Fever is a temporary rise in body temperature that usually occurs when the immune system responds to an infection, inflammation, or another medical condition. It is a common symptom rather than a disease itself and can a
Fever is a temporary rise in body temperature that usually occurs when the immune system responds to an infection, inflammation, or another medical condition. It is a common symptom rather than a disease itself and can affect people of all ages. Fever may develop suddenly or gradually and can last for a few hours, several days, or longer depending on the underlying cause.
A normal body temperature can vary throughout the day and from person to person. Fever is generally considered a body temperature of 38°C (100.4°F) or higher, although the exact measurement can depend on where and how the temperature is taken.
Fever is often the body's natural defense mechanism. An increased temperature can support the immune system in fighting certain infections. Common causes include viral infections, bacterial infections, flu, respiratory infections, urinary tract infections, and gastrointestinal infections. Fever can also occur with inflammatory conditions, certain medicines, heat-related illnesses, and other medical problems.
Depending on the cause, fever may occur with chills, sweating, headache, body aches, weakness, fatigue, loss of appetite, cough, sore throat, nausea, vomiting, or diarrhea. Children may become irritable or less active when they have a fever.
Most mild fevers caused by common infections improve as the underlying illness resolves. Adequate fluids, rest, and comfortable clothing can help. However, very high or persistent fever, particularly when accompanied by severe symptoms, may require medical evaluation.
Viruses are among the most common causes of fever. Colds, influenza, COVID-19, viral gastroenteritis, and other viral infections can produce an elevated body temperature.
Other symptoms may include cough, runny nose, sore throat, headache, fatigue, body aches, vomiting, or diarrhea.
Bacterial infections can also cause fever. Examples include urinary tract infections, bacterial pneumonia, throat infections, and some skin infections.
The symptoms depend on which part of the body is affected.
Infections involving the nose, throat, and lungs may cause fever along with cough, sore throat, congestion, mucus production, wheezing, or breathing difficulties.
A urinary tract infection can cause fever, particularly when the infection spreads toward the kidneys.
Other symptoms may include burning during urination, frequent urination, lower abdominal discomfort, or pain in the back or side.
Stomach and intestinal infections can cause fever along with diarrhea, vomiting, abdominal cramps, and nausea.
Food poisoning is another common cause of gastrointestinal symptoms with fever.
Some inflammatory or autoimmune conditions can cause recurring or prolonged fever.
In these situations, fever may occur with joint pain, fatigue, skin changes, or other systemic symptoms.
Exposure to very high temperatures can cause the body's temperature to rise.
Heat exhaustion can cause sweating, weakness, dizziness, headache, and nausea. Extremely high body temperature with confusion or loss of consciousness may indicate heatstroke, which is a medical emergency.
Some medicines can cause fever as a side effect. A temporary fever may also occur after certain vaccinations as the immune system responds.
Persistent or unusually high fever should be discussed with a healthcare professional.
Influenza commonly causes fever, chills, cough, sore throat, body aches, headache, and significant fatigue.
Symptoms can develop suddenly and may be more severe than those of an ordinary cold.
Pneumonia is an infection of the lungs that may cause fever, cough, chest discomfort, shortness of breath, chills, and fatigue.
Older adults and people with certain chronic conditions may have less typical symptoms.
Malaria is a serious infection transmitted by infected mosquitoes in areas where the disease is present.
It can cause fever, chills, sweating, headache, weakness, and body aches. Suspected malaria requires prompt medical testing and treatment.
Typhoid fever is a bacterial infection that can cause prolonged fever, weakness, headache, abdominal discomfort, diarrhea or constipation, and loss of appetite.
It requires appropriate medical diagnosis and antibiotic treatment when confirmed.
A UTI can cause fever, particularly when the kidneys are involved.
Fever accompanied by back or side pain, vomiting, or significant weakness requires prompt medical evaluation.
Meningitis involves inflammation of the membranes surrounding the brain and spinal cord.
Fever may occur with severe headache, neck stiffness, vomiting, confusion, sensitivity to light, or changes in consciousness. These symptoms require emergency medical attention.
Fever may occur with:
The combination of symptoms can provide important clues about the underlying cause.
A person should consult a healthcare professional if fever persists, repeatedly returns, becomes unusually high, or is associated with worsening symptoms.
Medical assessment is particularly important when fever occurs with difficulty breathing, persistent vomiting, severe abdominal pain, painful urination, severe headache, unexplained rash, or significant weakness.
People with weakened immune systems or serious chronic conditions may require medical evaluation sooner when they develop a fever.
Seek urgent medical attention if fever is accompanied by:
These symptoms may indicate a serious infection or another medical emergency.
