Synopsis
Distinguish patterned follicular miniaturisation from reactive diffuse shedding, investigate only supported causes, and counsel accurately on minoxidil, finasteride, recovery times and safety.
- Androgenetic alopecia is gradual patterned miniaturisation: frontal and vertex recession is typical in male-pattern loss, while female-pattern loss often widens the central part with relative frontal-hairline preservation.
- Telogen effluvium is diffuse shedding after many follicles synchronously enter rest, often two to three months after fever, surgery, childbirth, major psychological stress, dietary restriction or a medicine change.
- Pattern loss and telogen effluvium can coexist; a shedding episode may reveal previously subtle miniaturisation rather than creating permanent follicle destruction.
- Ask about onset, tempo, shedding versus thinning, pregnancy, illness, weight change, diet, menstruation, medicines, family pattern and hair practices before ordering tests.
- Examine scalp and follicular openings, compare shaft diameters with dermoscopy and perform a standardised hair pull; inflammation or scarring overrides an ordinary pattern diagnosis.
- Full blood count, ferritin and thyroid function are selected from diffuse-loss history and clinical risk; normal results do not justify repeated supplements or broad endocrine panels.
- Licensed topical minoxidil can slow patterned loss but requires continued use, may cause early shedding and scalp irritation, and must not be applied in pregnancy or to inflamed skin.
- Oral finasteride 1 mg is licensed for male-pattern hair loss in eligible men; discuss sexual and psychiatric adverse effects, pregnancy handling and the MHRA patient alert before prescribing.
- Acute telogen effluvium commonly recovers after its trigger resolves, but shedding can continue for months and visible density lags behind renewed growth.
Key red flags
Loss of follicular openings, scalp pain or scale, pustules, rapid virilisation, a scalp mass, systemic illness, profound nutritional compromise or hair loss in a child requires an alternative and sometimes urgent specialist pathway.
Smooth patches, broken hairs of uneven length, perifollicular scale, pustules or missing openings require alopecia areata, trauma, fungus or scar assessment.
Investigation priorities
Identify distribution, shaft miniaturisation, regrowth and inflammatory or scarring signs.
Management branches
Hair is shedding from the whole scalp without obvious scar or focal inflammation.
- Map onset against illness, operation, childbirth, medicines, menstruation, dietary restriction and psychological stress during the preceding two to four months.
- Examine for patterned miniaturisation and regrowth, then request full blood count, ferritin, thyroid or other tests only where history creates a plausible corrective action.
- Treat the identified cause, support adequate nutrition and review over six to twelve months, explaining that shedding and visible density recover on different timelines.
Key medicines
Minoxidil 5% foam for licensed male-pattern useApply half a capful to the dry affected scalp twice daily, do not exceed a total of two capfuls daily, and wash hands afterwards.Use only on a healthy scalp and stop for chest pain, faintness, tachycardia, oedema or persistent irritation. Avoid pregnancy and breastfeeding, prevent transfer to other skin and keep away from flame while wet.
Minoxidil 5% foam for licensed female-pattern useApply half a capful to the dry affected scalp once daily, allow it to dry fully and wash hands after application.Exclude sudden unexplained loss and scalp inflammation first. Avoid pregnancy and breastfeeding; counsel about early shedding, unwanted facial hair, irritation and loss of benefit after discontinuation.