A fever is characterized by an elevation in body temperature, often indicating the body’s response to an infection. While fevers are a common symptom and frequently harmless, playing a role in combating infections, it’s important to understand when a fever requires medical attention. For many fevers, treatment isn’t always necessary.
The average normal body temperature is typically around 98.6 degrees Fahrenheit (37 degrees Celsius). However, normal body temperature can fluctuate, generally ranging between 97°F (36.1°C) and 99°F (37.2°C) or even higher. Factors such as physical activity, age, and time of day can influence body temperature. Notably, older adults often exhibit lower baseline body temperatures compared to younger individuals.
When using a thermometer, the following readings are generally considered to indicate a fever:
- Rectal, ear, or temporal artery: 100.4°F (38°C) or higher
- Oral: 100.4°F (38°C) or higher
- Armpit (axillary): 99°F (37.2°C) or higher
When to Seek Emergency Care
Prompt medical attention is crucial for infants under 3 months old who develop a fever.
Emergency medical care is also necessary for a child exhibiting any of the following symptoms, particularly after being in a hot car, as these could signal heat-related illness:
- Fever with absence of sweating or excessive sweating
- Severe headache
- Seizures
- Stiff neck
- Confusion
- Repeated vomiting or diarrhea
- Irritability
- Any symptom that raises concern
Treatment
The primary aim of fever treatment is to enhance comfort and facilitate rest for both adults and children.
Infant and Child
Children with fevers may not always appear or behave as though they are sick. Whether to treat a fever depends largely on the child’s level of discomfort. If a child is noticeably uncomfortable or restless, the following home care strategies can be beneficial:
- Ensure adequate fluid intake.
- Dress the child in light, breathable clothing.
- Use a light blanket if the child experiences chills, and continue until the chills subside.
- For children 6 months and older, acetaminophen (Tylenol, others) or ibuprofen (Advil, Motrin, others) can be administered. Always carefully review and adhere to the dosage instructions on the product label. If the child has pre-existing health conditions or is taking other medications, consult a healthcare professional before using fever-reducing medicines.
Adult
Adults typically appear and feel ill when their fever reaches 103°F (39.4°C) or higher. To manage a fever in adults:
- Drink plenty of fluids to stay hydrated.
- Wear light clothing to avoid overheating.
- Use a light blanket if feeling chilled until the chills pass.
- Acetaminophen (Tylenol, others) or ibuprofen (Advil, Motrin IB, others) can be used to reduce fever and discomfort. Always follow the dosage instructions provided on the label. If you have existing health issues or are taking other medications, consult your healthcare provider before using fever medications.
What to Avoid
- Aspirin should not be given to children or teenagers due to the risk of Reye’s syndrome.
- Avoid giving any type of pain reliever to infants without first consulting a healthcare professional.
When to Call Your Doctor
Seek medical advice if a child of any age exhibits any of the following:
- Increased fussiness or unusual behavior that does not improve even after fever-reducing medication is given.
- Signs of dehydration, such as no wet diapers for 8 to 10 hours, absence of tears when crying, dry mouth, or refusal to drink fluids.
- Stiff neck or headache.
- Abdominal pain.
- Difficulty breathing.
- Rash.
- Joint pain or swelling.
- Fever lasting more than five days.
Consult a doctor for an adult with a fever who experiences any of these symptoms:
- Trouble breathing.
- Chest pain.
- Severe headache or stiff neck.
- Confusion.
- Abdominal pain.
- Repeated vomiting.
- Signs of dehydration, including dry mouth, reduced or dark urine output, or inability to drink fluids.
- Skin rashes.
- Difficulty swallowing liquids.
- Pain during urination or back pain.
| Fahrenheit-Celsius Conversion Table | |
|---|---|
| Fahrenheit | Celsius |
| 105 | 40.6 |
| 104 | 40.0 |
| 103 | 39.4 |
| 102 | 38.9 |
| 101 | 38.3 |
| 100 | 37.8 |
| 99 | 37.2 |
| 98 | 36.7 |
| 97 | 36.1 |
| 96 | 35.6 |
How to Take a Temperature
Always utilize a digital thermometer for accurate temperature measurement. Available types include:
- Rectal thermometers: Designed for rectal use, particularly in infants.
- Oral thermometers: For measuring temperature in the mouth.
- Temporal artery thermometers: Employ infrared technology to measure temperature via the temporal artery on the forehead.
- Armpit (axillary) and ear (tympanic membrane) thermometers: These are generally considered less accurate than rectal, oral, or temporal artery thermometers.
Avoid using mercury thermometers due to the hazards associated with mercury exposure.
Regardless of the thermometer type used, adhere to these guidelines:
- Carefully read and follow the manufacturer’s instructions provided with the thermometer.
- Clean the thermometer before and after each use with rubbing alcohol or soap and lukewarm water.
- Maintain separate thermometers for oral and rectal use to prevent cross-contamination. Clearly label each thermometer for its designated use.
- Never leave children unattended while taking their temperature.
Rectal Temperature (for Infants)
- Turn on the digital thermometer and apply a small amount of petroleum jelly or lubricant to the tip.
- Position the infant on their stomach or side with knees bent towards the chest.
- Gently insert the thermometer tip about 1/2 to 1 inch (1.3 to 2.5 centimeters) into the rectum.
- Hold the thermometer and the infant still until the thermometer beeps, indicating completion. Maintain a firm hold on the thermometer throughout the process to prevent injury.
- Remove the thermometer and note the temperature reading.
Oral Temperature
- Activate the digital thermometer. Place the thermometer tip under the tongue.
- Instruct the person to close their mouth firmly around the thermometer for the duration specified in the instructions or until a beep signals completion.
- Remove the thermometer and record the temperature.
Temporal Artery Temperature
- Turn on the temporal artery thermometer. Gently glide the scanner across the forehead as directed and read the displayed temperature.
Armpit Temperature
- Switch on the digital thermometer. Place the thermometer securely under the armpit, ensuring it is in direct contact with skin, not clothing.
- Hold the thermometer firmly in place until it beeps, signaling the measurement is complete.
- Take out the thermometer and read the temperature.
Ear Temperature
- Turn on the ear thermometer. Carefully position it within the ear canal, inserting only as far as instructed by the device’s guidelines.
- Hold the thermometer steadily in place until a beep indicates the reading is finalized.
- Remove the thermometer and record the temperature.
