Babies, like adults and children, sweat to help cool the body. Reasons a baby may sweat can include overheating, crying, fever, genetic differences, and certain medical conditions.

Parents and caregivers should view sweating as a sign that the baby is too hot and may need help to cool down.

When sweating is excessive or happens even when the baby is not hot, it may signal a medical condition. When babies overheat, their risk of sudden infant death syndrome (SIDS), heat-related illness, and other health issues increases.

Doctors call excessive sweating hyperhidrosis.

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Several different factors can cause a baby to sweat.

Overheating

Sweating is the body’s natural response to becoming too hot. Babies who get too hot may be overheating, which causes them to sweat.

They may sweat all over the body or only in certain areas, such as the head.

Sometimes, the area that sweats the most is the hottest. For example, a baby may sweat on their head if they are wearing a hat in the sun.

Overheating in babies can be dangerous because babies are less able to regulate their body temperature than adults.

Also, as sweating cools the body, it may make a baby too cold. Therefore, it is important for parents and caregivers to dress babies in cool layers and try to prevent overheating.

Crying

Crying can make a baby feel hot, causing them to sweat. This effect is more common when a baby cries very hard or for a long period.

Some research suggests that babies may sweat on their palms and feet when they are upset. Parents and caregivers may notice this sweating even after a baby stops crying.

Fever

Babies may sweat when they have a fever or when the fever breaks. Fever may indicate that the baby has an infection. Although a fever itself is not usually dangerous, the infection may be.

Fever medication may make the fever go away, but it will not treat the infection. Therefore, people should not assume that the baby is better just because medication successfully relieves sweating or a fever.

Idiopathic hyperhidrosis

Idiopathic describes a medical condition or symptom for which there is no known cause.

Idiopathic hyperhidrosis is excessive sweating without an underlying medical condition or other clear cause.

Most babies with this condition have the same number and size of sweat glands as people who do not sweat excessively. However, the sweat glands are more active, possibly due to the increased activity of part of the nervous system.

Palmar hyperhidrosis is a type of excessive sweating that affects the palms of the hands. It is relatively common in infants and not dangerous.

However, some adults with this condition may choose to have surgery to weaken some nerve pathways to the sweat glands, especially if the sweating makes them anxious or makes it difficult to hold objects.

Sleep apnea

Sleep apnea is when a person stops breathing during sleep. It is more common among premature babies and occurs when the baby stops breathing for more than 20 seconds.

There may be a link between sleep apnea and SIDS, although the research on this is not conclusive.

An older study from 2008 suggests that sleep apnea occurs more often when babies are hot. The sleep apnea does not cause the overheating, but overheating may cause sleep apnea.

Parents or caregivers who notice that their baby is very hot or sweaty when they wake up may need to remove some clothing or put the baby in a cooler room overnight and for naps.

Medical conditions

A wide range of medical conditions can cause babies to sweat more than usual.

In most cases, the baby will have other symptoms. However, sweating is sometimes the earliest indicator. Some conditions that may cause excessive sweating include:

  • heart disease, including heart defects
  • cancer
  • endocrine system disorders
  • glucose control disorders, such as diabetes
  • lung disease
  • infections

Birth abnormalities and genetic differences

Numerous genetic disorders can cause babies to sweat more than usual.

For example, cold-induced sweating syndrome makes it more difficult for children to regulate body temperature.

Babies with this condition may sweat when cold. They also typically have weak facial muscles, a flat bridge of the nose, and certain health problems, such as high fevers and, sometimes, seizures.

Some other genetic disorders, such as Apert syndrome, may also cause excessive sweating. In most cases, a child has many other symptoms in addition.

For instance, Apert syndrome causes fused fingers and toes, abnormal development of the face and skull, and, in some cases, heart problems.

Several treatments may help with excessive sweating.

However, in babies who experience prolonged excess sweating, not just a single incident during which they sweat a lot, it is important to diagnose and treat the underlying cause. It may be a serious medical condition.

When babies seem unusually hot, parents and caregivers can help by:

  • breastfeeding the baby or giving them a bottle to help prevent dehydration
  • removing a layer of clothing
  • moving the baby to a cooler area, such as an air conditioned room
  • paying attention to the circumstances in which the baby sweats to try to identify causative factors, such as the sun shining directly into their crib

However, it is important to avoid doing anything that might make the baby cold, such as putting them directly in front of an air conditioner.

Parents or caregivers should seek medical help for a baby who:

  • is a newborn and develops a fever
  • has signs of an infection, such as a fever or pain, that do not go away within a day or two
  • sweats a lot even in comfortable temperatures, with the symptoms persisting for several days
  • seems unusually sweaty on certain areas of the body, even in comfortable temperatures
  • has frequent episodes of sleep apnea
  • has a reduced urine output, which could be a sign of dehydration
  • sweats during feeding, which may indicate a heart condition

Sweating is normal and healthy in people of all ages, including babies.

However, excessive sweating may mean that the baby’s environment is not comfortable. In some cases, it may indicate a serious underlying medical condition.

Parents and caregivers should always err on the side of caution and discuss any unusual symptoms with a doctor.