Common early signs of a fever
Depending on the cause of the fever, additional signs and symptoms may include:
- Sweating
- Chills and shivering.
- Headache
- Muscle pains
- Loss of appetite
- Irritability
- Dehydration
- General weakness
What exactly is a fever?
A fever is a temporary increase in body temperature that is part of the body’s immune response. An infection commonly causes it. Body temperatures differ slightly among individuals and can fluctuate during the day. The widely accepted average temperature is 98.6°F (37 °C). Typically, a reading of 100°F (37.8 °C) or higher with an oral thermometer is considered a fever.
For most children and adults, a fever can be uncomfortable, but it typically does not cause concern. However, in infants, even a mild fever might signal a severe infection.
Fevers typically resolve within a few days. Several over-the-counter medications can reduce a fever. However, you do not always need to treat a fever if it is not causing discomfort.
What are the causes of fever?
Normal body temperature results from a balance between heat production and heat loss. The hypothalamus, often called your body’s “thermostat,” monitors this equilibrium. Even when healthy, body temperature fluctuates slightly during the day, typically being lower in the morning and higher in the late afternoon and evening.
When your immune system fights disease, the hypothalamus may increase your body temperature. This activates complex mechanisms that produce additional heat and reduce heat loss. Shivering is one way the body generates heat. Covering up with a blanket when you feel cold helps your body conserve heat.
Fever temperatures below 104°F (40°C), often linked to common viral infections like the flu, can support the immune system in fighting disease and are typically not dangerous. Elevated body temperature can be caused by:
- A viral infection
- A bacterial infection
- Heat exhaustion
- Certain inflammatory conditions, such as rheumatoid arthritis, involve inflammation of the joint lining (the synovium).
- A malignant tumor
- Some medications, such as antibiotics and drugs used to treat high blood pressure or seizures
- Some immunizations, including the diphtheria, tetanus, and acellular pertussis (DTaP) vaccine, pneumococcal vaccine, or COVID vaccine.
How is fever diagnosed?
To assess a fever, your doctor might:
- Inquire about your symptoms and medical background.
- Conduct a physical examination.
- Collect samples from the nasal passage or throat to test for respiratory infections.
- Order tests, such as blood tests or a chest X-ray, as needed, based on your medical history and physical exam.
Since a fever can signal a serious illness in a young infant, particularly those two months old or younger, your baby may be hospitalized for testing and treatment.
How is the fever managed or addressed?
For a mild, low-grade fever, your care provider might not recommend medications to lower your body temperature. Such minor fevers can actually help reduce the number of microbes responsible for your illness. However, a fever exceeding 102°F (38.9°C) can cause discomfort and generally needs treatment.
- Over-the-counter medications: If you experience a high fever or one that’s uncomfortable, your care provider might suggest nonprescription options like acetaminophen (Tylenol, others) or ibuprofen (Advil, Motrin IB, others).
- Prescription medications: Your doctor may prescribe additional drugs depending on the cause of your illness. Addressing the root cause can help reduce symptoms, including fever.
Treatment of infants
Infants, particularly those under 2 months old, may require hospital admission for testing and treatment. For babies this age, a fever can signal a severe infection that needs IV medications and continuous monitoring.
How can fever be prevented?
You might prevent fevers by minimizing your contact with infectious diseases. Here are some helpful tips:
- Get vaccinated according to recommendations for infectious diseases such as influenza and COVID-19.
- Adhere to public health guidelines by wearing masks and practicing social distancing.
- Wash your hands frequently and instruct your children to do the same, particularly before eating, after using the toilet, after being in crowded places or around sick individuals, after handling animals, and while using public transportation during travel.
- Teach your children to wash their hands properly by applying soap to both the front and back of each hand, then rinsing thoroughly under running water.
- Bring hand sanitizer with you for situations without soap and water.
- Avoid touching your nose, mouth, or eyes, as these are primary entry points for viruses and bacteria that can cause infection.
- Cover your mouth when coughing and your nose when sneezing, and teach your children to do the same. Whenever possible, turn away from others and cough or sneeze into your elbow to help prevent the spread of germs.
- Refrain from sharing cups, water bottles, and utensils with your child(ren).
Check Fever Signs
Living with the fever
A fever commonly indicates an infection. It usually is not a cause for concern by itself, but the underlying illness may require medical treatment. In many cases, a fever will go away on its own without needing medical help. However, if a child or an older adult has a fever, severe or worsening symptoms, or a weakened immune system, they should see a healthcare professional. Your appointment might be with your family doctor, paediatrician, or another healthcare provider. Here is some information to help you prepare and understand what to expect. Check for any pre-appointment instructions. When scheduling, ask if there is anything you need to do beforehand. Record details about the fever, such as when it began, how and where it was measured (for example, orally or rectally), and other symptoms. Note whether you or your child has been near anyone who is sick. Write down key personal information, including possible exposure to illness or recent travel. Make a list of all medications, vitamins, and supplements you or your child is taking. Prepare questions to ask your doctor.
Frequently Asked Questions
What is the typical duration of a fever?
The duration of the fever depends on its cause. Usually, if an infection is the cause, the fever should resolve within 3 to 4 days. Contact your healthcare provider if the fever persists beyond this time or if breathing changes.
How can I take care of myself when I have a fever?
To help yourself or your child feel more comfortable during a fever, try these steps: Drink plenty of fluids, such as water and clear broth, which aid heat loss and help replace fluids lost through sweating. Infants under 6 months should only consume breast milk or formula. Rest is crucial for recovery because activity can increase body temperature. Stay cool by wearing light clothing, keeping the room at a comfortable temperature, and sleeping with only a sheet or a light blanket if you’re not shivering.
When is the right time to contact my doctor about my infant?
Contact your doctor immediately if a baby under 3 months develops a fever. Seek urgent medical care if the fever is accompanied by seizures, drowsiness, irregular breathing, stiff neck, confusion, purple-spotted rash, ear tugging, persistent sore throat, vomiting, diarrhoea, or painful, burning, or frequent urination.
What exactly is a fever dream?
Fever dreams are vivid, strange, or unpleasant dreams that occur when your body temperature exceeds normal levels. The precise cause of fever dreams remains unknown. However, some researchers believe that fevers cause the brain to “overheat,” impairing cognitive function and leading to more unusual dreams. Additionally, fevers might disrupt your REM sleep cycle, leading to atypical dreams.
What exactly is a recurrent fever?
Recurrent fever occurs multiple times over a period. Providers refer to these as episodic because they appear and disappear. The fever typically lasts a few days before subsiding for some time. During these intervals, your child generally remains healthy and usually acts. Recurrent fevers are most common in children under five and are a key symptom of periodic fever syndromes, a group of related conditions.
