Your baby’s skin can feel incredibly delicate, so it’s easy to worry when a rash suddenly appears. One common skin condition many babies experience is heat rash, also called prickly heat or sweat rash. While it can look uncomfortable, baby heat rash is usually mild and improves quickly with simple cooling measures.
Understanding what causes baby heat rash, how to recognize it, and the best ways to soothe and prevent it can help you feel more confident caring for your baby’s skin. Here’s what parents should know about the symptoms, treatment options, and when to contact a pediatrician.
Key Takeaways
- Baby heat rash happens when sweat ducts become blocked and trap sweat under the skin
- Heat rash often appears as small red bumps or blisters in warm, sweaty areas of the body
- Keeping your baby cool and dry is the best way to treat and prevent heat rash
- Most mild cases improve within hours to a few days
- Contact your pediatrician if the rash worsens, spreads, or is accompanied by fever or signs of infection
What Is Baby Heat Rash?
Baby heat rash (also called miliaria, prickly heat, or sweat rash) is a skin condition that occurs when the eccrine glands and their ducts, which make and release sweat, become blocked.1 This blockage can lead to small red bumps, blisters, or pink irritated skin that may feel itchy or uncomfortable.
These symptoms commonly appear in areas where sweat accumulates, such as the groin, neck, arms, chest, and upper back.1,2 Heat rash rarely affects the baby’s face.1
Heat rash is especially common in newborns and young infants because their sweat glands are still developing.
What Causes Heat Rash in Babies?
When babies’ bodies heat up and sweat, their sweat ducts can get clogged.2 Babies have delicate skin and a less efficient sweating system than adults, making them more susceptible to conditions that cause sweating and overheating.3 Some common causes of baby heat rash include:
- Hot and humid conditions: Weather that causes sweating can contribute to baby heat rash.1,2
- Fever: Just like warm weather can heat up a baby’s body and cause them to sweat, so can a fever.9
- Ointment: Babies can also get heat rash in the winter if the creams or ointments applied to their skin clog ducts and trap sweat. Lanolin ointment applied to the mother’s nipples for breastfeeding can also cause baby heat rash if it transfers to the baby’s face and blocks their pores.2 This could be mistaken for a teething rash, a similar condition caused by drool irritation rather than sweat.4
- Tight clothing: Clothes that are tight or rub against the skin can obstruct sweat ducts.1,2
- Exercise: Heat rash can also appear in a toddler or an older child due to sweating.2
Types of Baby Heat Rash
There are three types of heat rash, each varying in severity and appearance. Heat rash can appear differently depending on how deeply the sweat ducts are blocked within the skin.1
1. Miliaria Crystallina
Miliaria crystallina is the mildest and most superficial form of heat rash, presenting as tiny, clear, fluid-filled blisters resembling water droplets that break easily. It generally doesn’t cause discomfort and resolves quickly with cooling measures.1
2. Miliaria Rubra
This is the most common type of heat rash in babies. Miliaria rubra involves a deeper blockage of the sweat ducts. Sweat becomes trapped deeper in the skin, triggering an inflammatory response that often appears as redness. Inflammation causes the classic heat rash symptoms, including red, itchy bumps and discomfort that may worsen with increased sweating.1
3. Miliaria Profunda
This is a rarer form of heat rash that occurs deeper in the skin layers. It typically happens after numerous repeated episodes of miliaria rubra and in extremely hot environments, so it’s less common in babies than in adults. Miliaria profunda presents as larger, flesh-colored bumps or cysts that can be extremely itchy or asymptomatic.1
Related: Understanding Baby Acne and How To Treat It
How Long Does Heat Rash Last?
The duration of heat rash varies depending on the type, severity, and treatment steps. In most mild cases, heat rash can resolve on its own within a few hours to a couple of days once the baby is moved to a cooler environment and their sweat glands are no longer blocked.1 However, if the rash persists or worsens despite treatment, your baby develops a fever without a known cause, or the rash spreads or has pus to indicate infection, you should contact your child’s pediatrician.2
How To Treat Baby Heat Rash
Remember, heat rash typically resolves on its own.1 To speed up recovery, effective heat rash treatment focuses on relieving the symptoms and preventing further sweating. Here are some methods to consider:
Cool the Skin
The simplest home remedies for heat rash involve lowering your baby’s temperature. Move your baby to a cooler, less humid environment. Dress them in lightweight, breathable clothing and keep them in a well-ventilated room. You can try a cool washcloth or a lukewarm bath without soap to cool them down, but don’t let them soak in the cold for more than 10 minutes.2
You can also use a fan to cool them down, supervising them to ensure their fingers stay away from the fan blades.
