ABSTRACT
Hair shaft thickness heterogeneity, also known as “anisotrichosis”, is the most common trichoscopic feature of androgenetic alopecia. In advanced androgenetic alopecia, non-specific trichoscopic findings such as white dots and honeycomb pattern can be detected. Classic, big, irregular white dots that represent areas of perifollicular fibrosis and small regular, pinpoint white dots that correspond to hair follicle openings and eccrine sweat gland openings. White dots are mainly presented in severe, long-lasting androgenetic alopecia and thus considered as poor prognostic factors. Yellow dots correspond to follicular infundibula filled with sebum and/or keratotic material. In alopecia areata, yellow dots are characterized by an abundant amount and regular distribution. Exclamation mark hairs are fractured hairs with a thin, usually hypopigmented, proximal end and a significantly thicker distal end that is commonly hyperpigmented. Tapered hairs represent elongated exclamation mark hairs with a thinner proximal end and the distal end outside of the field of view of a dermoscope.
