Trichoscopy: Dermoscopy of Hair and Scalp

Overview / Definition Trichoscopy is a dermoscopic technique specifically tailored for evaluating the hair and scalp. Using a handheld dermatoscope or digital dermatoscope, clinicians can visualize hair follicles, hair shafts, and the scalp's surface architecture, revealing details not visible to the naked eye. This technique is particularly useful in diagnosing alopecia and other hair disorders by providing a magnified view of skin and hair structures. Epidemiology The prevalence of hair disorders varies widely, with conditions such as androgenetic alopecia affecting up to 50% of men and women by the age of 50. Other common conditions diagnosed using trichoscopy, such as alopecia areata, have a lifetime prevalence of approximately 2%. Understanding the epidemiological context of hair disorders is crucial for dermatologists in recognizing and managing these conditions effectively. Pathophysiology / Mechanism Trichoscopy allows for the visualization of hair follicle anatomy, including the anagen, catagen, and telogen phases of hair growth, as well as the presence of inflammation, scarring, or dystrophic changes. Conditions such as alopecia areata are thought to be autoimmune in nature, where the immune system attacks hair follicles, leading to hair loss. Other conditions like telogen effluvium are often linked to systemic stressors that push hair follicles into the telogen phase prematurely. Clinical Presentation Patients may present with a variety of symptoms depending on the underlying condition. Common complaints include: Hair loss: Gradual or sudden, localized or diffuse. Itching or irritation: Often associated with inflammatory conditions. Changes in hair texture: Thinning, brittleness, or increased shedding. Upon examination, specific findings can be noted: Exclamation mark hairs: Indicative of alopecia areata. Yellow dots: Often seen in androgenetic alopecia. Pigmentary changes: Suggesting scarring alopecia. Diagnosis / Workup The diagnostic approach begins wi