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A fever is a body temperature of 38C or above in children, or above 37.5C in adults. Most commonly, it is caused by an infection, and it is not normally anything to be too concerned about. However, a severe fever may be a sign of something more serious that needs urgent medical attention.

In most cases, treating the underlying issue will usually cause the fever symptoms to disappear after a couple of days. You can check for a high temperature at home using a thermometer, which you can buy from many high street stores or pharmacies.

What is a fever?

A high temperature, or fever, is an immune response to bacteria, a virus, fungi, toxin or drugs. The Hypothalamus in your brain (which controls many of your body’s hormones and chemicals that help control different cells and organs) ups your body temperature as a way of fighting off the infection.

The normal temperature range for adults is 36.1 to 37.5 degrees centigrade. As we mentioned above, if you have a temperature above 37.5C, this would be considered to be in the fever temperature range and, in children, if their temperature is above 38C, they are considered to have a fever.

If you have a fever, or you are worried about fever symptoms in your child, our doctors can help.

Signs and symptoms of a fever in adults

The symptoms of a fever can be slightly different for each person. However, common things to look out for in adults include:

  • A high temperature
  • Headache
  • Shivering or shaking
  • Intermittent sweats
  • Skin being hot to the touch
  • Feeling dizzy or faint
  • Rapid heart rate
  • Weakness
  • Loss of appetite
  • Achy muscles
  • Eye pain
  • Dehydration
  • General weakness

A very high fever (above 40C) can sometimes result in convulsions or confusion. You should seek medical advice as soon as possible if you, or someone you are caring for, has a temperature this high or is showing these severe symptoms.

What causes a fever in adults?

There are many reasons your body temperature may rise. Some of the most common things that cause high fever in adults include:

  • Infections, such as a cold or flu
  • A side effect of a medication or illegal drugs
  • Blood clots
  • Hormone disorders
  • Extreme sunburn
  • Autoimmune disorders
  • Cancer
  • Food poisoning
  • Some inflammatory diseases, such as Crohn’s disease (IBD)

Fever in children

If you child or baby has a high fever, they may not be themselves. As well as a high temperature, symptoms can include:

  • Looking or feeling unwell
  • Fussiness
  • Feel sweaty, clammy or hot to touch
  • Lack of appetite
  • A cough or sore throat
  • Wheezy breathing
  • Earache
  • Vomiting
  • Diarrhoea
  • A rash

If you child has a fever and any of the following symptoms, seek urgent medical attention:

  • If they are younger than 3 months old and have a temperature higher than 38C
  • If they are between 3 and 6 months old and have a temperature higher than 39C
  • Will not stop crying
  • Has swollen limbs
  • Is vomiting
  • Is showing signs of dehydration
  • Has cool hands and feet
  • Wheezy or more rapid than normal breathing

If your child has a fever and any of these symptoms you should dial 999 or go straight to A&E:

  • Is unresponsive, or drowsy
  • Is having seizures or fits
  • Has a stiff neck
  • Does not like bright lights
  • Has a rash that does not disappear when you roll a glass over it – this could be a sign of meningitis and needs urgent attention
  • The soft spot on the top of their head is bulging
  • Are drowsy or you are unable to wake them
  • Has pale, mottled skin
  • Is struggling with their breathing and you can see the skin sucking in beneath or between their ribs
  • Has a weak sounding high pitched cry very different to their normal cry

A fever in children may be caused by:

What should you do if you have a fever?

When you have a high temperature, you do not usually need to treat the fever itself, but the underlying problem, such as an infection, needs to be treated instead. As we mentioned earlier, usually it is nothing to worry about and should pass in a couple of days. If it doesn’t, seek medical advice.

It is important to keep hydrated, particularly if it is a child or baby that is ill, and you can also try:

  • Applying a cool damp cloth to the forehead
  • Ensuring you are not wearing too many layers, causing you to overheat
  • Using a fan to keep cool
  • Taking Paracetamol or Ibuprofen

If your child has a temperature, make sure they are not wearing too many layers but also be careful that they do not become cold.

How can Push Doctor help?

At Push Doctor, you can see a GP online, on any device, from home, work or even on the go. Our doctors can discuss your symptoms during a video consultation, listen to your concerns and suggest the right treatment to get you back up on your feet as quickly as possible.

They can also consult with your child. Find out more about that here.

You can see a GP about your fever at a time that suits you 7 days a week and can offer you the advice, diagnosis and treatment you may need. Book an appointment now.