Call a pediatrician immediately
Seek emergency care now if the baby is under 3 months old and has a rectal temperature of 100.4°F (38°C) or higher
Use a rectal thermometer for the most accurate temperature
Remove extra clothing and blankets
Keep the baby in a comfortable room temperature
Offer breast milk or formula more often if the baby will feed
Do not give any fever medicine unless a doctor tells you to
Do not give aspirin
Do not use cold baths, ice baths, or alcohol rubs
Monitor for trouble breathing, poor feeding, unusual sleepiness, vomiting, rash, or fewer wet diapers
Get urgent medical help right away if the baby seems very ill or hard to wake