Get medical help immediately if any of these apply
- Fever with a stiff neck, severe headache, or a rash that does not fade when pressed.
- Fever with difficulty breathing, chest pain, or rapid breathing.
- Fever with confusion, unusual drowsiness, or difficulty waking.
- Fever with a seizure.
- Any fever in an infant under three months old.
- A child who is floppy, unusually drowsy, refusing fluids, or has no wet nappies.
- Fever with severe abdominal pain, or vomiting that prevents keeping fluids down.
- Fever in someone on chemotherapy, immunosuppressants, or with a known immune condition.
- Fever that persists beyond about five days, or returns after settling.
This list is not exhaustive. Anything sudden, severe, or rapidly worsening needs immediate medical attention regardless of what any website says. In India, call 112 for any emergency or 108 for an ambulance. Elsewhere, use your local emergency number.
What a fever is
A fever is a raised body temperature, generally taken as 38°C (100.4°F) or above. It is part of the immune response — most often to a viral or bacterial infection, but sometimes to inflammation, medication, or other causes.
The height of a fever is a weaker guide than people expect. A high temperature in an otherwise alert person is often less concerning than a modest one in someone who is drowsy, breathless, or not drinking. How the person looks and behaves matters more than the number.
Common causes
- Viral infections — the most frequent cause by a wide margin, including colds, flu, and gastrointestinal infections.
- Bacterial infections — throat, ear, chest, urinary tract, or skin.
- Mosquito-borne illness — in India, dengue, malaria, and chikungunya are important considerations, especially seasonally or after travel.
- Typhoid and other food- or water-borne infections.
- Post-vaccination fever — usually mild and short-lived.
- Non-infectious causes — inflammatory conditions and some medicines.
What to tell a doctor
- How many days the fever has lasted, and whether it comes and goes.
- The highest reading you have measured and how you measured it.
- Everything accompanying it — rash, cough, urinary symptoms, diarrhoea, joint pain, headache.
- Recent travel, mosquito exposure, or contact with anyone unwell.
- Any medicines taken, including anything already used to bring the fever down.
- Existing conditions, pregnancy, and immune status.
Staying safe while it runs its course
For a fever without red flags, the general principles are rest, steady fluids, and monitoring. Do not start or change any prescription medicine on your own, and do not use leftover antibiotics — most fevers are viral, where antibiotics do nothing and cause harm.
Which doctor treats this
Picking the wrong speciality for a first consultation costs time and money. These are the specialities that commonly handle this, though your particular situation may point elsewhere — work out which specialist to see.
- General physician or family doctor — the right first stop for most fevers.
- Paediatrician — for any child, and urgently for infants.
- Infectious disease specialist — for prolonged, recurring, or unexplained fever.
- Emergency department — for any red flag above.
Questions worth asking your doctor
- Do my symptoms suggest a viral or bacterial cause, and how would we tell?
- Do I need blood tests, and which ones — particularly for dengue, malaria, or typhoid?
- What temperature or symptom should bring me back immediately?
- How long is it reasonable for this fever to last before it needs review?
- Are any of my regular medicines affected while I have a fever?
How DoctoGuide can help
This page is general information — it cannot know your age, history, medicines, or how your symptoms actually present. DoctoGuide asks those follow-up questions, then gives you guidance specific to what you described, a sense of urgency, the speciality to see, and a written summary to take into the consultation. It is free and needs no account.
DoctoGuide does not diagnose, prescribe, or replace a doctor. What it can and cannot do is set out on the medical safety page.