How long do I cool a burn for, and when does it need A&E?
Twenty minutes of cool running water, within three hours, and nothing else on it. The categories that always need A&E, and why chemical and electrical burns are different problems.
- Difficulty
- beginner
- Time
- 7 min
- Read
- 5 min
- Safety
- warning
Short answer
Cool the burn under cool running water for 20 minutes, as soon as you can and within 3 hours. Remove clothing and jewellery near the burn, but not anything stuck to it. Once cooled, lay cling film over it — do not wrap it around. No creams, oils, butter or plasters. A&E for burns that are large or deep, on the face, genitals or bottom, or caused by a chemical or electricity.
Twenty minutes is far longer than almost anyone cools a burn for, and it is the single thing that most changes how a burn heals. The rest of the advice is mostly about what not to put on it, because the folk remedies are all worse than nothing.
Safety
Step by step
- Stop the burning first.Get the person away from the heat source. Smother flames. Turn off the power before touching anyone who is in contact with electricity. For a chemical, brush off any dry powder before rinsing, and protect yourself.
- Cool it under running water for twenty minutes.Cool running water, not cold and not ice. NHS advice is 20 minutes, done as soon as possible and within 3 hours of the injury. Set a timer, because everyone stops early.
- Remove clothing and jewellery near the burn.Rings, watches and anything constricting come off before swelling starts. Do not remove anything that is stuck to the burn — leave that to the hospital.
- Keep the person warm while cooling the burn.Twenty minutes of running water cools the whole person too, particularly a child or an older adult. Cover the rest of them with a blanket or a coat while the burn stays under the water.
- Cover it with cling film once cooled.Lay the film over the burn rather than wrapping it around, so there is no constriction if it swells. A clean plastic bag works for a hand or a foot. It keeps the burn clean and it dramatically reduces the pain.
- Put nothing else on it.No creams, oils, butter, toothpaste, or ice. NHS advice is explicit about creams, oils and butter, and none of the folk remedies help — several make assessment harder and some cause further injury.
- Know the burns that always need A&E.Large or deep burns. Any burn on the face, genitals or bottom. Any burn caused by acid or another chemical. Any burn caused by electricity. All of these need assessment regardless of how they look.
- Treat a chemical burn as an ongoing injury.A chemical keeps damaging tissue until it is removed, so irrigation is prolonged rather than twenty minutes. Take the container or a photograph of the label with you, and keep rinsing while help is on the way.
- Treat an electrical burn as more than a burn.Current passing through the body can damage tissue along its path and affect the heart, so an electrical injury needs assessment even where the visible burn is small. Do not approach anyone still in contact with a supply until the power is confirmed off.
Tips
- A burn that blisters is at least partial thickness. Do not burst blisters — they are a sterile dressing the body made.
- For a child, a burn larger than the palm of their own hand is a reasonable trigger for getting it looked at, and any scald from a hot drink to a small child is worth a professional opinion.
- Sunburn is a burn. GuideHQ has a guide on treating it, and severe sunburn with blistering or systemic symptoms deserves the same seriousness as any other burn.
Common mistakes
- Cooling for two minutes — Twenty is the number in the guidance and the difference in outcome is real. Heat continues damaging tissue after the source is removed, and cooling is what stops it.
- Using ice or very cold water — It causes further tissue damage and constricts blood supply to an area that needs it. Cool running water is the instruction.
- Putting butter, cream or toothpaste on it — None of them help, they trap heat, they contaminate the wound and they have to be removed before the burn can be assessed.
- Wrapping cling film tightly around a limb — A burn swells. Film wrapped around a limb becomes a constriction. Lay it on rather than winding it.
If it doesn't work
The burn looks white, leathery or charred, or does not hurt
Cause: A deep burn — nerve endings may have been destroyed — Fix: Painless is not good news here. Cool it and go to A&E, or ring 999 for anything large.
A scald under clothing
Cause: Hot liquid soaking into fabric, which holds the heat against the skin — Fix: Get the clothing off unless it is stuck, then cool for 20 minutes. Fabric holding hot liquid against skin keeps burning after the spill.
A burn from a chemical is still stinging after rinsing
Cause: Chemical remaining on or in the tissue — Fix: Keep rinsing with running water and get help. Do not attempt to neutralise a chemical with another chemical — the reaction generates heat and makes it worse.
Questions people ask
Is it too late to cool a burn?
NHS advice is to cool as soon as possible and within 3 hours of the injury, so a delay does not mean there is no point. Cool it anyway.
Should I burst a blister?
No. An intact blister is a sterile cover. If it bursts on its own, keep the area clean and covered, and see a pharmacist or a nurse if it is large or in an awkward place.
What about a burn in the mouth or throat?
Airway burns are an emergency — from hot drinks in small children, from steam, or from smoke in a fire. Ring 999. Swelling in an airway develops over hours and it is not something to watch at home.
Do I need a tetanus jab for a burn?
Burns are not the classic tetanus wound, but a contaminated or deep injury raises it. Ask when you are seen, or ask a pharmacist or NHS 111 if you are unsure of your vaccination history.