Should Your Child See a Doctor?


This Care Guide Covers

  • Fever is the only symptom. Your child has a fever if:
  • Rectal, Ear or Forehead temperature: 100.4° F (38.0° C) or higher
  • Oral or Mouth temperature: 100° F (37.8° C) or higher
  • Under the arm (Armpit) temperature: 99° F (37.2° C) or higher
  • Caution: Ear temperatures are not accurate before 6 months of age.
  • Caution: Forehead temperatures must be digital. Forehead strips are not accurate.

See Other Care Guide If

  • Other symptom is present with the fever, see that guide. Examples are COLDS, COUGH, SORE THROAT, EARACHE, SINUS PAIN, DIARRHEA, VOMITING. (Note: If crying is the only other symptom, stay in Fever guide).
  • Fever started within 24 hours of getting a shot. See IMMUNIZATION REACTIONS.
  • Fever started 6-12 days after measles shot. See IMMUNIZATION REACTIONS.
  • Fever started 17-28 days after chickenpox shot. See IMMUNIZATION REACTIONS.

Health Information

Causes of Fever

  • Overview. Almost all fevers are caused by a new infection. Viruses cause 10 times more infections than bacteria. The number of germs that cause an infection are in the hundreds. Only a few common ones will be listed.
  • Viral Infections. Colds, flu and other viral infections are the most common cause. Fever may be the only symptom for the first 24 hours. The start of viral symptoms (runny nose, cough, loose stools) is often delayed. Roseola is the most extreme example. Fever may be the only symptom for 2 or 3 days. Then a rash appears.
  • Bacterial Infections. A bladder infection is the most common cause of silent fever in girls. Strep throat is also a common cause of unexplained fever.
  • Sinus Infection. This is a complication of a cold. The main symptom is the return of fever after it has been gone for a few days. The sinus congestion also changes to sinus pain. Color of nasal discharge is not very helpful.
  • Vaccine Fever. Fever with most vaccines begins within 12 hours. It lasts 2 to 3 days. This is normal and harmless. It means the vaccine is working.
  • Newborn Fever (Serious). Fever that occurs during the first 3 months of life can be serious. All of these babies need to be seen as soon as possible. The fever may be due to sepsis (a bloodstream infection). Bacterial infections in this age group can get worse quickly. They need rapid treatment.
  • Meningitis (Very Serious). A bacterial infection of the membrane that covers the spinal cord and brain. The main symptoms are a stiff neck, headache and confusion. Younger children are lethargic or so irritable that they can't be consoled. If not treated early, can suffer brain damage.
  • Overheated. The fever is usually low grade. Can occur during heat waves or from being overdressed. The temp becomes normal in a few hours after moving to a cooler place. Can also occur during hard exercise. Fever goes away quickly with rest and drinking extra fluids.
  • Not Due to Teething. Teething does not cause fevers.

Fever and Crying

  • Fever on its own shouldn’t cause much crying.
  • Frequent crying in a child with fever is caused by pain until proven otherwise.
  • Hidden causes can be ear infections, kidney infections, sore throats and meningitis.

Roseola: Classic Cause of Unexplained Fever in Young Children

  • Most children get Roseola between 6 months and 3 years of age.
  • Cause: Human herpes virus 6
  • Rash: Pink, small, flat spots on the chest and stomach. Rash is the same on both sides of the body.
  • Then spreads to the face.
  • Classic feature: 2 or 3 days of high fever without a rash or other symptoms.
  • The rash starts 12 to 24 hours after the fever goes away.
  • The rash lasts 1 to 3 days.
  • By the time the rash appears, the child feels fine.

Normal Temperature Range

  • Rectal. A reading of 98.6° F (37° C) is just the average rectal temp. A normal low can be 96.8° F (36° C) in the morning. It can change to a high of 100.3° F (37.9° C) late in the day. This is a normal range.
  • By mouth. A reading of 97.6° F (36.5° C) is just the average mouth temp. A normal low can be 95.8° F (35.5° C) in the morning. It can change to a high of 99.9° F (37.7° C) late in the day. This is a normal range.

Return to School

  • Your child can go back to school after the fever is gone. Your child should feel well enough to join in normal activities.

