Fever is a rise in body temperature, usually above 38°C (100.4°F). It is a sign that the body is responding to something — most often an infection.
See a doctor if
- Fever above 40°C (104°F)
- Fever lasting more than three days
- Fever with severe headache, neck stiffness, rash or confusion
- Fever with breathlessness or chest pain
- Fever in a baby under three months, at any level
- Fever with any dengue warning sign, such as severe stomach pain, repeated vomiting or bleeding
Common causes
These are causes doctors commonly see. This list cannot tell you which one applies to you.
- Viral infections including flu and dengue
- Bacterial infections such as throat, urine or chest infections
- Malaria and typhoid in areas where they occur
- Tuberculosis, typically with evening fever and night sweats
- Reaction after a vaccination, usually brief
Frequently Asked Questions
When should I worry about a fever?
Get medical help for a fever above 40°C (104°F), a fever lasting more than three days, or a fever with severe headache, neck stiffness, rash, confusion, breathlessness or chest pain. Any fever at all in a baby under three months needs to be seen the same day.
Does every fever need an antibiotic?
No. Most fevers are caused by viruses, and an antibiotic does nothing to a virus except add side effects and contribute to resistance. Whether one is needed is a decision for a doctor who can examine you.
What causes fever in India during the monsoon?
Dengue, malaria, typhoid and chikungunya all rise in and after the monsoon, alongside ordinary viral fevers. They can look similar in the first few days, which is why a fever that persists beyond about three days should be tested rather than treated by guesswork.
What to do next
Note when the symptom started, how it has changed, and anything that makes it better or worse. Take that information — and a list of your medicines — to your doctor. It makes the consultation considerably more useful than trying to recall it on the spot.
If any of the warning signs above apply to you, do not wait for an appointment. Go to a hospital, or call 112.