Androgenetic alopecia
Androgenetic alopecia is an androgen-dependent, nonscarring hair loss pattern in men and women that begins after puberty, presenting as bitemporal recession with vertex balding in men and part-line widening at the crown in women. Diagnosis is clinical from the distribution, and first-line treatment is topical minoxidil 5% for both sexes, with oral finasteride 1 mg daily an additional approved option for men.
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What this article covers
- Overview
Definition: androgenetic alopecia is an androgen-dependent, nonscarring pattern of hair loss that affects both men and women, with onset typically after puberty and a gradual, progressive course.
- Epidemiology
Nearly universal with age: androgenetic alopecia is the most common cause of hair loss in both sexes and becomes progressively more prevalent through adulthood.
- Risk factors
Genetic predisposition: family history of pattern hair loss in either parent's lineage is the dominant risk factor, consistent with the androgen-receptor-dependent, heritable nature of the condition.
- Pathophysiology
DHT-driven miniaturization: testosterone is converted to dihydrotestosterone (DHT) by type 2 5-alpha-reductase, and DHT binds androgen receptors in genetically susceptible scalp follicles.
- Clinical features
Diagnostic pattern in men: bitemporal hairline recession that progresses to vertex balding is the defining presentation and, together with the history, is usually sufficient to establish the diagnosis.
- Differential diagnosis
Alopecia areata: well-circumscribed, smooth, oval patches of hair loss with short "exclamation point" hairs at the rim, unlike the diffuse regional thinning of androgenetic alopecia.
- Diagnosis
Clinical diagnosis from the pattern establishes the diagnosis first: bitemporal-to-vertex thinning in a man, or crown part-widening in a woman, with a gradual onset and a family history, is typically sufficient without further testing.
- Management
First-line for both men and women: topical minoxidil 5% solution or foam, apply 1 mL to the scalp twice daily; continue for at least 3 months before assessing effect, and continue indefinitely, since benefit is lost after discontinuation.
- Complications
Loss of gained hair after stopping treatment: discontinuing either topical minoxidil or oral finasteride reverses the accumulated benefit within about 12 months, effectively returning the patient to the untreated trajectory.
- Prognosis
Chronic and progressive without treatment: androgenetic alopecia does not spontaneously reverse, and thinning continues gradually over years in genetically susceptible individuals.
- Prevention
Earlier initiation preserves more follicles: starting topical minoxidil (and, in men, finasteride) while thinning is still early and follicles remain viable is more effective at preserving existing…
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