Fever and Illness: When to Seek Care

An independent educational resource prepared by Mark M. Simonian, MD, FAAP

Sources checked: August 2, 2026     |     Medical review completed

This page is for general education only and does not replace individualized medical advice. This resource does not establish a doctor-patient relationship. For questions about your own child, contact your child's current healthcare professional.

Magnolia Pediatrics, Valley Children's Healthcare

2497 E. Herndon Avenue, Suite 101, Clovis, CA 93611     |     559-538-3070

Use this guide to decide how urgently your child may need medical help. Age, breathing, alertness, hydration, and other symptoms matter at least as much as the temperature number.

Urgent Warning Signs — Check This First

When in doubt about a life-threatening emergency, call 911.

CALL 911 NOW

  • Not breathing, severe trouble breathing, unable to speak or cry because of breathing difficulty, blue or gray lips or face, or limp and unresponsive

  • A seizure lasting 5 minutes or longer, repeated seizures without recovery, or a seizure with breathing trouble, blue or gray color, or a serious injury

  • Possible heatstroke after being in a very hot place, especially with confusion, collapse, seizure, or inability to wake

  • You believe your child is in immediate danger

GET EMERGENCY MEDICAL CARE NOW

  • A baby younger than 3 months (12 weeks) with a rectal temperature of 100.4°F (38.0°C) or higher, even if the baby otherwise looks well. Unless a healthcare professional tells you otherwise, do not give fever medicine before the baby is evaluated.

  • Fever with ribs pulling in, very fast or labored breathing, grunting, persistent wheezing or stridor, or difficulty speaking, crying, feeding, or drinking because of breathing trouble

  • Hard to wake, not alert when awake, confusion, unusual behavior, extreme weakness, or inability to stand or move normally

  • A stiff neck, severe headache, strong sensitivity to light, or a bulging soft spot in an infant

  • A new purple, blood-colored, or bruise-like rash that is not explained by an injury

  • Repeated vomiting or diarrhea with inability to keep fluids down, very little urine, severe dry mouth, no tears, sunken eyes, or a child too weak or drowsy to drink

  • A first seizure associated with fever, even if it stopped before 5 minutes

CONTACT YOUR CHILD'S HEALTHCARE PROFESSIONAL TODAY

  • A child 3 to 6 months old with a fever, particularly a temperature of 101°F (38.3°C) or higher or any ill appearance

  • A temperature repeatedly above 104°F (40°C) in a child of any age

  • Your child looks very ill, is unusually sleepy or irritable, is getting worse, or still acts sick when the temperature comes down

  • Fever with severe ear or throat pain, painful urination, repeated vomiting or diarrhea, an unexplained rash, or significant localized pain

  • Signs of dehydration such as substantially fewer wet diapers or trips to the bathroom, a dry or sticky mouth, no tears, or unusual sleepiness

  • Fever in a child with sickle cell disease, cancer, an organ transplant, immune-system problems, complex chronic illness, or medicines that suppress immunity; follow the child's individual illness plan

  • Fever lasting more than 24 hours in a child younger than 2 years, more than 3 days in a child age 2 years or older, or returning after being gone for more than 24 hours

  • You are worried or uncertain about what you are seeing

Sources and medical review

What Counts as a Fever?

A fever is a rise in body temperature, most often caused by the body's response to an infection. A measured temperature of 100.4°F (38.0°C) or higher is generally considered a fever, but the measurement site and device matter. For babies younger than 3 months, the urgent threshold on this page is a rectal temperature of 100.4°F (38.0°C) or higher.

Fever is a symptom, not a diagnosis. In children older than 3 months, a higher number does not automatically mean a more dangerous illness. How the child breathes, drinks, urinates, wakes, interacts, and changes over time is often more informative.

Fever caused by illness is different from overheating or heatstroke. A child who becomes confused, collapses, has a seizure, or cannot be awakened after heat exposure needs emergency help.

Sources and medical review

Measuring Temperature

Use a digital thermometer and follow its instructions. Do not use a mercury thermometer. Feeling the forehead is not accurate enough when a fever decision matters.

Choose a method appropriate for age

  • Younger than 3 months: a rectal temperature provides the most accurate reading. If you are unsure how to take it safely, contact a healthcare professional.

