Androgenetic Alopecia: Medical and Surgical Options

Overview / Definition Androgenetic alopecia (AGA), often referred to as male or female pattern baldness, is a hereditary condition that leads to hair thinning and loss. It is characterized by a progressive decrease in the size of hair follicles, resulting in shorter and finer hair strands. In men, it typically presents as a receding hairline and thinning at the crown, while in women, it manifests as diffuse thinning over the crown and widening of the part. Epidemiology AGA is one of the most prevalent forms of hair loss, affecting up to 50% of men and 40% of women by the age of 50. The condition often begins in the late teenage years to early twenties in men and typically presents later in women, often after menopause. Prevalence increases with age. Genetic predisposition plays a significant role. Equal distribution across races, though patterns may vary. Pathophysiology / Mechanism The pathophysiology of AGA involves a complex interplay between genetic susceptibility and hormonal influences, particularly androgens such as testosterone and its derivative dihydrotestosterone (DHT). These hormones lead to miniaturization of hair follicles and a shortening of the anagen phase of the hair cycle. DHT binds to androgen receptors in the hair follicles. Follicles undergo progressive miniaturization. Increased levels of inflammatory cytokines may exacerbate hair loss. Clinical Presentation In men, AGA typically presents with a receding hairline and thinning at the crown, following the Norwood-Hamilton classification. Women usually experience diffuse thinning across the scalp, particularly over the crown, following the Ludwig classification. Men: Stage I: No significant hair loss. Stage II: Receding hairline. Stage III: Thinning at the crown. Women: Type I: Mild thinning. Type II: Moderate thinning. Type III: Severe thinning and widening of the part. Diagnosis / Workup The diagnosis of AGA is primarily clinical, based on the characteristic patterns of hair loss. Additional wo