Hair Loss: Diagnosis and Treatment.

More than 80 million people in the United States are affected by hair loss, also known as alopecia. Nonscarring alopecias are categorized as diffuse, patterned, or focal. Diffuse alopecias include telogen and anagen effluvium, are usually self-limited, and depend on stopping the underlying cause (e.g., stress). Patterned hair loss, specifically androgenetic alopecia, is the most common form of alopecia; it is typically genetic, and first-line treatment is minoxidil. Oral finasteride is another treatment available for male patients. Focal hair loss includes alopecia areata, which is typically self-limited and treated with intralesional corticosteroid or oral immunosuppressant therapy; tinea capitis, which is treated with oral antifungals; and traction alopecia, which is treated by decreasing tension on the hair. Hair loss can be caused by several systemic diseases. A comprehensive history and physical examination, with targeted laboratory testing, may elucidate malnutrition, autoimmune diseases, and endocrine disease. Patients with moderate to severe hair loss are more likely to have accompanying anxiety, depression, and lower work productivity and quality-of-life scores. Educating patients about expected hair changes, treatment options, and realistic outcomes can help patients feel that they are being listened to and that their hair loss is being taken seriously.