Causes of fever

Woman and baby with a fever

How does fever occur?

Fever occurs when the hypothalamus resets the normal temperature point to a higher level. Though the body is still working to balance the heat produced with that which it releases, since the set-point is now higher, the body temperature rises.1

The increase in body temperature occurs due to various reasons such as release of certain chemicals called cytokines in response to invading microorganisms, cancer cells or any other foreign matter. It is also in response to the body producing white blood cells and antibodies to protect it from the invading foreign matter.2

Common causes of fever

Child with fever

Infectious causes of fever3,4

Any form of infection can cause the body to respond with a fever. These include viral and bacterial infections. Some examples are:

Viral infections

Common cold




Bacterial infections


Bacterial pneumonia


Skin infections

Urinary tract infections

Otitis media (ear infections)

Eye infections

  • Woman with a fever

    Though it is more common for a person to develop fever because of an infection, there are non-infectious causes of fever. These include:

    Auto-immune diseases

    Systemic lupus erythematosus (SLE)

    Rheumatoid arthritis




    Drug induced

    Sulfa drugs

    Some anti-epileptic medications

    Antiretroviral medicines (for treatment of HIV)

    Some antiarrhythmic medications (e.g. amiadarone)

    Crystal-induced arthropaties Gout (accumulation of uric acid in the joints)
    Thromboembolism Deep vein thrombosis
    Abdominal conditions Acute pancreatitis
    Central nervous system conditions Stroke (haemorrhagic and ischaemic)
  • Baby smiling

    Some of the more common causes of fever in children are:

    Upper respiratory tract infections
    Ear infections
    Roseola which is caused by a virus and associated with a rash
    Common childhood illnesses e.g. chicken pox
    After immunisations

    However, contrary to popular believe, teething does not cause fever. There may be a slight increase in temperature during teething due to the irritation of the gums, but it is not high enough to qualify as a fever.7 This is important to remember as, if the child who is teething has a fever, then there may be an underlying infection that should be treated.

Understanding fever

Signs and symptoms

Fever overview

Find out the basics about fever.


Signs and symptoms

How do they present?

Refresh your knowledge on the signs and symptoms of fever and learn about “red flag” symptoms that indicate a referral to the doctor.

Signs and symptoms


What can you recommend to your patients for fever?

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


Learn more

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Patient care resources

Patient care resources

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