What is a fever?
A fever is a temporary rise in body temperature, often due to an illness. It is the body’s natural way of fighting infection. A normal body temperature is around 98.6 degrees Fahrenheit or 37 degrees Celsius, but a fever is typically defined as a temperature of 100.4 degrees Fahrenheit or higher.
Fever itself is not a disease but a sign that something may be going on in the body, such as an infection or inflammation.
What causes a fever?
Fever can be caused by many different things. Common causes include:
- Viral infections like the flu or common cold
- Bacterial infections such as strep throat or urinary tract infections
- Heat exhaustion
- Inflammatory conditions like rheumatoid arthritis
- Certain medications or vaccinations
- In rare cases, more serious illnesses such as cancer or autoimmune disorders
What are the symptoms of a fever?
In addition to a raised body temperature, other signs and symptoms that may accompany a fever include:
- Chills and shivering
- Sweating
- Headache
- Muscle aches
- Loss of appetite
- Fatigue or weakness
- Dehydration
- Irritability (especially in children)
In very high fevers, especially in young children, you might also notice confusion, difficulty breathing, or even seizures.
How is a fever measured?
A fever can be measured using a thermometer. There are several types:
- Oral thermometers (under the tongue)
- Rectal thermometers (especially for infants)
- Ear (tympanic) thermometers
- Forehead (temporal) scanners
Rectal temperatures tend to be more accurate for babies, while oral or forehead thermometers are commonly used for older children and adults.
When should I be concerned about a fever?
Most fevers are mild and go away on their own. However, you should contact a healthcare provider if:
- A baby under 3 months old has a temperature of 100.4°F or higher
- A child between 3 and 6 months has a fever over 102°F
- A fever lasts longer than 3 days
- You or your child has a fever along with a stiff neck, severe headache, confusion, rash, chest pain, or difficulty breathing
- A seizure occurs due to the fever
- The person has a weakened immune system or chronic illness
How is a fever treated?
Fever often does not need treatment unless it is very high or uncomfortable. When treatment is needed, options include:
Over-the-counter medications:
- Acetaminophen or ibuprofen can reduce fever and discomfort. Always use the correct dose based on age and weight.
- Avoid giving aspirin to children due to the risk of Reye’s syndrome.
Home care:
- Stay hydrated with water, clear fluids, or electrolyte drinks
- Get plenty of rest
- Use light clothing and keep the room cool
- Take lukewarm baths or use damp washcloths to help lower the temperature
Can a fever be dangerous?
Most fevers are not harmful and actually help the body fight off infections. However, extremely high fevers, especially those over 104°F, can be serious if left untreated, particularly in young children and people with certain medical conditions.
Febrile seizures can happen in children between 6 months and 5 years of age, but they usually do not cause long-term harm.
How can fever be prevented?
While you can’t always prevent fever, you can lower the risk by taking steps to avoid infections:
- Wash hands frequently
- Avoid close contact with people who are sick
- Stay up-to-date on vaccinations
- Practice good hygiene and sanitation
- Eat a healthy diet and get regular exercise to support the immune system