The signs and symptoms of fever

Woman and baby with a fever

A fever is a temporary rise in body temperature due to infection or any other secondary cause. It is a sign that something is happening within the body that needs to be examined.1

Usually adults with a fever may feel uncomfortable and it is not a cause for concern unless their body temperature reaches 39.4°C or higher.1

For infants and children, a temperature of 38.0°C or higher when taken rectally, is indicative of a fever.1,2

Symptoms of fever

Symptoms of fever in adults

Symptoms of fever in adults include sweating, chills and shivering, headache, muscle aches, loss of appetite, irritability, dehydration, and a sense of general weakness.1

Symptoms of fever in children

Other than a raised temperature of more than 38.0°C, children may exhibit symptoms of fever differently from adults.1,2

Febrile children may not be as active or talkative as usual or may seem fussier, less hungry but thirstier. On touching the child, they may feel hot or warm.2

Mother checking child’s temperature

Recognizing “red flag” symptoms

Adults with fever must be referred to a doctor if there is accompanying:1

  • Severe headache
  • Unusual skin rash
  • Unusual sensitivity to bright light
  • Stiff neck or pain when they bend their head forward
  • Mental confusion
  • Persistent vomiting
  • Difficulty in breathing or chest pain
  • Abdominal pain or pain when urinating
  • Convulsions or seizures

Children with fever must be referred to a doctor when:3

  • Their skin looks very pale or grey, or is cool, or mottled
  • They seem confused, cry constantly, and cannot be settled
  • They are very weak and have difficulty waking up
  • They have trouble breathing
  • If they are less than 3 months old, with a fever of ≥38.0°C
  • They have a stiff neck
  • They experience a seizure, or a long seizure associated with fever
  • They develop a rash with small purple dots

Understanding fever

Child with fever

Fever overview

Find out the basics about fever.


Fever/temperature icon

What causes fever?

Learn more about the causes of fever.



What can you recommend to your patients for fever?

Find out more about non-pharmacological and pharmacological treatments for fever in both children and adults.


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Advil product images

Acute pain and/or fever relief products for adults

Help your adult patients manage their acute pain and fever with the full range of effective and well-studied pain-relieving Advil products.4,5

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Children’s Advil — helping parents relieve children’s fever and pain

With proven efficacy in different types of pain and a well-established safety profile — you can trust the pain relief of ibuprofen in Advil.5,6

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Musculoskeletal pain

Learn more about acute strains and sprains and how they can be relieved.

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