Fever in Children: Temperature Measurement, Safe Antipyretic Dosing, and Warning Signs
Teach that fever is a temperature of 100.4 F (38 C) or higher, and that any fever in an infant under 3 months (12 weeks) requires an immediate call to the provider or an emergency department visit. Dose acetaminophen by weight with the supplied measuring device, give ibuprofen only to children 6 months and older, and never give aspirin. Treat the child's comfort, not the number on the thermometer.
Who needs this teaching
Parents and caregivers of infants and children with an acute febrile illness. Fever is a regulated rise in the hypothalamic set point, usually in response to infection. The height of the fever does not reliably indicate the severity of the illness. The child's age, appearance, behavior, and hydration guide the response.
The priority teaching points
- Definition of fever. Fever is a temperature of 100.4 F (38 C) or higher. Record the temperature, the route, and the time.
- Measurement by age. For infants under 3 months, use a digital rectal thermometer, as the provider advises. Temporal artery (forehead) thermometers are used from 3 months, tympanic (ear) thermometers from 6 months, and oral thermometers from about 4 years. Axillary readings are for screening only. Never use a mercury thermometer.
- Infants under 3 months. Any temperature of 100.4 F (38 C) or higher in an infant under 3 months (12 weeks) requires an immediate call to the provider or an emergency department visit. Fever in a young infant indicates possible serious bacterial infection, such as urinary tract infection, bacteremia, or meningitis. Do not give an antipyretic before assessment unless the provider directs it.
- Comfort care. Offer frequent fluids: breast milk or formula for infants, and water or oral rehydration solution for older children. Dress the child in light clothing and encourage rest. Do not use cold baths, ice, or alcohol rubs. Cold causes shivering; alcohol causes toxicity through skin absorption.
- Antipyretic dosing. The goal of antipyretic therapy is comfort, not a normal temperature. Dose by current weight, not age. Acetaminophen is 10 to 15 mg/kg every 4 to 6 hours, with no more than 5 doses in 24 hours. Ibuprofen is 5 to 10 mg/kg every 6 to 8 hours, with no more than 4 doses in 24 hours, for children 6 months and older only. Use the oral syringe or cup supplied with the product, never a kitchen spoon. Check combination cold products for duplicate acetaminophen. Do not alternate the two drugs unless the provider directs it.
- Never aspirin. Do not give aspirin or other salicylates to children and teenagers. Aspirin during a viral illness, especially influenza or varicella, is associated with Reye syndrome (acute encephalopathy with liver failure).
Red flags the parent reports
| Call the provider the same day | Call 911 or the local emergency number |
|---|---|
| Temperature of 100.4 F (38 C) or higher in an infant under 3 months: call immediately or go to the emergency department | Respiratory distress, retractions, or cyanosis of the lips |
| Fever lasting more than 3 days (72 hours) | Child is difficult to arouse or does not respond normally |
| Fever lasting more than 24 hours in a child under 2 years | Nuchal rigidity (stiff neck) |
| Ear pain or dysuria | Seizure |
| No urine in 8 hours, dry mouth, or no tears when crying | Nonblanching purple rash (petechiae or purpura), a sign of meningococcemia |
Teach-back questions
- "Show me how you take your baby's temperature."
- "What temperature in your 6-week-old means you call right away?"
- "Show me how you measure the dose with this syringe."
- "Which fever medicine will you never give your child?"
- "Which signs mean you call 911?"
Teaching tips
- Write the child's weight, the product concentration, and the dose in milliliters on the handout.
- Observe a return demonstration of dose measurement with the supplied syringe.
- Ask about every product in the home, including combination cold medicines.
Read more on NCLEXPace
- Pediatric Dosing and Safe Dose Range Questions
- Pediatric Vital Signs by Age: The Only Table You Need
- Seizure Precautions and Status Epilepticus: What Never to Do
Sources
- Sullivan JE, Farrar HC; American Academy of Pediatrics Section on Clinical Pharmacology and Therapeutics; Committee on Drugs. Fever and Antipyretic Use in Children. Pediatrics. 2011;127(3):580-587.
- Pantell RH, et al. Clinical Practice Guideline: Evaluation and Management of Well-Appearing Febrile Infants 8 to 60 Days Old. Pediatrics. 2021;148(2):e2021052228.
- Children's Acetaminophen Oral Suspension and Children's Ibuprofen Oral Suspension: FDA Drug Facts labeling (DailyMed).
Why this matters for the NCLEX
Teaching is effective when the parent states, "I will call right away if my 6-week-old has a rectal temperature of 100.4 F," and "I will measure the acetaminophen with the syringe that comes in the box." Statements requiring further teaching include, "I will give baby aspirin for the fever," "I will sponge my child with rubbing alcohol," and "I will give ibuprofen to my 4-month-old."
Frequently asked questions
Does a higher temperature mean a more serious infection?
No. The child's age, appearance, behavior, and hydration guide the response more than the reading. Any fever in an infant under 3 months requires immediate evaluation.
Does the parent wake a sleeping child to give an antipyretic?
No. The goal of antipyretic therapy is comfort. A child who sleeps comfortably does not need a dose.
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