If your toddler is on the move or it’s just hot where you are, they’re bound to sweat. This means there’s a chance of getting a heat rash, especially in warmer weather.

Kids and babies already tend to have warmer body temperatures than adults do. Add crawling, cruising, running, climbing to that, too, since the Centers for Disease Control and Prevention (CDC) recommends that young children get 60 minutes of moderately intense activity every day if possible.

So, if you notice a skin rash when you unbundle your toddler, it could be a heat rash, known as miliaria. Below are things you can do and look out for.

Heat rash happens when sweat ducts in the skin are blocked and sweat gets trapped, creating fluid-filled bumps on the skin. In most cases, the bumps show up where there’s friction: One body part rubs against another or tight-fitting clothes rub against the skin.

The most commonly affected zones on children’s bodies are:

  • neck folds
  • elbow and knee creases
  • armpits
  • inner thighs

Did your baby wake up with a rash?

Heat rash can sometimes happen while children are sleeping. If pajamas are bulky, blankets are too heavy, or the fabric doesn’t breathe, they could be trapping heat and perspiration. Try these tips:

  • use a light blanket
  • layer blankets
  • opt for breathable cotton sleepwear

If temperatures drop and your toddler’s room becomes too cool for comfortable sleeping, it’s better to layer light blankets so you can remove one when the room warms back up.

Most of the time, heat rash starts clearing up on its own as soon as you cool off your toddler. Several at-home treatments you can provide to start healing the rash include:

Cool the skin

You can do this by removing extra layers of clothing or by moving to a cooled indoor space. If your toddler’s been outside in heat and humidity, remove damp clothing and turn on a fan to dry your child’s skin.

Apply water

  • For small rash patches. If the affected area is relatively small — just a patch on the back of the neck or in the creases of the elbows — gently dab a cool, wet cloth on the rash to relieve tenderness and bring down the skin temperature.
  • For larger rash areas. You can also give your toddler a cool bath for at least 10 minutes, but don’t use soap because it could further irritate the skin. Afterward, let your toddler’s skin air-dry.

Try a steroid cream

It’s important to keep kids from scratching if the rash is itchy, because broken blisters can lead to skin infection. If your toddler lets you know the rash is bothersome, you can smooth some over-the-counter 1 percent hydrocortisone cream onto the bumpy area.

Avoid hydrocortisone ointments that contain petroleum or mineral oil since they can block pores and keep sweat from evaporating naturally.

Use calamine lotion or anhydrous lanolin

Calamine lotion can help stop any itching if your child has a more severe type of heat rash. They also recommend anhydrous lanolin — the kind found in nipple treatments for breastfeeding mothers — to keep sweat ducts clear and open.

Rash hasn’t gone away or gets worse

Heat rash usually clears up on its own within a week. If your toddler’s skin hasn’t cleared up by then, or if the rash gets worse or looks infected, it may be time to talk to your pediatrician.

If your child has a fever

As with any rash, if your child develops a fever when the rash appears, it’s a good idea to check with your doctor. The doctor could prescribe a different steroid cream or could advise you on using antihistamines to treat the problem.


When you’re at the park or on the playground, check to be sure your child isn’t getting overheated during playtime. If you notice damp clothes or flushed skin, remove a layer of clothes or move to a shady or air-conditioned space for a while.


Whether you’re playing in cold or warm temperatures, make sure to take frequent water breaks. When your toddler is hydrated, body temperatures are more likely to stay at healthy levels.

Dress in layers

If you’re headed out to play in cold weather, dress your toddler in clothes made of breathable, moisture-wicking fabric that allows sweat to evaporate from the surface of the skin.

Be cautious about adding too many layers because when kids romp vigorously, layers can trap body heat and sweat. The best practice is to dress your child about as warmly as you would be in the same temperatures.

Look for breathable sleepwear

Some pajamas for children are made of polyester fabrics with fire retardants in the fibers.

In a case report from 2011 that looked at 18 people wearing fire retardant uniforms working in hot conditions, miliaria ruba was one of the reactions to wearing the fire retardant clothing.

Some pediatricians are concerned about other possible health risks flame retardants may pose to children, so cotton might give you the most peace of mind.

Cotton is a natural fiber that allows your child’s body to release heat and sweat. The Consumer Product Safety Commission recommends that your toddler’s pajamas fit close to the skin and not too loosely.

Re-rinse laundry

Detergent or residue from laundering may stay in fabrics and cause skin irritation or contribute to heat rashes. Adjusting your laundry routine a little might help reduce how often heat rashes happen. Try adding an additional rinse cycle or adjusting your detergent levels.

It depends on what type of heat rash it is. Here are a few subtypes of heat rash and their signs.

Miliaria crystallina

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Miliaria crystallina on a newborn

Miliaria crystallina affects the top layer of skin, called the epidermis, and can cause blister like lesions. If your baby has a rash, you should consider putting mittens on his or her hands to prevent scratching and open wounds.

Miliaria crystallina is the mildest type of heat rash. You might see small, clear, blister-like bumps on the surface of your toddler’s skin. The bumps aren’t painful and they don’t usually itch, but the tiny blisters can sometimes break open if they’re scratched.

Miliaria rubra

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Miliaria rubra on a baby

Miliaria rubra affects the second layer of the skin called the dermis, and can cause itchy or painful sensations.

Miliaria rubra may be more common for adults but children are affected, too. This red, bumpy rash affects the epidermis, a deeper layer of the outer skin. It’s sometimes called prickly heat because the bumps on the skin can be tender, and they can sting or itch.

This rash can cause discomfort and toddlers may be irritable while it’s healing.

Miliaria profunda

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Miliaria profunda

Miliaria profunda affects the deepest layer of skin and is very rare in infants. Since it’s so deep, the rash tends to be skin-colored. Although it may look milder, the effects can be more serious.

Miliaria profunda is rare among babies and toddlers. It affects the dermis, an even deeper layer of the skin. The bumps are skin-colored, not clear or red, and they’re usually much bigger and tougher than the bumps from other types of heat rash.

Miliaria profunda occurs when sweat leaks out of your glands, forming fluid-filled pockets under the skin.

Heat rash is a skin condition that comes from blocked sweat ducts. The bumps could be clear, red, or skin-colored, depending on how severe the rash is. The bumps might be sore or itchy.

Most of the time, the rash will go away on its own as soon as you cool off your toddler’s skin. You can also treat it with cool water, hydrocortisone cream, or calamine lotion.

If the rash doesn’t clear up in a few days, talk to your doctor to be sure your toddler’s skin hasn’t become infected. The doctor may prescribe other creams or antihistamines to help with recovery.