Fever Management

What counts as a fever?

A fever is generally defined as a body temperature of 100.4°F (38°C) or higher. The most accurate readings in young children come from rectal thermometers (under 3 months), temporal artery (forehead) scanners, or oral thermometers in cooperative older children. Axillary (armpit) readings tend to run about 1°F lower than core temperature and are less reliable.

Fever itself is a normal immune response — the elevated body temperature helps the immune system fight infection. Studies have not shown that suppressing a fever shortens illness or prevents complications. Treat the child's discomfort, not the number on the thermometer.

When to call the doctor

Age-based fever thresholds:

• Under 3 months: Any fever ≥100.4°F (38°C) — seek care immediately. Infants this young can't always show signs of serious infection, and routine fever workup is standard.
• 3–6 months: Fever ≥102°F (38.9°C) — call your doctor the same day.
• 6–24 months: Fever ≥102°F (38.9°C) lasting more than 24 hours — call your doctor.
• 2 years and older: Fever ≥104°F (40°C), or any fever lasting more than 3 days — call your doctor.

Always call your doctor if:

• Your child appears unusually irritable, lethargic, or hard to console.
• Fever returns after being gone for more than 24 hours.
• Your child has a chronic medical condition (heart disease, sickle cell disease, immune deficiency, oncology history).
• Fever is accompanied by a new rash, severe headache, ear pain, painful urination, or refusal to drink fluids.

Alternating acetaminophen and ibuprofen

When fever-related discomfort isn't controlled by a single medication, your pediatrician may approve alternating acetaminophen (Tylenol) and ibuprofen (Advil, Motrin). The two medicines work by different mechanisms, so they can be safely staggered.

Important safety notes:

• Ibuprofen should not be given to infants under 6 months due to kidney maturity concerns.
• Always use weight-based dosing — see our OTC dosage calculator.
• Each individual medication has its own dosing interval (acetaminophen every 4–6 hours, ibuprofen every 6–8 hours). Alternating creates a 3-hour gap between any dose, but each medicine still has its own ceiling.
• Write down what you give and when. Mistakes happen most often when more than one caregiver is involved.

Sample alternating schedule:

Alternate every 3 hours. Acetaminophen is given every 6 hours; ibuprofen every 6 hours. Always use the correct dose for your child's weight, and discontinue alternating once symptoms improve.

Comfort measures (without medication)

Many children with mild fevers (under 102°F) don't need medication at all. The following measures support comfort and natural recovery:

• Fluids: Offer water, diluted juice, ice pops, or an electrolyte solution like Pedialyte. Fevers increase fluid losses through breathing and sweating.
• Light clothing: Dress in a single layer. Over-bundling traps heat and worsens fever.
• Lukewarm bath or sponge bath: Use water around 85–90°F. Cold water and ice baths cause shivering, which actually raises body temperature.
• Rest: Encourage quiet activities; don't force sleep. Children often sleep more during fevers naturally.
• Cool compress: A damp washcloth on the forehead, neck, or wrists is comforting.
• Room temperature: Keep the room comfortably cool — around 68–72°F.

Avoid:

• Cold baths or ice baths — they cause shivering and raise core temperature.
• Alcohol rubs — dangerous and can be absorbed through skin or inhaled.
• Heavy blankets or excess clothing.
• Aspirin in any child or teen with a viral illness — risk of Reye's syndrome.

Warning signs — seek emergency care

Go to the emergency room or call 911 if your child has a fever and any of the following:

• Difficulty breathing, fast breathing, or visible chest retractions
• Blue or grey lips, tongue, or nailbeds
• Severe headache, stiff neck, or sensitivity to light
• Unusual rash, especially purple/red spots that don't fade when pressed (the "glass test")
• Persistent vomiting or inability to keep fluids down for more than a few hours
• Seizure or convulsion
• Extreme lethargy — difficult to wake, limp, or not responding to you normally
• Bulging soft spot (fontanelle) on an infant's head
• Signs of dehydration: no tears when crying, dry mouth, sunken eyes, no wet diapers for 8+ hours
• Any fever in an infant under 3 months

Trust your instincts. You know your child better than anyone — if something seems wrong, even without a textbook symptom on this list, call your pediatrician or seek care.