In infants, a fever isn’t an illness — it’s a symptom of one. Typically, if your baby has a fever, it means he has picked up a cold or other viral infection. Other less common causes of a fever in infants are bacterial infections such as a urinary tract infection or a more serious infection such as meningitis.
Other causes of fever in babies include:
- Reaction to a vaccination
- Becoming overheated from being dressed too warmly or spending time outside on a hot day
What are the signs of a fever?
The most common signs of fever in young babies are a warm forehead or excessive crankiness. It is important to note that your baby can still have a fever if they don’t have a warm forehead.
Other symptoms associated with fever in babies include:
- poor sleeping
- poor eating
- lack of interest in play
- convulsion or seizure
- rapid breathing
Taking a babies temperature
You can take a child’s temperature a few different ways, such as via the rectum (rectally), mouth (orally), ear, under the arm (axillary), or at the temples. The American Academy of Pediatrics (AAP) recommends only using digital thermometers in children. Mercury thermometers should not be used because they pose a risk of mercury exposure and poisoning if they break.
Rectal thermometers provide the most accurate temperature readings.
How to take a rectal temperature
- Make sure the thermometer is clean. Wash it with soap and water or wipe it off with rubbing alcohol.
- Lay your baby on their belly or on the back with legs bent into the chest.
- Apply a little bit of petroleum jelly around the thermometer bulb and gently insert it about 1 inch into the rectum opening.
- Hold the digital thermometer in place for about two minutes until you hear the “beep.” Then gently remove the thermometer.
What temperature means it’s a fever?
0-1 month: 100.4 F or higher (rectal)– Call your doctor immediately. A baby this young needs to be checked for serious infection or disease.
3-6 months: 102 F (38.9 C) or higher (rectal). If your baby is 3 months old or older, this is not an emergency, call your doctor for a consultation, but remember, the most important thing is how he looks and acts.
6-24 months: 102 F (38.9 C) (rectal) that lasts longer than one day but shows no other signs or symptoms, contact the doctor. If your baby also has other signs or symptoms, such as a cold, cough or diarrhea, you might contact the doctor sooner based on their severity.
Note for 3 months+: You know your baby best. If he appears well and is taking fluids, there’s no need to call the doctor unless the fever persists for more than 24 hours or is very high. Ask your doctor for additional guidance: For example, the doctor may suggest calling right away if your baby’s fever reaches 104 degrees, regardless of symptoms.
When to Call Your Doctor
According to the AAP, call your doctor if your baby:
- Is under 3 months old and has a fever; if your baby is under 1 month of age and has a fever, it is considered an emergency. Seek immediate medical care.
- Is lethargic and not responsive
- Has problems breathing or eating – Sometimes rapid breathing is a result of the fever itself. Sometimes it’s the result of insufficient oxygen getting to the lungs, as a result of wheezing or pneumonia. Note: If rapid breathing goes away when the fever is reduced with Motrin/Tylenol, I’d attribute the rapid breathing to the fever in this case – if it does not go away see your healthcare provider immediately.
- Has a rash
- Shows signs of dehydration, such as fewer wet diapers, dry mouth, no tears with crying, or sunken soft spot on the head
- Has a seizure
Bringing a fever down in babies over 3 months
- Bathe your child with lukewarm water – make sure it is not too cold, you need to bring the fever down gradually, sudden temperature changes may be harmful to babies.
- Dress your baby in a light layer of clothes.
- Give your baby enough fluids to avoid dehydration. Those fluids should be breast milk, formula, an electrolyte solution, or water depending on the baby’s age. Contact your pediatrician for guidelines. A dehydrated baby may have fewer wet diapers (less than 1 every 6 hours), no tears with crying, or a dry mouth.
- If your doctor says it is OK, you can give your baby children’s Tylenol or ibuprofen (Advil or Motrin). (see medication below)
- Never give babies aspirin for a fever because of the risk for a rare but potentially dangerous condition called Reye’s syndrome.
**Do not give a baby under 6 months of age Advil, Motrin, or other medicines that contain ibuprofen. Be sure to ask your doctor about the dosage as the dosage rules keep changing. Also for really high fevers you may be told to alternate Tylenol and Motrin – giving Tylenol every 4 hours and Motrin every 6.
*note some medications come in a concentrated form so check the variant on the dosage chart.
If you are concerned about your baby’s fever, call your health care provider for advice and reassurance.
Your baby seems sick and his temperature is lower than normal, less than 97 F
Very young babies sometimes become cold rather than hot when they’re ill – it is important to note that if you have given your baby Tylenol or Motrin that their temperature my drop below 97 F briefly as their body is over compensating the fever reduction in tandem with the medicine and they should normalize within 15 minutes and you should take their temperature again and if it is still low consult your physician.
Which fever-reducing medicines are safe for babies 0-24 months?
If your baby uncomfortable because of a fever and your doctor says it’s okay, you can use infant acetaminophen or ibuprofen to bring down your baby’s temperature. (Ibuprofen isn’t recommended for babies under 6 months or for those who are dehydrated or have persistent vomiting.)
Be very careful when administering medicine to your baby. His weight will determine the right dose. (be sure to check dosing charts with your doctor because the dosing has changed – see the links above for the current charts from the AAP).
Always use the measuring device that comes with the medicine to give your baby exactly the right amount. Don’t give fever-reducing medicine more often than is recommended.
The directions will probably say that you can give acetaminophen every four hours (up to a maximum of five times per day) and ibuprofen every six hours (up to a maximum of four times per day). Never give your baby aspirin. Aspirin can make a child more susceptible to Reye’s syndrome, a rare but potentially fatal disorder.
Tips on giving your baby fever-reducing medication
If you haven’t already noticed babies hate taking medicine. For such young beings it is amazing that they are able to hold their mouth closed so tight that need the jaws of life to open it or that they can hold medicine in their mouth for a prolonged period of time, only to spit it out once you think you got it all in. Here are a few tips on giving your baby medicine:
- Hold baby flat on their backs.
- Put the syringe into their mouths pointed to the back corner of their cheek. Note: if you point it directly down their throats they will choke and likely throw the medicine back up on you. However if you put the syringe into the front of their mouth they’ll simply push the medicine back out with their tongue.
- If your baby is a ‘spitter’ squeeze his cheeks together, this makes it difficult to spit the medicine back up
- Hold their nose or insert a pacifier into their mouth (it makes them swallow – we find the nose holding is the best)
- If you can find the concentrated drops you may have more luck because there is less volume to administer
What should I do if my child has a seizure from his high fever?
Fevers sometimes cause febrile seizures in babies and young children. They’re most common in children between the ages of 6 months and 5 years.
A child having this type of seizure may roll his eyes, drool, or vomit. His limbs may become stiff and his body may twitch or jerk. In most cases, the seizures are harmless, but that doesn’t make it any less terrifying if your baby’s having one.
Read more about febrile seizures and how to handle them.