Treat the Fever
When your baby has a known cause of fever, such as a cold or other viral illness, treating the fever can lower their body temperature and thus help treat the heat rash. Tylenol (acetaminophen) and Motrin (ibuprofen) are the most common medications used to treat fever.10 If you’re unsure which one or how much to use, contact your pediatrician’s office for guidance. Also, reach out if you’re unsure of the cause of the fever and/or rash.
Related: Fever in Babies: A Parent’s Guide and Treatment Tips
Use Heat Rash Cream
Over-the-counter creams specifically designed for heat rash can help soothe the affected area. However, many of these creams aren’t meant for small infants, so consult your pediatrician before applying them. Here are some ingredients to look for in a heat rash cream for your baby:
- Aloe vera: This can cleanse, cool, moisturize, and disinfect the skin, but be sure not to apply too much, as it can clog sweat ducts.5
- Calamine: Calamine lotion may also be helpful for heat rash, but again, ensure it’s safe for your baby’s age.2
- Hydrocortisone: For more severe cases of baby heat rash, a mild steroid cream, such as hydrocortisone cream for baby or triamcinolone (prescription), can help reduce inflammation and itching. Be sure to use a cream, not an ointment, which could further block the sweat ducts.1,2
Related: 5 Toxins To Avoid in Baby Skin Care Products
How To Prevent Baby Heat Rash
Similar to treatment, preventing heat rash mainly involves keeping your baby cool, dry, and comfortable during warm conditions. Here are some practical tips on how to prevent heat rash:
1. Dress Them Lightly
Choose lightweight, breathable fabrics such as cotton for your baby’s clothing. Cotton and other natural fabrics absorb moisture, keeping the skin cool and dry.6 Don’t dress them in anything too tight, and stick to light-colored clothing that won’t trap heat against your baby’s body.7 Avoid overdressing your baby during sleep, especially in warm rooms. Breathable sleepwear and sleep sacks can also help reduce overheating at night.
2. Make Sure They Stay Hydrated
Ensure your baby drinks plenty of fluids to stay hydrated. Proper hydration can help regulate their body temperature and reduce sweating. Babies under 6 months old should only have breastmilk or formula to stay hydrated, but they may need more milk than usual in hot conditions.7
3. Use Air Conditioning
Maintain a cool environment wherever possible. If air conditioning isn’t available, use fans and keep the room well-ventilated.6 Also, be sure to cool the car — my babies always sweat so much in the car in the summer because the air conditioning doesn’t reach them right away. If possible, start your car and run your air conditioning for a minute or two before strapping them into the hot car seat.
Just remember: Never leave a baby alone in a parked car, even if it feels cool outside!7
4. Avoid Direct Sun Exposure
Keep your baby out of direct sunlight (particularly during the hottest parts of the day) to prevent overheating. It’s best to keep them in the shade or use UV-protecting hats and clothes whenever possible.2 If they must be in the sun, use a lightweight mineral baby sunscreen that won’t clog their pores.8
5. Avoid Ointments and Powders
Ointments and other greasy and thick skin products, such as those used to treat another skin condition called eczema, can clog sweat glands and make heat rash worse.2 It was once thought that baby powder would absorb moisture, but it doesn’t prevent heat rash. It can actually clog pores and trap heat, contributing to heat rash in babies.6
Related: What Is Baby Eczema and How to Treat Your Baby’s Skin
6. Give Your Baby Frequent Baths
Give your baby lukewarm baths to help cool their skin and remove sweat when they’re overheated. Avoid harsh soaps or bubble baths, as they can irritate the skin further. While exfoliating isn’t recommended for baby skin, gently rinsing and cleansing your baby frequently can help prevent the buildup of sweat and skin residue that clogs sweat ducts and causes heat rash.2
Baby heat rash is common, especially during warm weather or when babies become overheated. While the rash can look uncomfortable, it is usually mild and improves quickly with cooling and gentle skin care. Paying attention to your baby’s temperature, clothing, and environment can help prevent future flare-ups and keep your baby comfortable year-round.
Related: How Often Should Babies Take a Bath?
