Call our office or page operator (after hours) if your baby is younger than three months of age and develops a fever (rectal temperature equal to or more than 100.4°F). Do not give Tylenol to a baby less than three months old without talking to us first. The medicine can confuse the situation by altering the fever’s course.
For older infants, we are more concerned about how your child looks and acts rather than the height of the fever.
Always accurately record temperatures with a digital thermometer. The best place to check is in the rectum (especially for babies less than three months old) or axillary if > one-year-old. Write this number down on a piece of paper. Fever is defined as any temperature more than 100.4° F for infants less than three months old. For older children (children older than three months), we consider 101°F a fever.
Taking a Rectal Temperature
- Lubricate the tip of the thermometer with a water-soluble lubrication. (KY, Vaseline, etc.)
- Place your baby face down across your lap, supporting his head, or lie him down on a firm flat surface such as a changing table.
- Press the palm of one hand firmly against your baby’s lower back to hold him still.
- Using your other hand, insert the lubricated thermometer through the anal opening, about 1/2 to 1 inch into the rectum. Stop at less than 1/2 inch if you feel any resistance.
- Steady the thermometer between your second and third fingers as you cup your hand against your baby’s bottom. Soothe your baby and speak to him quietly as you hold the thermometer in place.
- Wait until you hear the appropriate number of beeps or other signals that the temperature is ready to be read. Read and record the number on the screen, noting the time of day that the reading was taken.
Treatments for Fever
Fever is not harmful itself; it is usually a symptom of an infection. It is a sign that your child’s body is fighting the infection. Treatments for fever offer only temporary relief. The decision to treat a fever should revolve around how the fever is affecting your child. If your child has a fever and feels great, medication is probably not necessary. Medicine might be warranted if he feels achy and weak or if your child also has a headache or a sore throat. Please do not treat the fever of a child less than three months old. We need to know about it. Should you decide to treat a fever, we recommend the following measures:
- Acetaminophen (Tylenol, for children any age) and ibuprofen (i.e. Advil or Motrin, for children older than six months of age) are excellent medicines for fever treatment. Studies have shown that selecting a single medicine and using it appropriately controls fever as well as alternating medicines. Therefore, we recommend using a single fever reducer every six hours. In general, ibuprofen is preferable as a first line medicine for fever because it lasts longer and controls aches and pains better than acetaminophen. If the fever returns before it is time to give ibuprofen again, you can then use acetaminophen to bridge the gap, if necessary. Again, do not use ibuprofen for children less than six months old.
- Do not use aspirin to treat a child’s fever. If your child vomits the fever medication, you can use rectal acetaminophen (Feverall) sold over-the-counter at the pharmacy.
- You also can give a lukewarm sponge bath for ten to twenty minutes (26-28C° is optimal) for comfort purposes. Repeat this every two hours as needed. Evidence shows this does not reduce fever, however it can be done for your child’s comfort.
Be certain that you are giving the right dose of medicine. This can be confusing as seen below:
Infant’s Unconcentrated Acetaminophen Drops* : 160mg/5ml
Children’s Acetaminophen: 160mg/5ml
Infant’s Ibuprofen Drops: 50mg/1.25ml
Children’s Ibuprofen: 100mg/5ml
*Concentrated Infant Acetaminophen drops (80mg/0.8mL) are no longer available
Do not use ibuprofen any closer than every six hours and do not use acetaminophen any closer than every four hours.
You can safely follow the dosing on the box. If you want to be safe and want to double check the dose, the general dosing of acetaminophen is 15mg per kg per dose or 7mg per pound per dose (2.2lbs = 1kg). The dosing of ibuprofen is 10mg per kg per dose or 4.5mg per pound per dose.
For more information on fever, see Fever in the Health Topics section.
When to call the on-call doctor
- If your child is younger than 3 months with a rectal temperature >100.4ºF
- If your child has a very high fever (>105ºF)
- If your child is inconsolable or unresponsive despite giving an adequate dose of a fever reducer
- If your child has a severe headache or stiff neck (in addition to a fever)
Fever reducers are only designed to make your child more comfortable. It will NOT stop your child from having a fever.
On average, fever reducers take up to one hour to work. Acetaminophen can last as long as 4-6 hours and can be safely given at any age. Ibuprofen can last as long as 6-8 hours and can be safely given to children 6 months of age.
With over-the-counter cold medicines, WHICH WE DO NOT RECOMMEND, avoid preparations which also contain acetaminophen or ibuprofen in order to minimize the chance of overdosing on a fever-reducing agent.