What to Know and Do About Fevers at Every Age

When you have a fever, you generally feel lousy — you might be tired, irritable, flushed, sweaty or achy. But it can be tough to figure out whether you can care for a fever at home or if you need medical attention. It’s even trickier when it’s your child who has a fever, especially a baby or toddler who can’t tell you how they feel.

David Kipp, MD, a pediatrician with Banner Urgent Care, explained more about fevers, what they could mean and what steps you should take if you’re caring for someone who has one.

“Fever is a sign, not a disease,” Dr. Kipp said. A fever tells you that something else is wrong. It’s often a sign of an infection, but other conditions such as autoimmune diseases, cancers and inflammation can also cause fevers. Fevers can affect people differently, depending on their age.

A fever happens when your body temperature goes above 98.6°F (37°C). A higher body temperature makes it harder for viruses and bacteria to survive. So when your body detects a threat, a part of your brain called the hypothalamus raises your body temperature.

Common causes of fevers

Infections are the top culprit when it comes to fevers. “Most infections, especially in children, are caused by viruses, which generally cannot be treated except for making the child comfortable until the virus infection runs its course,” Dr. Kipp said.

But some fevers are caused by conditions that can be treated with antibiotics or antiviral medications, such as:

Ear infections
Sinus infections
COVID-19
Pneumonia
Strep throat
Serious skin infections
Urinary tract infections
Influenza
Meningitis
Bacterial infections in the blood (sepsis)

If you or your child has symptoms that could be a sign of a treatable infection or an emergency, seek medical care quickly.

Get care right away for a fever along with:

Ear pain
Sinus pain
Deep productive cough
Sore throat
Pain or blood with urination
Chills and body aches during flu season
Neck stiffness
Headache
Trouble breathing
Seizure
Persistent vomiting
Confusion
Chest pain
A weakened immune system

If you or your child seem very sick or you’re concerned about a fever for any reason, reach out to a provider for advice. Trust your instincts.

What else is going on?

There are a few other things to look at along with a fever:

Other symptoms: “Fever evaluation should consider the whole child and other symptoms. A playful, smiling infant or young child with a fever who is eating and drinking fairly normally is much less concerning than a lethargic, fussy child who is not eating or drinking well,” Dr. Kipp said.
How high the fever is: “In older infants and children, the higher the fever, the more likely the child might have a serious infection that could require antibiotics. A general guideline is a fever over 103 to 104 degrees should be evaluated promptly,” Dr. Kipp said (see below for more specific advice based on age).
Immunizations: “A fever in an unimmunized infant or child could be a sign of a serious infection such as sepsis or bacterial meningitis,” Dr. Kipp said. Immunization prevents these germs from getting into the bloodstream or brain.

Fever at different ages

Here are some specific guidelines about fevers, based on age:

Infants under 3 months old

If you think a young baby has a fever, it’s best to check with a thermometer. A baby with a fever may feel warm or be fussy. “It’s difficult to determine if fever in an infant is due to a virus or a significant infection, even for physicians,” Dr. Kipp said.

Contact a health care professional if your infant has a temperature of 100.4°F (38°C) or higher. Since it can be hard to tell what’s causing your baby’s fever, you may need to get lab testing in an emergency department.

Babies 3 to 12 months old

For a baby 3 to 12 months old, check their temperature with a thermometer and contact a health care provider if it’s 102°F (38.9°C) or higher.

Children age 1 to 12

Contact a health care provider or go to urgent care for a fever above 102°F (38.9°C) that doesn't go down with fever-reducing medicine, or for any signs of dehydration such as dry mouth or fewer wet diapers.

Adolescents over age 12 and adults up to age 65

Compared to children, adolescents and adults might have more noticeable symptoms like body aches, fatigue and sweating. Adults tend to recognize fevers more easily and can often describe how they feel. In this age group, fevers are often caused by the flu, colds, COVID-19, urinary tract infections or pneumonia.

Seek medical advice or go to the emergency room for a fever above 103°F or 39.4°C that lasts more than 72 hours, symptoms that are getting worse or difficulty breathing, chest pain or confusion.

Get care right away for a fever of 104°F or 40°C or higher.

Adults over age 65

Seniors typically have a lower body temperature and may run a bit cooler than young adults, so it’s a good idea to have a baseline reading of your temperature that you can share with your health care provider for advice.

Because of other medical conditions and age, older adults can be more strongly impacted by bacterial and viral infections. Seek immediate medical help for a fever higher than 103°F or 39.4°C, if daily activities are difficult or if there is also a headache, severe shortness of breath, disorientation, chest pain, vomiting, convulsions or seizures.

How to treat a fever at home

A fever that doesn’t need medical care can still leave you or your child feeling icky. But not all fevers need to be lowered. Mild to moderate fevers may help the immune system work better.

In babies, you might be able to manage a fever at home if they don’t have other symptoms and they are feeding well and alert. In children and adults, you may be able to manage fevers with mild symptoms like cough, runny nose or mild body aches at home.

Here are some steps you can take to help you or your loved one stay comfortable and hydrated:

Drink plenty of fluids to prevent dehydration. In babies, that may mean breast milk or formula. Older children and adults may want water, herbal tea, diluted juice, clear broth, cool drinks or popsicles. Electrolyte solutions can help you stay hydrated. Avoid drinks with caffeine or alcohol, since they can dehydrate you.
Dress lightly, apply cool, damp cloths to the forehead and take lukewarm baths.
Encourage plenty of rest to help fight off infection.
Avoid strenuous activities that can raise body temperature.
If you need to lower the fever with medication, use acetaminophen (Tylenol) or ibuprofen (Advil or Motrin) as directed by a health care professional. Use infant, children or adult types of over-the-counter (OTC) medications based on the age and weight of the person with the fever. “Avoid aspirin under age 18 and ibuprofen under age 6 months,” Dr. Kipp said. Aspirin can cause Reye's syndrome in children. Ibuprofen is more likely to cause side effects in young babies.

The bottom line

It’s important to understand what causes fevers, when you should be concerned and when to get medical care. Whether it’s for infants, children, adolescents or adults, keep an eye on symptoms and contact your health care provider, an expert at Banner Health or an urgent care center for any symptoms that concern you.

Have you listened?

Fevers: What to Do and When to Worry