Dressing a baby with a fever: lighter, not warmer

The old instinct to bundle a sick child under thick blankets to sweat it out is wrong for babies, who overheat more easily than older children. Thick fleeces and hats trap body heat too, and push the temperature higher.

Stripping your baby completely bare backfires just as badly. Cold air on hot skin causes shivering. Shivering is the body's way of generating more heat, which drives the internal temperature back up and leaves your baby distressed.

Start with what your baby wears in that room on any other night, sleep bag included. Then slip your fingers onto the chest. If it feels hot or damp, take one thing away: short sleeves under the bag instead of long ones, or the next lighter bag.

Dress for the room, not for the top of the fever. A fever rises and falls through the night, and it drops once fever medicine starts working. A baby stripped down to the diaper at midnight can be cold by 3 AM.

When the fever breaks during the night, your baby may sweat heavily. Set out a dry change by the crib before you go to bed, so a soaked baby gets a quick change in the dark.

If your baby ends up in your bed tonight, as sick babies often do, your body warms your baby too. The sleep bag over a light bodysuit is plenty, with your own duvet kept at your waist.

Shivering usually means the fever is still climbing. The body is warming itself up to a higher temperature, so your baby shivers as if cold while the thermometer reading goes up. Once the fever stops rising, the shivering stops and your baby feels hot instead.

While the shivering lasts, lay a thin blanket over your baby in your arms. Warm clothes aren't needed, and they can make your baby overheat once the shivering ends. The blanket comes off as soon as the shivering stops, or when your baby falls asleep and goes into the crib in the sleep bag.

If the hands and feet feel unusually cold, or the skin looks pale, blue or blotchy, call your emergency number right away rather than reaching for socks.

A hand on the back of the neck or the chest tells you whether the clothes are right. It can't tell you whether your baby has a fever, or how high it is. Forehead kisses and palm checks are notoriously misleading, and more so while your baby is shivering.

Use a digital thermometer. The easiest place at home is under the arm, and it suits any child under 5. Tuck the tip high into the armpit, then hold your baby's arm gently against the side until it beeps. A rectal reading is the most accurate, which is why many pediatricians prefer it for young babies, especially under 3 months, and treat the armpit as a first check. If your baby has just come out of a warm sleep bag, a blanket or the bath, wait a few minutes before you measure, without letting your baby get cold.

Write the numbers down with the time, either on paper or in your phone. In the middle of the night, 38.4°C (101.1°F) at 1 AM blurs into 39.1°C (102.4°F) at 4 AM. A log helps you see whether the fever is responding to medicine, and it gives the doctor clear facts if you need to call.

A fever makes a baby lose fluid faster than usual, so for a sick baby, drinking enough matters more than bringing the temperature down. Keep offering regular breastfeeds or formula bottles. A baby with a fever might not want a full feed at once, so offer smaller amounts more often. From 6 months, sips of water count too.

Keep an eye on the wet diapers, too. Fewer than usual, a dry mouth or crying without tears all mean your baby needs more to drink. If your baby keeps refusing feeds or shows these signs, call your pediatrician for advice.

Once your baby is in a light layer and resting, the clothes are done. What matters now is how your baby looks and behaves, because a thermometer reading does not tell the whole story on its own. A baby who has a mild temperature but cannot be woken or struggles to breathe needs urgent care, while a baby with a higher fever who still makes eye contact and drinks milk is in a very different position.

Age changes the picture most. In a baby under 3 months, a temperature of 38°C (100.4°F) or higher needs a doctor straight away, however happy your baby seems.

Dress your baby for the weather outside, as on any trip, and take the hat and outer layers off as soon as you're inside. In the car seat, thin clothes go under the straps and a blanket goes on top, fever or not. An outfit that opens at the front, such as a sleepsuit with a zip, lets the doctor listen to the chest without pulling anything over your baby's head.