Fever - Symptoms & Causes

What is a fever?

A fever is an increased body temperature of 37.4°C or above. It is the body's natural response when fighting an infection.

In children, it is common to see high temperatures of up to 40°C. Having a higher temperature does not indicate a more severe illness. However, for infants and toddlers, a fever may suggest a serious infection.

What are the symptoms of a fever?

When you have a fever, your body temperature is higher than 37.4°C. Don’t rely on touch to assess a temperature. Use a thermometer.

As a child, you may also experience:

  • Irritability
  • Lethargy
  • Longer sleeping time
  • Febrile fits during a sudden rise in temperature, or before a fever is detected.
  • Reduced appetite for food and drinks
  • Shivers

As an adult, you may also experience:

  • Headaches
  • Body aches
  • Hot, flushed face
  • Loss of appetite
  • Sweating or weakness
  • Shivers

When to visit the UCC?

Visit our 24-Hour Urgent Care Centre (UCC)​ if you or your child have the following symptoms or medical history:


Your young infant (below 3 months old) has a temperature of 38°C or more, or your child displays the following symptoms:

  • A temperature exceeding 41°C
  • Drowsiness or increased lethargy
  • Fever for a few days with no other symptoms
  • Extremely irritability or inconsolability despite efforts to lower the fever
  • Recurrent vomiting, with a stiff neck or severe headache
  • Refusal to drink fluids or unable to pass enough urine
  • Severe pain over any part of the body
  • Red lips, red eyes or a rash
  • Hard or fast breathing
  • Febrile fit or seizures
  • Smelly urine


You had:

  • A seizure or fits, coupled with fever
  • Surgery or a medical procedure recently

You are:

  • Pregnant
  • Coughing up blood
  • Struggling to breathe
  • Undergoing chemotherapy with an oral temperature that exceeds 38ºC for more than 1 hour
  • Taking steroids and medicines used to prevent rejection after an organ transplant

You have:

  • Rashes
  • Infections often
  • Diabetes, heart disease, cancer, lupus, or sickle cell anaemia
  • Recently been to Africa, Asia, Latin America, or the Middle East
  • Severe pain in the belly, back, or sides
  • Severe headache or neck pain
  • Severe vomiting or diarrhoea
  • Seizure or confusion
  • Severe chest pain

What causes fever?

In children, fever is usually caused by the following.

A fever might be also be caused by:

  • Heat exhaustion
  • Certain inflammatory conditions
  • Certain drugs and medications
  • Malignant tumours
  • Vaccinations
This page has been reviewed by our medical content reviewers.

Need help?

For enquiries, please call
+65 6250 0000 (Orchard) or +65 6898 6898 (Novena)

For appointment bookings, please WhatsApp
+65 8111 7777 (Orchard) or +65 8111 5777 (Novena)