Fevers are a symptom, signaling that your body is fighting an infection or an illness. Commonly, a fever will come before other symptoms such as cough, runny nose, earache, or rash, especially in children. More often than not, fevers are due to viral infections but fevers will also come along with bacterial infections as well. While fevers can be uncomfortable, they are typically a natural response your body has in order to create an inhospitable environment to whatever “bug” is trying to make you sick. To read more about the purpose of a fever, check out THIS blog post. Temperature ranges can vary depending on the age of the person and it is important to be aware of what is normal.

Body Temperature Ranges by Age

Our normal body temperature sits around 98.6°F or 36°F. However, it's essential to recognize that a "normal" body temperature can vary by age. Here are the typical temperature ranges for different age groups:

1. Infants (0-2 years old):

- Normal temperature range: 97.8°F to 100.4°F (36.5°C to 38°C)

- A fever is usually defined as a temperature above 100.4°F (38°C). If the child is under the age of 3 months, a fever should be taken seriously and a call to your doctor is warranted.

2. 3+ years old:

- Normal temperature range: 97°F to 99°F (36.1°C to 37.2°C).

- A fever is usually defined as a temperature above 100.4°F (38°C).

The Best Way to Take a Temperature Based Upon Age

The accuracy of the reading can vary slightly with different methods. Always follow the manufacturer's instructions for the specific thermometer being used, and make sure it's appropriate for the age group in question.

For infants and young children, especially, it's crucial to exercise caution and ensure that the thermometer is used safely to avoid injury or discomfort. Always clean and sanitize the thermometer before and after use to prevent the spread of germs.

The following outlines which methods of taking a temperature is most appropriate depending on the age of the person.

Birth to 3 months:
- Rectal Temperature: This method is considered the most accurate for infants. Use a digital thermometer and apply a small amount of lubricant to the tip. Gently insert it about half an inch into the baby's rectum. Ensure the baby is calm and held securely during the process.
3-6 months: When in doubt, the rectal temperature is the most accurate, but the following are additional ways you can take a temperature in this age group.
- Axillary (Underarm) Temperature: Though not as accurate as rectal methods, underarm temperature can be used for children. Place the thermometer under the armpit and ensure good contact with the skin.
-Temporal Artery (Forehead) Thermometer: Sources do suggest that a temporal artery thermometer might also provide accurate readings in infants older than 3 months old. This can be used as a first pass to assess for a temperature before doing a rectal temperature for a more accurate reading if fever is noted.
6 months - 3 years: When in doubt, the rectal temperature is the most accurate. However, in addition to the above temperature taking methods, you can add the following way to take a temperature on children older than 6 months.
- Ear (Tympanic) Thermometer: Ear thermometers are quick and non-invasive, making them a popular choice for children. Ensure that the ear canal is free from earwax, and follow the manufacturer's instructions for accurate results. This method should not be used until a child is older than 6 months old due to the size of the external ear canal.
4 years and older. By age 4, most kids can hold a digital thermometer under the tongue for the short time it takes to get an oral temperature reading. You can also use a digital thermometer to take an armpit temperature, or use a temporal artery thermometer or a digital ear thermometer to take a temperature of this age group.

When to Take Action on A Fever

There are a lot of myths and opinions around fevers and it can make it a stressful situation, especially as a parent to a young child. Seattle Children’s Hospital has a great article sorting fact vs myth when it comes to evaluating fevers in THIS article. For example, did you know that the brain has a natural turn-off mechanism for fevers that has been recognized since the 1940s? Fevers rarely exceed the body's natural fever cut-off point of 105°F which is not high enough to cause brain damage. Certain medications or drugs, nervous system disorders, or pre-existing conditions that affect brain function therefore overriding this natural cut off point can put someone at risk of a temperature over 108°F which can then cause brain damage or coma. Environmental factors can also make the body heat up too much such as over dressing/swaddling a baby or leaving someone in a hot car or enclosed area, but this is different than a fever response. There is nothing inherently dangerous about fever. The concern should be more to do with the underlying infection and making sure to avoid dehydration.

Here are some fast facts for when to seek medical help:

In children under the age of 3 months but especially under the age of 1 month, a fever (temperature greater than 100.4°F) can be very serious due to the state of their developing immune system making them more prone to bacterial infection. This age group is also at a higher risk of infection due to the potential of picking up an infection in the hospital or from a communicable vaginal infection from the birthing mother. and your doctor should be made aware of it so that you can take the appropriate steps.
For other age groups, the height of a fever actually has little relationship to the severity of the illness. Kids can have more serious illnesses with lower temperatures, and have common upper respiratory viral infections with a high fever. Therefore, monitoring other symptoms and their progression is more important. Symptoms to be on the lookout for include:
- Dehydration: This is a large concern, especially if a child is not taking fluids in or not urinating a normal amount.
- Stiff neck along with persistent vomiting and/or a severe headache: This can be a sign of a rare illness known as meningitis. This is a medical emergency and should receive swift medical intervention.
- Pain: Especially in the ear or belly. If pain becomes severe, this should be taken seriously and be evaluated my a medical professional.
- Energy: Low energy is a normal part of being sick. However, if the person who is ill is having a hard time waking up, seems weak or limp, or can’t make eye contact, this is a sign that something more serious is going on and should be evaluated by a medical professional.
- No symptoms: If the classic cold symptoms don’t come along with a fever, a urinary tract infection may be to blame, especially in children.
- Fevers greater than 104°F: For me and my loved ones, this is when I start getting concerned, even though I know about the natural fever shut off point. Fevers that get to 104°F+ is when I start recommend taking measures to lower a fever which I outlined in THIS blog post.
- Length of a fever: If a fever lasts for more than 3-5 days, even if not continuous, this should be evaluated.
- Intuition: We can never underestimate our own “gut feeling” about something. When it doubt, seek help even if the purpose to to lay your own concerns to rest.

Fevers are the body's natural response to infection or illness, and in most cases, they can be managed effectively at home using a combination of rest, hydration, and over-the-counter medications. Holistic remedies can also provide comfort during this time. However, it is crucial to monitor the temperature and be aware of when to seek medical help, especially in cases of high or prolonged fevers and severe accompanying symptoms. Always consult a healthcare professional for personalized advice and guidance when dealing with fevers, especially in infants and young children.

References:

To read more about fevers, check out our other articles:

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