Ferrybridge Medical Centre

8-10 High Street, Ferrybridge, West Yorkshire, WF11 8NQ

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Dealing with the Effects of Heat

Dealing with the Effects of Heat

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This leaflet is created from first aid advice provided by St John Ambulance, the nation's leading first aid charity. This advice is no substitute for first aid training - find a training course near you.

Burns and scalds are damage to the skin caused by heat. A burn is usually caused by dry heat, like fire, a hot iron, or the sun. A scald is caused by wet heat, like steam or a hot cup of tea.

You need to be extra careful when treating burns. The longer the burning goes on, the more severe the injury will be, and the longer it may take to heal. So you need to cool the burn as soon as possible.

If someone has a severe burn or scald they are likely to suffer from shock, because of the fluid loss, so they will need urgent hospital treatment.

What to look for

If you think someone has a burn or scald, there are five key things to look for: 

  1. Red skin.
  2. Swelling.
  3. Blisters may form on the skin later on.
  4. The skin may peel.
  5. The skin may be white or scorched. 

What to you need to do

Stop the burning getting any worse, by moving the casualty away from the source of heat.

Start cooling the burn as quickly as possible. Run it under cool water for at least ten minutes or until the pain feels better. (Don't use ice, creams or gels - they can damage tissues and increase risk of infection).

Assess how bad the burn is. It is serious if it is: 

  • Larger than the size of the casualty's hand.
  • On the face, hands or feet.
  • Or a deep burn. 

If it is serious, call 999 or 112 for emergency medical help.

Remove any jewellery or clothing near the burn (unless it is stuck to it).

Cover the burned area with kitchen cling film or another clean, non-fluffy material, like a clean plastic bag. This will protect from infection.

If necessary, treat for shock (shock is a life-threatening condition, not to be confused with emotional shock).

If you are unsure if the burn is serious then tell the person to see a doctor.

Heat rash is an itchy rash of small red spots that cause a stinging or prickling feeling on the skin. Sometimes it's called prickly heat.

The heat rash can be anywhere on the body, but typically people get it on their face, chest, back and thighs.

It is caused by sweat glands becoming blocked, so people usually get the rash if they are sweating more than usual. This could be because of hot or humid weather or because they're wearing too many clothes, which irritate the rash more by rubbing it. The trapped sweat irritates the skin and produces the rash.

Heat rash is not serious. It usually goes away after a few days so it doesn't need medical treatment.

What to look for

If you think someone has heat rash, these are the four things to look for: 

  • Itching.
  • Rash of tiny red spots.
  • Mild swelling.
  • Prickling or burning feeling. 

What you need to do 

  • If they have these symptoms, you can explain that the rash is not serious but give them tips on how to soothe the itching and avoid getting heat rash in the future.
  • Suggest they take a cold bath or shower to cool their skin and help prevent further sweating.
  • They can also buy calamine lotion or hydrocortisone cream which will help soothe the itching.
  • Recommend they wear loose clothing made of cotton, as cotton doesn't trap heat as much as synthetic fibres, like nylon and polyester.
  • Tell them to drink plenty of water to stop them getting dehydrated.
  • And suggest they avoid excessive heat or humidity, by staying out of the sun and not sitting too close to a fire or heater, for instance. 

Sunburn is caused by too much exposure to the sun or a sun lamp. At high altitudes, people can get sunburnt even when it's cloudy or snowing.

Some medicines can trigger severe sensitivity to sunlight. Sunburn can also be caused by exposure to radioactivity, though this is extremely rare.

The best way to avoid getting sunburn is to avoid too much exposure to the sun, by covering up with clothing or sun cream.

Most sunburn is not serious. In severe cases though, the skin can turn lobster red in colour and blister.

