Fever is a common medical condition that occurs when your body temperature rises above normal. It is usually a sign that the body is fighting an infection or illness.
Fever is not a disease itself but a symptom of an underlying problem. Understanding the causes, symptoms, and treatments of fever can help manage it safely and know when to seek medical care.
What Is Fever?
Normal body temperature is around 98.6°F (37°C), but it can vary slightly between individuals. Fever is usually defined as:
- Mild fever: 100–101°F (37.8–38.3°C)
- Moderate fever: 101–102.5°F (38.3–39.2°C)
- High fever: 102.5–104°F (39.2–40°C)
- Very high fever: Above 104°F (40°C) — medical emergency
Fever is the body’s natural defense mechanism. When the body detects bacteria, viruses, or other harmful substances, it raises temperature to help fight the infection.
Causes of Fever
Fever can occur due to many reasons, including:
1. Infections
- Viral infections: Common cold, flu, COVID-19, dengue, chikungunya
- Bacterial infections: Pneumonia, urinary tract infection, strep throat
- Parasitic infections: Malaria, amoebiasis
2. Inflammatory Conditions
- Rheumatoid arthritis
- Inflammatory bowel disease
3. Heat-Related Illness
- Heat exhaustion or heatstroke
4. Medication-Induced Fever
- Some medicines can cause fever as a side effect (drug fever)
5. Immunizations
- Mild fever may occur after vaccines as the body builds immunity
6. Other Causes
- Cancer (rare)
- Autoimmune diseases
- Hormonal imbalances
Symptoms of Fever
The main symptom is increased body temperature, but fever can cause other signs:
- Sweating
- Chills and shivering
- Headache
- Muscle aches
- Weakness or fatigue
- Loss of appetite
- Dehydration (dry mouth, thirst, less urination)
- Irritability (especially in children)
How to Measure Fever
Fever can be measured using:
- Digital thermometer: Under the tongue (oral) or armpit (axillary)
- Ear thermometer (tympanic): Fast and convenient
- Forehead thermometer (temporal artery): Non-contact method
Normal temperature ranges:
- Oral: 97.6–99.6°F (36.5–37.5°C)
- Axillary: 96.6–98.6°F (35.9–37°C)
- Rectal: 98.6–100.6°F (37–38.1°C)
A reading above these ranges indicates fever.
When Fever Is Serious
Most fevers are mild and resolve on their own. Seek medical care if:
- Fever lasts more than 3 days
- Temperature rises above 104°F (40°C)
- Severe headache, stiff neck, or confusion occurs
- Seizures or unconsciousness
- Difficulty breathing or chest pain
- Persistent vomiting or diarrhea
- Signs of dehydration (dry mouth, little urine)
Children, infants, elderly people, and people with chronic illnesses may need immediate medical attention even for moderate fever.
Diagnosis of Fever
Doctors may perform tests to find the underlying cause of fever:
- Physical examination – checking the throat, ears, chest, and abdomen
- Blood tests – CBC, blood culture, inflammatory markers
- Urine tests – to detect urinary tract infections
- X-rays or imaging – if pneumonia or internal infection is suspected
- Other specific tests – malaria test, dengue test, COVID-19 test, etc.
Treatment of Fever
Fever treatment depends on the cause. In most cases, it is self-limiting and does not need strong medications.
1. Home Care for Mild Fever
- Rest and sleep adequately
- Drink plenty of water and fluids to prevent dehydration
- Wear light clothes and keep the room cool
- Use lukewarm sponge baths to reduce high temperature
2. Medications
Common fever-reducing medicines include:
- Paracetamol (Acetaminophen): 500–1000 mg every 4–6 hours (do not exceed 4 g/day for adults)
- Ibuprofen: 200–400 mg every 6–8 hours (check with doctor if you have stomach or kidney problems)
3. Treating the Underlying Cause
- Antibiotics for bacterial infections (only with doctor’s prescription)
- Antivirals for certain viral infections (if prescribed)
- Antimalarials for malaria
Preventing Fever
While fever itself cannot always be prevented, you can lower the risk by:
- Practicing good hygiene – washing hands regularly
- Drinking clean water and maintaining sanitation
- Using mosquito nets in areas with malaria or dengue
- Getting vaccinated against common infections
- Avoiding contact with sick people
- Eating a balanced diet to strengthen immunity
Fever in Special Populations
1. Infants and Children
- Fever is common in children and often caused by infections.
- Seek immediate care if infants below 3 months have a fever above 100.4°F (38°C).
2. Elderly People
- Fever may be less obvious in older adults but can signal serious infections.
- Prompt medical attention is advised.
3. Pregnant Women
- Fever can harm the baby, especially in the first trimester.
- Contact a doctor if fever occurs during pregnancy.
Common Myths About Fever
- Fever is always dangerous – False. Mild fever is the body’s natural defense.
- Cold water or ice should always be applied – False. Lukewarm baths are safer.
- Antibiotics reduce all fevers – False. Antibiotics only work for bacterial infections, not viral.
When to See a Doctor
- Fever lasting more than 3 days
- Very high fever above 104°F (40°C)
- Severe symptoms such as chest pain, shortness of breath, or confusion
- Fever in infants, elderly, or pregnant women
- Fever with rash, bleeding, or seizures
Conclusion
Fever is a common symptom that signals your body is fighting an infection or other illness. Most fevers are mild and can be managed at home with rest, fluids, and fever-reducing medicine.
However, persistent or very high fever can indicate a serious underlying problem and requires medical attention. Understanding the causes, symptoms, and proper care of fever helps you stay safe and recover quickly.
FAQs
Q1. Can fever go away on its own?
Yes, most fevers caused by viral infections resolve in 2–3 days without treatment.
Q2. Can I take paracetamol for fever?
Yes, paracetamol is safe and effective when taken as recommended.
Q3. Is a fever always a sign of infection?
No, fever can also be caused by inflammation, heat, medications, or autoimmune conditions.
Q4. Can dehydration cause fever?
Yes, severe dehydration may increase body temperature.
Q5. Should I use antibiotics for fever?
Only if a bacterial infection is diagnosed by a doctor. Antibiotics do not work for viral fever.