Trichoscopy 101 for Alopecia Diagnoses

Conclusions

• Trichoscopy is a useful diagnostic tool for hair loss, allowing differentiation between scarring and non-scarring alopecia.
• Non-scarring hair loss can be categorized as patchy or diffuse, with specific features associated with conditions like alopecia areata, trichotillomania, and tinea capitis.
• In alopecia areata, characteristic features include constrictions in hair shafts, broken hairs, and the presence of yellow dots and exclamation mark hairs.
• Trichotillomania is identified by broken hairs of varying lengths, resulting from patients pulling their hair.
• Tinea capitis presents with corkscrew and comma-shaped hairs, along with morse code hairs, indicating fungal infection.
• Androgenetic alopecia is indicated by hair shaft diameter diversity, especially when over 20% of hairs are thin.
• Acute telogen effluvium diagnosis is based on clinical history, but may present with short regrowing hairs during early stages.
• In scarring alopecias, the loss of follicular openings is a hallmark feature observed through trichoscopy.
• Lichen planopilaris and discoid lupus exhibit specific trichoscopic features like scaling patterns and pigmentation changes, with inflammatory responses differing in follicular centricity.
• Frontal fibrosing alopecia is characterized by perifollicular scaling and absence of vellus hairs at the hairline.
• Dissecting cellulitis shows changes in trichoscopy reflective of disease progression, with features like black dots and pustules at different stages.