Trichoscopy in Hair Loss: Differentiating Androgenic Alopecia, Scarring Alopecias, and Trichotillomania

The speaker explains how trichoscopy helps evaluate hair loss because clinical appearance can be misleading and the diagnosis may change after closer examination. For androgenic alopecia, the key trichoscopic sign is hair shaft thickness heterogeneity caused by follicular miniaturization, along with features such as multiple one-hair units, numerous vellus hairs, and sometimes a peripilar sign, which may indicate a poorer prognosis. Several cases show how trichoscopy can reveal alternative diagnoses: one patient initially thought to have androgenic alopecia was actually found to have fibrosing alopecia in a pattern distribution, and another had frontal fibrosing alopecia, suggested by lack of thickness heterogeneity and vellus hairs plus scarring features. A difficult young patient with rapid hair loss was first considered for alopecia areata, but the trichoscopic pattern was ultimately more consistent with trichotillomania, supported by findings such as broken hairs, flame hairs, hair powder, V-sign, and trichoptilosis, later confirmed by further imaging. The talk emphasizes that alopecia areata and trichotillomania can share some trichoscopic signs, but alopecia areata usually shows many features across a wider field, whereas sparse isolated signs are not enough for diagnosis. Overall, the message is that trichoscopy is highly useful, but careful and sometimes repeated examination is necessary because appearances can be deceptive.