaris, frontal fibrosing alopecia).
• Trichotillomania: broken hairs of varying lengths, “flame hairs”, irregular patch borders without typical AA features.

Trichoscopy in a primary-care setting is uncommon; in dermatology it is standard. If hair loss diagnosis is uncertain, a dermatologist with trichoscopy will sort it out faster than further self-investigation.