Mustafa Turhan Sahin
Scalp Dermoscopy or 'trichoscopy' represents a valuable, noninvasive technique for the evaluation of patients with hair loss. It allows for magnified visualization of the hair and scalp skin, and may be performed with a manual dermoscope or a videodermoscope. The usual working magnifications are 20-fold to 70-fold. Although the handheld dermoscope with 10-fold magnification may give easy and quick evaluation of hair, it does not precisely measure or document. Trichoscopy is a helpful tool in differential diagnosis of common acquired hair diseases, such as androgenetic alopecia, or diffuse alopecia areata. In androgenetic alopecia, hair diameter diversity, perifollicular pigmentation/peripilar sign and yellow dots trichoscopically observed. This method is simple, quick and easy to perform, reduces the need for scalp biopsy, is well accepted by patients, and is useful for monitoring treatment and followup. It represents a valuable link between clinical and histologic diagnosis. New data show that trichoscopy may easily replace light microscopic evaluation of pulled hairs in genetic hair shaft abnormalities. Features such as hair thickness, number of hairs in one pilosebaceous unit, or terminal to vellus hair ratio may be assessed. Visualization of hair follicle ostia allows identification of follicles that appear normal, empty, fibrotic (White dots in trichoscopy), filled with hyperkeratotic plugs (Yellow dots in trichoscopy), or containing cadaverized hairs (Black dots in trichoscopy). Abnormalities of scalp skin color and structure, which include honey-comb type hyperpigmentation, perifollicular discoloration, perifollicular fibrosis, and abnormal perifollicular microvessels, can also be visualized by trichoscopy. As it is important to consider various trichoscopic findings together to establish the diagnosis of different hair and scalp diseases, characteristic trichoscopic features of each of them will be discussed in this presentation.