What to look for

These are the three things to look for:

  1. Reddened skin.
  2. Pain in the area of the burn.
  3. Blistering.

What you need to do 

  • First, cover their skin with lightweight clothing and move them out of the sun and into the shade, or indoors if possible.
  • Encourage them to keep taking sips of cold water.
  • Cool the skin by sponging it gently with cool water, or by soaking the sore skin in a cold bath or shower for no more than ten minutes. Repeat this if it helps ease soreness.
  • If the burn doesn't blister, then it is mild. Apply calamine lotion or after-sun lotion to help soothe the skin.
  • If the burn blisters or there is other skin damage, then it is severe and they'll need to see a doctor.
  • Also watch out for and treat symptoms of heatstroke or heat exhaustion, which can be life threatening. 


Heatstroke is caused by a failure of the thermostat in the brain which regulates the body temperature. If someone has a high fever or has been exposed to heat for a long time, then their body can become dangerously overheated.

Someone can also get heatstroke after using drugs such as ecstasy.

Sometimes, people get heatstroke after suffering from heat exhaustion. When someone gets too dehydrated they stop sweating which means their body can't cool down anymore, so they develop heatstroke.

Heatstroke can develop with very little warning, causing unresponsiveness within minutes of someone feeling unwell. Your priority is to cool them down as quickly as possible and get them to hospital.

What to look for

These are the six key things to look for:

  • Headache, dizziness and discomfort.
  • Restlessness and confusion.
  • Hot flushed and dry skin.
  • A fast deterioration in the level of response.
  • A full bounding pulse.
  • Body temperature above 40°C (104°F).

What you need to do

  • Quickly move them to a cool place and remove their outer clothing but ensure you maintain their dignity.
  • Then call 999/112 for an ambulance.
  • Wrap them in a cold wet sheet and keep pouring cold water over it until their temperature falls to at least 38°C (or 100.4°F). Measure this with a thermometer under their tongue or under their armpit.
  • If you can't find a sheet, fan them or sponge them down with cold water to keep them cool.
  • Once their temperature seems to have gone back to normal, replace the wet sheet with a dry sheet.
  • While waiting for help to arrive, keep checking their temperature, as well as their breathing, pulse and level of response.
  • If they start getting hot again, repeat the cooling process to lower their temperature.
  • If they lose responsiveness at any point, open their airway, check their breathing and prepare to treat someone who's become unresponsive.

Heat exhaustion

Heat exhaustion is caused by a loss of salt and water from the body, usually through excessive sweating.

It develops slowly and usually happens to people who aren't used to hot, humid weather. People who are unwell are more likely to get it, especially if they are suffering from vomiting and diarrhoea.

A dangerous and common cause of heat exhaustion is when the body produces more heat than it can cope with.

This can happen when someone takes a non-prescription drug, like ecstasy, which can stop the body from regulating its temperature properly. If someone gets hot and sweats a lot from dancing as well, they may get overheated and dehydrated, giving them heat exhaustion.

If treated quickly, someone suffering from heat exhaustion should start feeling better quickly. But if not treated, they could develop heatstroke which can lead to death.

What to look for

These are the six key things to look for:

  1. Headache.
  2. Dizziness and confusion.
  3. Loss of appetite and feeling sick.
  4. Sweating with pale clammy skin.
  5. Cramps in the arms, legs and stomach.
  6. Fast, weakening pulse and shallow breathing.

What you need to do

  • Help take them to a cool place and get them to lie down with their legs raised.
  • Then give them lots of water. You can also give them a sports drink like Lucozade® or an oral rehydration solution to help replace the salt and fluid they have lost by sweating.
  • Keep checking their breathing, pulse and level of response.
  • Even if they recover quickly, suggest they see a doctor.
  • If they seem to be getting worse, place them into the recovery position and call 999/112 for an ambulance.
  • While waiting, keep checking their breathing, pulse and level of response.

Note: these hints are no substitute for thorough knowledge of first aid. St John Ambulance holds first aid courses throughout the country.

Adapted from the St John Ambulance leaflets: burns and scalds, heat rash, sunburn, heatstroke and heat exhaustion. Copyright for this leaflet is with St John Ambulance.

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but makes no warranty as to its accuracy. Consult a doctor or other healthcare professional for diagnosis and treatment of medical conditions. For details see our conditions.

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St John Ambulance
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