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What Is Heat Rash and How Can I Prevent It?

A long, bitter winter can have many of us longing for hot summer days. But as the weather heats up, so does the pain of dealing with the blistering heat and the potential for undesirable effects, such as heat rash.

Heat rash, also known as prickly heat or miliaria, is common in children, especially babies, and even adults. It’s most common in infants as their sweat ducts aren’t as developed. 

“Heat rash is caused by the blockage of ducts or pores of the sweat glands,” said Alyson Boone, a certified pediatric nurse practitioner with Banner Children's. “The sweat can become trapped underneath the skin and cause irritation, redness and a rash.”

Rashes are concerning when you have a little one, but it’s perfectly normal for them to get a heat rash from time to time.  

Read on to understand how to identify a heat rash, and most importantly, how to treat and prevent it when temps rise.

What does a heat rash look like?  

The signs of a heat rash are universal, whether you’re an adult or a child. You may notice mild to moderate red skin with tiny red bumps or small water blisters.

“Babies tend to develop this rash in the folds of the skin, like the neck, armpits, elbow creases and diaper area or on the face after breastfeeding,” Boone said. “In older children, it’s seen on the chest and back.”

While it’s not contagious, it can feel itchy or prickly like pins and needles. Symptoms of heat rash usually last no more than two to three days.

What causes heat rash?

Summer is the most common season for heat rash, and a humid climate can also contribute. But this skin condition can also occur in the winter months if your baby or child becomes overheated or warm from wearing too many layers of clothing. Sometimes oils and creams can block the sweat ducts.

In older children, a heat rash can develop during intense exercise or physical activity.  

“Heat rash is not usually accompanied by fever or other signs of an illness, like a cough or congestion,” Boone said.  

There are three types of heat rashes, ranging from mild to severe:

  • Miliaria crystallina is a mild type of rash that appears as clear or white blisters. 
  • Miliaria rubra appears as bumpy red spots that can bring on feelings of irritation and itchiness.
  • Miliaria profunda is a severe type of rash that looks like blisters that resemble pimples. They are typically skin-colored and can be painful.

How do you treat heat rash?

A heat rash typically gets better and goes away on its own, but there are some simple ways to take care of a heat rash. 

Boone shared the following tips for babies and children:

  • For smaller rashes: Apply a cool washcloth to the affected area for five to 10 minutes and then let the skin dry.
  • For larger rashes: Take a lukewarm/cool bath, soaking for five to 10 minutes and then allow the skin to air dry.
  • Clothing: Limit layering clothes on infants and ensure their room is cool enough while sleeping.
  • Hydration: Make sure everyone drinks plenty of fluids. 
  • Topical treatments: For older children, those older than 1 year of age, it is OK to try over-the-counter 1% hydrocortisone cream sparingly for itchiness if the rash is in a small area. Talk to your child’s provider before using this cream if your child is less than 12 months old. 
  • Avoid other creams and ointments: These can further block the pores of the sweat glands.

Call your child’s health care provider if the rash doesn’t improve after a few days, seems to get worse or if you notice signs of infection, such as fever, cough, congestion or drainage from the rash. 

“Additional symptoms such as drainage from the rash could be an indication of a secondary infection,” Boone said.

How do I prevent my child from getting a heat rash? 

The best way to prevent heat rash is to help your baby or child stay cool and dry, both indoors and out. 

Boone shared these tips to help prevent heat rash:

  • Use air conditioning or a fan to circulate the air and cool room temperatures on hot, humid days.
  • Keep your child properly hydrated.
  • Dress your child in light and breathable attire to keep their skin cool, preferably cotton clothing versus synthetic fabrics.
  • Change their diaper every two hours to avoid irritating their skin folds.
  • Avoid creams and lotions that can block the sweat ducts. 
  • Practice safe sleep practices. Don’t leave your little one asleep in a baby carrier, car seat or stroller.
  • Avoid outdoor activities during peak temperatures of the day.  


Heat rash is common in children, especially babies. It can sometimes be uncomfortable and irritating but usually will get better after a few days. 

With proper preventive measures, you can reduce your child’s risk of developing heat rash. But, in the off chance they do develop a rash, you’re armed with tips to bring your little one some relief. 

Need help diagnosing or treating heat rash?

Schedule an appointment with a pediatrician near you.

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