


Dr Sarah Jarvis MBE







How do you know if you have a fever without a thermometer?

Using a thermometer is the best way to tell if you have a fever. However, if you don't have one, the following will give you a rough idea:

  • Feel your forehead with the back of your hand. This is much more sensitive to temperature than the palm.
  • Look in the mirror. If you have a fever, your cheeks may be flushed.
  • Check for general symptoms of infection, such as aches and pains, tiredness or muscle weakness.
  • Check your wee - if it's darker than usual you may be getting dehydrated from excess sweating.
  • Ask anyone around if they feel hot - obvious, really but if they do, it could just mean you need to turn down the heating.


Dr Sarah Jarvis MBE



Paracetamol or ibuprofen may help to reduce the fever. 


Dr Sarah Jarvis MBE

In children, paracetamol and ibuprofen are usually only recommended if the child is distressed with the fever. Remember that just because a fever responds to medicine, this does not mean that you should stop looking out for signs of serious illness (such as a non-blanching rash).

Note: in children, giving paracetamol or ibuprofen does not reduce the risk of a seizure caused by a fever occurring. See the separate leaflet called Febrile Seizure (Febrile Convulsion).


You should contact a doctor if you or your child have a high temperature (fever) and:

  • Your child has a fit.
  • You or your child develop a rash that does not disappear when you press a glass on it (a non-blanching rash).
  • You or your child are becoming more unwell.
  • The fever lasts longer than five days.




Fever caused by infections

Common conditions that can cause fevers include:

If you have been abroad and develop a fever, it is important to see a doctor. Infections sometimes caught abroad can also cause a fever. See the separate leaflets called Malaria, Tuberculosis, Hepatitis A, Hepatitis B and Lyme Disease.

Your child's temperature can also be raised when their teeth start to develop (their teething period), following some vaccinations, or if they overheat because of too much bedding or clothing. See the separate leaflets called Teething, Immunisation and Sudden Infant Death (Cot Death).

Fever caused by other conditions

Less commonly, fever can be caused by conditions other than infections. For example, blood clots in the leg or lung can sometimes lead to a fever developing. See the separate leaflets called Deep Vein Thrombosis and Pulmonary Embolism.

There are some conditions which cause swelling (inflammation) in the body. If you have one of these conditions, a common symptom you may experience is fever. See the separate leaflets called Rheumatoid Arthritis and Systemic Lupus Erythematosus.

There are also some types of cancer which can lead to a fever developing. See the separate leaflet called Cancer.


Flu vaccination.
Protect yourself this autumn.
Check eligibility

Further reading and references

Why do women feel the cold more than men?
Health Tools

Feeling unwell?

Assess your symptoms online with our free symptom checker.

Start symptom checker