Fever: when to call

A fever is usually the body fighting an infection, and most are not dangerous. In young babies, though, a fever needs a call to the doctor right away, and some signs mean getting help urgently at any age. This guide covers those thresholds and red flags. It doesn't cover treatment: ask your pediatrician before giving any fever medicine, and for the right amount for your baby.

Taking a temperature

• A temperature of 38°C (100.4°F) or more is a fever (AAP, NHS).
• For babies under 3 months, a rectal reading is the most accurate (AAP).
• Ear thermometers aren't reliable under 6 months, forehead (temporal artery) thermometers can be used at any age, and armpit readings are the least accurate (AAP).
• Log the reading in Chickpea, with the method, so everyone caring for your baby sees it.

The thresholds below go by age since birth. If your baby was born early, ask your pediatrician which to use.

Call your pediatrician right away

• Under 3 months with a temperature of 38°C (100.4°F) or more, even if your baby seems otherwise well (AAP). Call right away. If you can't reach your pediatrician quickly, go to the emergency department. Babies this young with a fever need to be checked by a doctor (AAP, Pantell 2021). The NHS gives the same threshold for urgent help.
• 3 to 6 months with a temperature of 39°C (102.2°F) or more (NHS). NICE's guidance for clinicians uses the same thresholds.
• A temperature that rises above 40°C (104°F) repeatedly, at any age (AAP).
• A fever lasting more than 24 hours in a child under 2 (AAP). The NHS says to get advice for a high temperature lasting 5 days or more.
• A fever with a rash, repeated vomiting or diarrhea, or signs of dehydration: fewer pee diapers, a dry mouth, fewer tears than usual, or a sunken soft spot (AAP, NHS).
• Your baby isn't feeding, isn't their usual self, or you're worried. Trust that feeling.

Call emergency services now

From the NHS, for a baby or child who:

• has blue, grey, pale or blotchy skin, lips or tongue
• is struggling to breathe, or breathing very fast
• is very drowsy or hard to wake, or is not responding as usual
• is extremely agitated and won't stop crying, or seems confused
• has a stiff neck, or seems bothered by light
• has a rash that doesn't fade when you press a glass against it
• has a seizure (fit) for the first time
• has unusually cold hands and feet
• has a very low temperature, under 36°C (96.8°F), or feels cold to the touch or is shivery (NHS page on sepsis, for babies and children under 5).

Chickpea never diagnoses. It keeps a record of temperatures so everyone caring for your baby, and your pediatrician, can see them.