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This is a clinician-written, evidence-based summary aligned to the 2026 MLA Content Map. It is intended for medical students and junior doctors preparing for the UKMLA. Always cross-reference with NICE guidance, local protocols, and clinical judgement.
Key points
- Non-scarring (follicles preserved): alopecia areata, androgenetic, telogen effluvium, traction
- Scarring (follicles destroyed, irreversible): lichen planopilaris, discoid lupus, frontal fibrosing
- Alopecia areata: smooth round patches + "exclamation mark" hairs. Autoimmune
- Androgenetic: commonest overall. Male (bitemporal + vertex) or female (diffuse thinning)
- Telogen effluvium: diffuse shedding 2-4 months after trigger (post-partum, illness, stress)
Overview
Key distinction: non-scarring (follicles preserved, potentially reversible) vs scarring (follicles destroyed, irreversible). Non-scarring: alopecia areata (autoimmune), androgenetic (hormonal/genetic), telogen effluvium (reactive shedding), traction, tinea capitis. Scarring: lichen planopilaris, discoid lupus, frontal fibrosing alopecia.
Epidemiology
Androgenetic: ~50% of men >50, ~50% of women >65. Alopecia areata: ~2% lifetime risk. Telogen effluvium very common, especially post-partum. Alopecia areata associated with vitiligo, thyroid disease, T1DM.
Clinical Features
Symptoms
Alopecia areata: well-demarcated smooth round patches with exclamation mark hairs
Androgenetic male: bitemporal recession + vertex thinning
Androgenetic female: diffuse thinning with preserved frontal hairline
Telogen effluvium: diffuse shedding 2-4 months after trigger
Scarring: permanent loss with visible scarring, absent follicular ostia
Rapidly progressive total hair loss (alopecia totalis/universalis)
Signs
Exclamation mark hairs: short tapered hairs at patch periphery (AA)
Scarring: loss of follicular ostia, skin atrophy within patch
Tinea capitis: scaling, broken hairs in children — always consider
Investigations
First-line
Clinical diagnosis + trichoscopyExclamation mark hairs, black dots (AA). Loss of follicle openings (scarring)
Second-line
BloodsTFTs, ferritin, FBC, vitamin D — screen for treatable causes
Scalp biopsyIf uncertain — essential to distinguish scarring from non-scarring
Fungal scrapingIf tinea capitis suspected in children
Management
BAD Guidelines + NICE CKS1
Alopecia areata
- Mild: watchful waiting — 80% regrows within 1 year
- Potent topical corticosteroid or intralesional triamcinolone
- Extensive: specialist — topical immunotherapy (DPCP), JAK inhibitors (baricitinib, NICE TA958)
- NHS wig provision
2
Androgenetic
- Male: topical minoxidil 5% BD or oral finasteride 1 mg OD
- Female: topical minoxidil 2-5%. Spironolactone off-label via dermatology
- Hair transplantation for stable disease
3
Telogen effluvium
- Identify and address trigger
- Reassurance: resolves 3-6 months once trigger removed
- Correct iron deficiency (aim ferritin >70), check TFTs
4
Scarring alopecia
- Urgent dermatology referral — early treatment halts progression
- Potent topical/intralesional steroids, hydroxychloroquine
- Hair lost to scarring does NOT regrow
Complications
- Psychological impact: Significant distress, anxiety, depression
- Alopecia totalis/universalis: ~5% of AA
- Permanent loss: Scarring alopecia is irreversible
UKMLA Exam Tips
- 1Exclamation mark hairs = alopecia areata — pathognomonic
- 2Non-scarring: follicles visible, reversible. Scarring: follicles absent, irreversible
- 3Telogen effluvium: diffuse shedding 2-4 months AFTER trigger
- 4Finasteride: contraindicated in women of childbearing potential (teratogenic)
- 5Children with hair loss + scaling = consider tinea capitis — take scraping
- 6Nail pitting in AA and psoriasis — but smooth bald patches = AA
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