  • Forehead (temporal artery): may be used at any age when the device instructions are followed.

  • Ear: may be used from 6 months of age; placement matters and ear readings are not reliable in younger infants.

  • Oral: generally appropriate from about age 4 years when the child can keep the thermometer correctly under the tongue.

  • Armpit: useful for screening but is the least accurate. Confirm a concerning result with a more reliable method or professional guidance.

Write down the exact temperature, the time, and where and how it was measured. Report that information without adding or subtracting degrees.

Sources and medical review

Look at the Child, Not Only the Number

More reassuring signs

  • The child is alert, recognizes and interacts with caregivers, and has periods of improved energy

  • Breathing is comfortable without pulling in between the ribs, grunting, or unusual color

  • The child drinks and urinates reasonably well

  • Pain is mild and the child can be comforted

Concerning changes

  • The child is difficult to wake, confused, unusually weak, inconsolable, or steadily worsening

  • Breathing becomes faster, noisier, or more difficult

  • Drinking and urination decrease substantially, or vomiting prevents fluids from staying down

  • A new rash, stiff neck, severe headache, severe localized pain, or other major new symptom appears

Sources and medical review

Safe Home Care When No Warning Signs Are Present

  • Offer fluids frequently. Continue breast milk or formula for infants. Older children may take small, frequent sips of appropriate fluids.

  • Let the child rest. Do not force solid food if the child is drinking adequately.

  • Use one comfortable layer of clothing. Add a light blanket for chills, and remove it when the chills stop.

  • A lukewarm bath may be used for comfort, but stop if the child shivers. Do not use ice, cold-water baths, rubbing alcohol, or alcohol baths.

  • The goal is comfort and hydration, not forcing the temperature to normal. Check the child periodically, including during the night when the illness is new or concerning.

Sources and medical review

Fever Medicines: Safety First

Fever medicine is mainly used to improve comfort. Not every fever needs medicine, and medicine does not treat the infection causing the fever.

  • Do not give fever medicine to a baby younger than 12 weeks before medical evaluation unless a healthcare professional specifically instructs you to do so.

  • For children younger than 2 years, obtain dosing guidance from the child's healthcare professional. Do not use ibuprofen in a child younger than 6 months unless the child's doctor directs it.

  • Never give aspirin to a child or teenager for fever or pain unless it was specifically prescribed for a medical condition.

  • Read the Drug Facts label every time. Use the child's current weight when directed, use the supplied oral syringe or dosing cup, and never use a kitchen spoon.

  • Avoid giving more than one product containing acetaminophen at the same time. Combination cough-and-cold products may contain a fever reducer.

  • If you are unsure about the product, concentration, dose, timing, or interaction with another medicine, ask a pharmacist or the child's healthcare professional before giving it.

Sources and medical review

Febrile Seizures

Febrile seizures can occur in otherwise healthy children, usually between 6 months and 5 years of age. Most are brief and do not cause brain damage, but a first seizure needs prompt medical assessment. Fever medicine does not reliably prevent febrile seizures.

What to do during a seizure

  • Place the child on the floor or a bed away from hard or sharp objects.

  • Turn the child's head to the side so saliva or vomit can drain.

  • Do not hold the child down and do not put anything in the mouth.

  • Time the seizure and watch breathing and skin color.

  • Call 911 if it lasts 5 minutes or longer, repeats without recovery, causes breathing trouble or blue or gray color, or results in an injury.

  • If a first seizure stops before 5 minutes, obtain prompt medical evaluation to identify the cause of the fever.

Sources and medical review

Preparing to Contact a Healthcare Professional

Have the following information ready when possible:

  • The child's age, weight, medical conditions, medicines, allergies, and immune-system risks

  • The highest temperature, when it was measured, and the thermometer method used

  • How long the fever has lasted and whether it went away and returned

  • Breathing, alertness, drinking, urine or wet diapers, vomiting, diarrhea, rash, pain, and other symptoms

  • Any fever or pain medicine already given, including the product, concentration, amount, and time

  • Recent vaccines, travel, known illness exposures, injuries, or heat exposure

If your child has an individualized plan for asthma, seizures, sickle cell disease, cancer treatment, immune suppression, or another high-risk condition, follow that plan and contact the responsible clinical team promptly.