The deceptive injury

Most bangs on the head amount to nothing more than a bruise and a bad mood. The problem is the small minority that do not — because a bleed inside the skull can build slowly while the injured person walks, talks and insists they are fine. Someone can seem completely themselves for hours before deteriorating. That is why head injuries get their own rulebook: the decision is based less on how the person looks right now and more on what happened, who they are, and which symptoms appear over time.

This guide gives you that rulebook.

Call 999 now if any of these apply

Do not drive them yourself, do not wait to see how things develop — phone an ambulance if the person:

  • Was knocked out, even for a moment, and is now hard to rouse, confused or drowsy
  • Has a fit or convulsion
  • Has straw-coloured or clear fluid, or fresh blood, coming from an ear or the nose
  • Develops weakness down one side, slurred speech, or trouble understanding you
  • Has unequal pupils, a visible dent in the skull, or a soft, squashy swelling rather than an ordinary hard lump
  • Keeps vomiting
  • Was hurt in a high-force way — a road collision, a fall from well above head height, an assault with a weapon

If they are unconscious but breathing, put them on their side in the recovery position — unless the mechanism suggests a neck injury (a dive into shallow water, a fall from height, neck pain or limb tingling), in which case keep the head and neck still and let the call handler guide you. Our 999 guide covers what to expect on the call.

Get to A&E today — by car or taxi is fine

A trip to the emergency department, without an ambulance, is the right move when the person:

  • Blacked out briefly but has come round fully
  • Cannot remember the accident itself, or the minutes before or after it
  • Has vomited since the injury (once is enough to earn a check)
  • Has a headache that is climbing rather than fading, despite paracetamol
  • Takes any blood-thinning medicine — warfarin, apixaban, rivaroxaban, edoxaban, dabigatran, clopidogrel or similar. This point is non-negotiable: on these drugs, even a trivial-looking bump can bleed inside the skull, and every such injury needs same-day assessment
  • Is over 65, has had brain surgery in the past, or has a clotting disorder
  • Was drinking heavily or has taken drugs — intoxication masks the very symptoms you are watching for

Never let someone with a head injury drive themselves. If you are choosing between departments, live waiting times can help — but with any of the signs above, nearest beats quietest.

When home is safe — and how to keep watch

Plenty of head injuries genuinely need nothing more than a cold flannel and sympathy. Home is reasonable when the knock was minor (a doorframe, a low cupboard), there was no blackout, no memory gap, no vomiting, the person is behaving entirely normally, and nobody involved takes blood thinners.

Even then, keep a watch running for 48 hours, because delayed deterioration is the whole danger with heads:

  • Someone responsible should stay with the person for the first day — do not leave them alone in the house overnight
  • Overnight, check on them every two to three hours: they should rouse easily and answer sensibly. Groggy is fine; unrousable is 999
  • No alcohol, no sleeping tablets, and no driving or big decisions for 48 hours — reactions and judgement dip even after mild concussion
  • Paracetamol is the painkiller of choice at first; avoid ibuprofen and aspirin in the first day or so unless a clinician says otherwise, as they can slightly increase bleeding

Return immediately — day or night, our overnight care guide confirms A&E never closes — if drowsiness deepens, vomiting starts, the headache turns severe, vision doubles or blurs, behaviour turns strange or irritable, limbs weaken, or fluid appears from the nose or an ear.

Babies and children

Small children collect head bumps as a hobby, and the vast majority are trivial. Still, they deserve extra caution: an infant's skull is thin, and a baby cannot tell you about blurred vision or a pounding head. Take a child to A&E if they were knocked out at all, have vomited more than once, fell further than their own height onto something hard, have a large boggy swelling (as opposed to the classic hard "egg"), seem unusually sleepy or floppy, will not settle despite every trick you know, or — for babies — are refusing feeds. Under-ones with anything beyond the gentlest bump should simply be checked. There is more on the practicalities in our guide to taking a child to A&E.

Older adults: a special warning

The over-65s face a double risk. First, blood thinners are common at this age, and they transform the arithmetic of even minor bumps. Second, a type of slow bleed (a subdural haematoma) can develop over days or even weeks in older people — so a fall in the garden a fortnight ago can be the cause of today's new confusion, unsteadiness or personality change. If an older relative has "not been right" since a fall, do not put it down to age: get them assessed, and mention the fall. Our guide on older adults in A&E covers how to advocate for them once you are there.

What the hospital will actually do

After triage, a clinician runs a neurological examination — pupils, limb strength, balance, memory, orientation. NHS departments follow national criteria for who needs a CT scan of the head: things like loss of consciousness, amnesia, repeated vomiting, blood thinners, age, and the force involved all feed into that decision, and the scan usually happens within an hour or so of it being requested. A clear scan plus a period of observation generally means home with a written head-injury advice sheet; a bleed or fracture means admission, occasionally with transfer to a neurosurgical centre. Bring a list of medications — the anticoagulant question is the single most important thing the team needs to know.

Concussion: the weeks after

If the diagnosis is concussion, expect headaches, fogginess, tiredness, poor concentration and sensitivity to light or noise for a week or two. Recovery works best as a staircase: a couple of days of genuine rest, then a gradual return to normal life as symptoms allow, easing off whenever they flare. Two hard rules: no alcohol until recovered, and absolutely no return to rugby, football, boxing, riding or any collision sport until symptom-free and through a graduated return — a second concussion on top of an unhealed first one can be catastrophic. Symptoms dragging past two to three weeks warrant a GP review.

The short version

  • Head injuries can look fine and then go wrong — judge by red flags and risk factors, not appearances
  • 999 for unconsciousness with drowsiness, fits, fluid from ears or nose, one-sided weakness or repeated vomiting
  • Same-day A&E for any blackout, memory gap, single vomit, worsening headache — and always for anyone on blood thinners, however small the bump
  • Watch minor injuries at home for 48 hours, with overnight checks and zero alcohol
  • Extra caution with babies, and with older people who "haven't been right" since a fall
  • Find your nearest emergency department — and remember it is open at 3 am too