How to Know Fever in Children: When to Worry

Fever in children is usually a normal immune response to infection, not an illness by itself. A temperature of 100.4°F (38°C) or higher in a baby younger than 3 months requires a prompt call to a pediatrician , while severe symptoms or a child who seems seriously ill may require emergency care.

What counts as a fever in children?

A fever is a body temperature of 100.4°F (38°C) or higher . Temperature readings can vary depending on the measurement method, so follow the thermometer’s instructions and note the number, time, and method used.

The temperature is only one part of the picture. Your child’s age, symptoms, behavior, breathing, hydration, and overall appearance also help determine whether medical advice is needed. A child who is responsive, drinking fluids, and resting comfortably may need supportive care and observation. A child who looks very ill needs prompt attention, even if the temperature is not extremely high.

For additional guidance, visit the practice’s Is Your Child Sick?® resource or contact our Fresno pediatric office.

Why does a fever help fight infection?

Fever is part of the body’s immune response. Raising body temperature can make conditions less comfortable for some germs and helps activate immune defenses. Because of this, the goal is not always to make the temperature completely normal.

The goal of care is to help your child rest, drink, and remain comfortable while you watch for changes. Fever-reducing medicine may improve comfort, but it does not treat every cause of fever or replace medical evaluation when warning signs are present.

How can you care for a child with a fever at home?

Comfort care is often the first step when your child is otherwise alert and able to drink:

• Offer frequent fluids, including small amounts more often if your child feels nauseated.
• Encourage rest and dress your child in light, comfortable clothing.
• Keep the room comfortably cool; avoid ice baths, alcohol rubs, or excessive bundling.
• Check on your child regularly and watch behavior, breathing, urination, and fluid intake.
• Use fever medicine only as directed and only when appropriate for your child’s age and health history.

Ask us about weight-based dosing before giving medicine. The correct dose depends on your child’s weight and the specific product concentration. Do not guess, combine products without checking their ingredients, or use a kitchen spoon for measurement. Our Medicine Dosages resource and information about acetaminophen and ibuprofen can help you prepare questions for our team.

When should you call the pediatrician about a fever?

Call promptly if a baby under 3 months old has a temperature of 100.4°F or higher . Young infants need medical guidance because serious infections can develop without many other obvious symptoms.

For children older than 3 months, call when you are concerned about your child’s appearance, symptoms, hydration, or recovery. It is also reasonable to call if:

• Your child is difficult to wake, unusually confused, or much less responsive.
• Breathing is hard, fast, noisy, or visibly labored.
• Your child cannot keep fluids down or is urinating much less than usual.
• A severe headache, stiff neck, seizure, concerning rash, or significant pain occurs.
• The fever or illness is worsening, keeps returning, or your child is not improving.
• Your child has a chronic condition, takes medicines that affect immunity, or you are unsure what to do.

Our Same-Day Sick Child Visits page explains how our pediatric practice can help families with acute concerns. When you call, be ready to share your child’s age, temperature, measurement method, symptoms, fluid intake, urination, medicines given, and the time symptoms began.

When should a child with a fever go to the ER?

Go to the emergency room or call emergency services for an immediate, life-threatening emergency. Examples include severe trouble breathing, blue or gray lips or skin, unresponsiveness, a seizure that does not stop, or a child who cannot be awakened.

Emergency evaluation is also appropriate when your child appears seriously ill and is rapidly worsening, has signs of severe dehydration, or has a serious injury or symptom that cannot safely wait for an office call. If you are uncertain whether the situation is an emergency, choose safety and seek urgent help.

For information about local hospital and urgent-care options, review our Hospital pages. This page does not replace emergency services when your child is in immediate danger.

Should you treat the number or your child’s comfort?

Treat your child’s comfort and condition, not only the thermometer reading. A fever can be high while a child remains interactive and hydrated, or a lower temperature can occur with a child who looks very sick. Monitor the whole picture and contact us when your instincts tell you something is wrong.

Never give aspirin to a child unless specifically instructed by a medical professional. Ask us before giving medicine to an infant, before alternating medicines, or if your child has allergies, kidney problems, dehydration, or other health concerns.

Frequently asked questions about fever in children

What should parents do next?

Fever in children is often the body’s way of responding to infection, and comfort, fluids, observation, and correct weight-based dosing are important. Call promptly for a temperature of 100.4°F or higher in a baby under 3 months, and seek emergency care for severe or rapidly worsening symptoms. For questions or a sick-child concern, book a visit with our Fresno pediatric practice or contact us .