Male pattern hair loss (male androgenetic alopecia)
Exam Tips
- In OSCEs, emphasize patterned, gradual, non-scarring loss (bitemporal + vertex) as the key diagnostic triad.
- A diffusely positive hair pull test should prompt search for telogen effluvium even if androgenetic alopecia is present.
- State that normal serum testosterone does not exclude diagnosis; follicular sensitivity to DHT is central.
- Quote realistic timelines: minoxidil often needs 2-4 months for visible change; finasteride commonly 3-6 months to stabilization.
- Always mention safety counselling for finasteride (sexual and psychiatric adverse effects, PSA interpretation, teratogenic handling warning).
Definition
Male pattern hair loss (male androgenetic alopecia) is a common, non-scarring alopecia in which scalp hair progressively thins in a characteristic androgen-dependent distribution, usually starting with bitemporal recession and vertex thinning. It is a chronic, genetically influenced condition driven by follicular sensitivity to dihydrotestosterone rather than markedly raised circulating androgens, and severity is commonly staged with the Hamilton-Norwood scale.
Pathophysiology
Hair follicles cycle through anagen (growth), catagen (involution), and telogen (rest). In genetically susceptible men, follicular androgen signalling (especially via dihydrotestosterone formed by 5-alpha-reductase) shortens anagen duration and causes progressive miniaturization of terminal follicles into vellus-like follicles. Over successive cycles, hairs become finer, shorter, and less pigmented, telogen proportion rises, shedding becomes more apparent, and regrowth latency increases, producing visible patterned thinning. Most affected men have normal serum androgen concentrations; the key abnormality is local follicular sensitivity (for example increased androgen receptor activity and/or 5-alpha-reductase activity).
Risk Factors
- Positive family history (strongest predictor; polygenic inheritance from either parent)
- Increasing age after puberty
- Early-onset thinning (late teens/20s) associated with faster and more extensive progression
- White ethnicity has higher lifetime incidence than some other ethnic groups
Clinical Features
Symptoms
- Gradual, patterned hair thinning rather than sudden patchy loss
- Perceived increased shedding (often intermittent periods of acceleration)
- Psychological distress (reduced self-esteem, embarrassment, social withdrawal)
- Usually no scalp pain or itch; symptoms suggest alternative diagnoses if present
Signs
- Bitemporal recession with frontal/vertex thinning and preserved occipital/parietal fringe until late disease
- Miniaturized finer hairs in affected regions with reduced density
- Typically no scalp erythema, scale, pustules, scarring, or broken hairs
- Hair pull test usually negative in classic androgenetic alopecia (may be mildly positive in active areas)
- Severity graded by Hamilton-Norwood stages I-VII (see standard Hamilton-Norwood figure/diagram used in dermatology texts)
Investigations
Management
Lifestyle Modifications
- Provide realistic counselling: treatment slows loss and may regrow some hair, but complete reversal is unlikely
- Explain timelines to improve adherence (benefit often appears after months, not weeks)
- Address psychosocial impact proactively; offer support for anxiety/depressed mood and discuss cosmetic options (hairstyle adaptation, camouflage fibres, shaving, wigs/hairpieces)
- Advise scalp photoprotection (hat/sunscreen on exposed scalp) due to reduced UV protection
Pharmacological Treatment
Topical vasodilator
- Minoxidil 5% topical solution or foam: apply 1 mL to affected scalp twice daily (men)
Available without prescription in UK. Continue long term to maintain effect; initial increased shedding can occur. Typical response after 2-4 months, maximal around 12 months. Adverse effects: scalp irritation/contact dermatitis, headache, hypertrichosis; rare systemic hypotension/tachycardia. Avoid application to inflamed/infected scalp and wash hands after use.
5-alpha-reductase inhibitor
- Finasteride 1 mg orally once daily (men aged 18-41 years in UK product licence)
Can reduce progression and improve density; assess response after 6-12 months and continue if beneficial. Safety: sexual dysfunction (reduced libido, erectile/ejaculatory problems), breast tenderness/enlargement, mood changes including depression/suicidal ideation; advise prompt review if psychiatric symptoms occur. Finasteride lowers PSA (roughly halves values), which can complicate prostate cancer screening interpretation. Contraindicated in women; crushed/broken tablets should not be handled by pregnant women due to risk to male fetus.
Surgical / Interventional
- Hair transplantation (follicular unit transplantation/extraction) in selected stable disease after specialist assessment
Complications
- Psychological morbidity (low self-esteem, social avoidance, reduced quality of life, mood symptoms)
- Progressive cosmetic hair loss with variable speed and extent
- Greater scalp vulnerability to sunburn/cold/mechanical trauma in advanced loss
Prognosis
Untreated disease usually progresses, but the rate is highly variable: some men retain substantial hair while others develop extensive baldness over years (occasionally rapidly). Earlier onset generally predicts greater lifetime severity. Continuous treatment can slow progression and produce partial regrowth, but benefit is treatment-dependent and typically wanes within months of stopping (often returning toward baseline by about 9-12 months).
Sources & References
✅NICE Guidelines(1)
📖Textbook References(4)
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1224)[context]
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1684)[context]
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1684)[context]
- Guyton and Hall Textbook of Medical Physiology (John E. Hall, Michael E. Hall) (Z-Library).pdf(pp. 1007)[context]