When To Call Your Doctor

Call 911 Now (your child may need an ambulance) If

  • Not moving or too weak to stand
  • Can't wake up
  • Trouble breathing with bluish lips or face
  • Purple or blood-colored spots or dots on skin
  • You think your child has a life-threatening emergency

Go to ER Now If

  • Stiff neck and can’t touch chin to chest
  • Age less than 1 year and soft spot bulging or swollen
  • Hard to wake up
  • Not alert when awake
  • Acts or talks confused
  • Had a seizure with the fever

Call Your Doctor Now (night or day) If

  • Trouble breathing
  • Great trouble swallowing fluids or spit
  • Age less than 12 weeks old with any fever. (Caution: Do NOT give your baby any fever medicine before being seen)
  • Fever more than 104° F (40° C)
  • Nonstop crying or cries when touched or moved
  • Won't move an arm or leg normally
  • Dehydration suspected. (No urine in over 8 hours, dark urine, very dry mouth and no tears)
  • Burning or pain when passing urine
  • Weak immune system. (Such as sickle cell disease, HIV, cancer, organ transplant, taking oral steroids)
  • Your child looks or acts very sick.
  • You think your child needs to be seen, and the problem is urgent.

Call Your Doctor Within 24 Hours If

  • Age 3-6 months old with fever
  • Age 6-24 months old with fever that lasts more than 24 hours. There are no other symptoms (such as cough or diarrhea).
  • Fever lasts more than 3 days
  • Fever returns after gone for more than 24 hours
  • You think your child needs to be seen, but the problem is not urgent

Call Your Doctor During Weekday Office Hours If

  • You have other questions or concerns

Parent Care at Home If

  • Fever with no other symptoms and your child acts mildly ill.

Care Advice for Fever

  1. What You Should Know About Fever:
    • Having a fever means your child has an infection.
    • It's most likely caused by a virus.
    • You may not know the cause of the fever until other symptoms develop. This may take 24 hours.
    • Most fevers are good for sick children and help the body fight infection.
    • Use the ranges below to help put your child's level of fever into perspective:
    • 100°-102°F (37.8° - 39°C) Slight fever: helpful, good range
    • 102°-104°F (39 - 40°C) Average fever: helpful
    • Over 104°F (40°C) High fever: causes discomfort, but harmless
    • Over 106°F (41.1°C) Very high fever: important to bring it down
    • Over 108°F (42.3°C) Harmful fever: fever itself can cause brain damage
  2. Treatment for All Fevers: Extra Fluids and Less Clothing
    • Offer your child lots of cold fluids to drink. Reason: Good hydration replaces sweat. It also improves heat loss from the skin.
    • For babies, dress in 1 layer of light weight clothing and sleep with 1 light blanket. Do not wrap in too many blankets. This may make the fever higher. Caution: Babies can get over heated easily. They can't take their clothes or blankets off if they are too hot.
    • For fevers 100°-102° F (37.8° - 39°C), fever meds are rarely needed. Fevers of this level don't cause discomfort. They do help the body fight the infection.
  3. Fever Medicine:
    • Fevers only need to be treated with medicine if they cause discomfort. Most often, that means fevers above 102°F (39°C).
    • For fevers above 102° F (39° C), give an acetaminophen product (such as Tylenol).
    • Another choice is an ibuprofen product (such as Advil). See Dose Tables.
    • Goal of treatment: Bring the temperature down to a comfortable level. Most often, the fever meds only lower the fever by 2° to 3° F (1 - 1.5° C). They do not bring it down to normal.
    • Do not use aspirin. Reason: Risk of Reye syndrome, a rare but serious brain disease.
    • Do not use both acetaminophen and ibuprofen together. Reason: Not needed and a risk of giving too much.
  4. Sponging With Lukewarm Water:
    • Note: Sponging is an option for high fevers, but not required.
    • When to Use: Fever above 104° F (40° C) AND doesn't come down with fever meds. Always give the fever med first.
    • How to Sponge: Use lukewarm water (85 - 90° F) (29.4 - 32.2° C). Sponge for 20-30 minutes.
    • If your child shivers or becomes cold, stop sponging. Other option: You can also make the water warmer.
    • Caution: Do not use rubbing alcohol. Reason: Can cause a coma.
  5. Return to School:
    • Your child can return to school after the fever is gone. Your child should feel well enough to join in normal activities.
  6. What to Expect:
    • Most fevers with viral illnesses range between 101° and 104° F (38.4° and 40° C).
    • They may last for 2 or 3 days.
    • They are not harmful.
  7. Call Your Doctor If:
    • Fever goes above 104° F (40° C)
    • Any fever occurs if less than 12 weeks old
    • Fever without a cause lasts more than 24 hours (if age less than 2 years)
    • Fever lasts more than 3 days (72 hours)
    • Your child becomes worse

Remember! Contact your doctor if your child develops any of the "When to Call" symptoms.


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This information is not intended to be a substitute for professional medical advice. It is provided for educational purposes only. You assume full responsibility for how you choose to use this information.

Author: Barton D. Schmitt, M.D.

Copyright 1994-2015 Barton D. Schmitt, MD. All rights reserved.