Doctors usually evaluate fever by measuring body temperature and reviewing other symptoms.
They may ask about:
A physical examination may include checking the throat, ears, lungs, abdomen, skin, heart rate, blood pressure, and hydration status.
Blood tests may help identify infection, inflammation, anemia, or other abnormalities.
Urine testing may be performed when a urinary infection or kidney problem is suspected.
Chest X-rays, ultrasound, CT scans, or other imaging may be recommended depending on symptoms and suspected source of infection.
Stool tests, throat swabs, respiratory tests, malaria testing, or other investigations may be necessary depending on the patient's symptoms, location, and medical history.
Treatment depends on the cause of the fever.
For mild fever caused by a common infection, rest and adequate fluid intake are often important. Lightweight clothing and a comfortable room temperature can also help.
Fever-reducing medicines such as paracetamol or ibuprofen may be appropriate for some people, but they should be taken according to the product instructions and individual medical advice.
Antibiotics do not treat viral infections and should only be used when a bacterial infection is suspected or confirmed and a healthcare professional recommends them.
Treatment of malaria, typhoid fever, pneumonia, urinary infections, or other specific illnesses requires appropriate medical evaluation and targeted treatment.
For a mild fever without warning signs:
Drink plenty of fluids.
Get adequate rest.
Wear comfortable, lightweight clothing.
Keep the room comfortably cool.
Eat nutritious foods as tolerated.
Monitor body temperature when necessary.
Avoid excessive physical activity.
Follow medicine instructions carefully.
Very cold baths or aggressive cooling methods are generally unnecessary and may cause discomfort or shivering.
Fever is common in children and often occurs during viral infections.
Parents should monitor the child's temperature, fluid intake, urination, activity level, and other symptoms.
Medical attention should be sought if a child appears seriously ill, has difficulty breathing, experiences a seizure, develops a stiff neck, becomes difficult to wake, shows signs of dehydration, or develops a concerning rash.
Infants younger than 3 months with a temperature of 38°C (100.4°F) or higher require prompt medical assessment.
Fever during pregnancy can occur because of infections and other conditions. Because some infections may affect both the pregnant person and the developing baby, persistent or significant fever should be discussed with a healthcare professional.
Pregnant people should consult a healthcare professional before taking medicines to reduce fever.
Fever accompanied by severe headache, breathing difficulty, abdominal pain, urinary symptoms, or other concerning signs requires prompt medical evaluation.
Some causes of fever can be reduced through healthy habits and infection prevention.
Helpful measures include:
Wash hands regularly.
Avoid close contact with people who are sick when possible.
Practice safe food preparation.
Drink safe and clean water.
Keep recommended vaccinations up to date.
Avoid mosquito bites in areas where mosquito-borne diseases are common.
Maintain good personal hygiene.
Avoid sharing personal items during infections.
Travelers should follow appropriate health precautions based on their destination.
Most mild fevers do not cause serious complications. However, prolonged fever can contribute to:
Very high temperatures, particularly those caused by heatstroke, can damage organs and become life-threatening.
In children, fever associated with certain infections may occasionally be accompanied by febrile seizures. Most febrile seizures are brief, but any first seizure requires medical assessment.
Fever is a temporary increase in body temperature that commonly occurs when the immune system responds to an infection or inflammation. It is a symptom rather than a disease and can affect people of all ages.
Common causes include viral infections, bacterial infections, influenza, respiratory infections, urinary tract infections, gastrointestinal infections, inflammatory conditions, and heat-related illness. Diseases such as malaria, typhoid fever, pneumonia, and meningitis can also cause fever.
Diagnosis depends on the temperature, duration of symptoms, medical history, and other accompanying symptoms. Blood tests, urine tests, imaging, or specific infection tests may be required when the cause is unclear.
For mild fever, adequate hydration, rest, comfortable clothing, and appropriate monitoring can often provide supportive care. Fever-reducing medicines may be used when appropriate and according to medical advice.
See a healthcare professional if fever persists, repeatedly returns, becomes unusually high, or occurs with significant weakness, persistent vomiting, severe abdominal pain, breathing difficulty, or other concerning symptoms.
Seek emergency medical care for fever accompanied by confusion, seizures, fainting, severe breathing difficulty, severe headache with neck stiffness, severe dehydration, or other signs of serious illness.
Finding the underlying cause of persistent or severe fever is important because appropriate treatment depends on whether the fever is caused by an infection, inflammation, medication, heat exposure, or another medical condition.
Seek immediate medical attention if fever is severe, sudden, or accompanied by chest pain, difficulty breathing, sudden weakness, loss of consciousness, or severe bleeding.
Medical Disclaimer: This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider. In an emergency, call emergency services immediately.