It's natural to be concerned when you see small red pustules on your baby's neck, chest, or back. These minor outbreaks are simply heat rash caused by sweat becoming trapped beneath the skin.
To relieve a mild heat rash, help your baby stay cool and dry and let their skin breathe.
Key Takeaways
- Sweat that gets trapped: lead to heat rash, which appears as small red spots in warm skin folds.
- To keep your baby cool, dress them in light clothes, keep the room cool, and give them a short bath with lukewarm water.
- Do not use heavy creams: thick ointments and oils are capable of trapping more heat.
- Most cases resolve rapidly: a mild heat rash generally gets better within two to three days.
What Is Baby Heat Rash? (A Explanation of Infant Miliaria)
Baby heat rash, which is known as miliaria, occurs when sweat is trapped beneath the skin and it usually appears as small red bumps or tiny clear spots, in the neck, on the chest, on the back, in the armpits and in other warm skin folds.
The Reason Why Babies Get Heat Rash So Easily
Since your baby's sweat glands are still growing and developing, it is far easier for theirs to become blocked than it is for adults'.
When your baby gets warm and begins to sweat, some of the moisture produced can become trapped underneath the skin.
A warm room, tight clothes, thick blankets, or even those sweet little baby skin folds can increase the chance of heat rash.
That’s why heat rash often improves once the trapped warmth is removed.
The different types of miliaria in babies: crystallina, rubra, and profunda
The appearance of heat rash can be slightly different according to the place where the sweat gets trapped.
- Miliaria crystallina consists of small, clear bumps which appear similar to little drops of water and usually cause no itching or pain.
- Prickly heat: The most common form of miliaria, appearing as small red pustules which may be itchy or uncomfortable.
- Miliaria profunda is a more severe form which is however much rarer and results in firm, skin-coloured pimples.
| Type | What It Looks Like | How It May Feel |
| Miliaria Crystallina | Tiny clear bumps | Usually no itching or pain |
| Miliaria Rubra | Small red bumps | Itchy, prickly, or uncomfortable |
| Miliaria Profunda | Firm, skin-colored bumps | Usually mild discomfort and uncommon in babies |
Common Triggers: The Reasons Why Babies Get Too Hot in the Summer and in the Winter
Baby heat rash can happen in any season whenever your baby gets too warm and sweaty.
The practice of over-bundling and excessive winter swaddling causes problems
It's very easy when it's winter to dress a baby too warmly, particularly if their hands and feet seem a bit cold. Yet the fact that their fingers are cool doesn't necessarily mean that your baby needs another blanket.
Try the back of the neck or the chest instead; if it is hot, sweaty, or damp, then your baby is probably overdressed.
A lot of close-fitting layers can cause heat to get trapped against your baby's skin. At bedtime, dress your baby in light and breathable pajamas and leave out the extra layers.
A simple rule is to dress your baby in one light layer more than the number of layers you are comfortably wearing.
The Nursery Environment, Humidity, and Hot Spots in the Car Seat
A stuffy and warm nursery may raise the chance of heat rash. It is helpful to keep the room at a comfortable temperature and to allow some air to circulate.
Car seats and baby carriers are also likely to be damp. Heat tends to accumulate around your baby in areas where fabric is in contact with their skin.
Following a warm car journey or after a sleep in the carrier, check your baby's neck and back; If their clothes feel damp, change them into something dry.
Sweating after the fever and heat by skin-to-skin contact
Babies can also sweat increased amounts as the fever decreases. If the pajamas or the bedding have become damp, then change them so that the moisture does not remain against the skin for a long time.
A soft, damp cloth can help if your baby is sweaty.
Long periods of skin-to-skin contact can also help to warm both you and your baby, particularly in a hot room. Skin-to-skin contact is still all right - you just need to be aware of sweating and move to a cooler place or take off a layer if your baby begins to feel hot.
Recognising heat rash on your baby's skin
Heat rash typically appears as small groups of bumps in the areas where your baby gets warm and sweaty; these bumps may be red or pink or, at times, look like tiny clear blisters.
With a baby who has darker skin, the redness may be more difficult to see. The bumps could appear skin-coloured, brown, greyish, or even a bit purple. It's a good idea to check them in natural light to make it easier to spot them.
What Heat Rash Looks and Feels Like
The most common form, known as prickly heat, typically appears as a number of small raised bumps that are near one another. When your baby gets warm they may feel a bit itchy, be fussy, or simply be uncomfortable.
There is another kind which appears as small, transparent drops on the skin and generally causes little or no trouble for your baby at all.
When you gently slide a clean fingertip over the area, heat rash usually makes the surface feel a bit rough or bumpy rather than completely smooth.
Heat rash itself should not cause a fever. If your baby has a fever or seems unwell, contact your pediatrician.
The areas where heat rash commonly occurs
You will usually find heat rash where warmth and moisture get trapped:
- Around the neck folds
- Across the chest and back
- Under the arms
- Around diaper edges
- Behind the knees or inside the elbows
- Under snug clothing or straps
The neck is a really common spot for heat rash, since sweat, drool, and even milk can collect in those little folds. The back can get sweaty too, especially during naps, car rides, or when your baby is in a carrier.
If you’re seeing bumps mostly in these warm, covered areas and your baby seems fine otherwise, it's most likely just heat rash.
Rapid At-Home Cooling Protocol and Soothing Skin Care
When baby heat rash shows up, the first step is simply helping your baby cool down. You usually do not need a complicated routine. A cooler room, fewer layers, and gentle skin care are often enough for mild cases.
Try these simple steps:
- Keep the room cool: Keep the nursery comfortably cool and avoid stuffy, overheated spaces.
- Remove extra layers and loosen anything tight around the rash.
- Give your baby a short bath to rinse away sweat.
- Dry gently: Pat your baby’s skin dry and let those warm folds air out for a bit.
Keep Baths Short and Lukewarm
Stick with comfortably lukewarm water, not too hot or cold. A quick 5- to 10-minute bath is usually enough to cool your baby’s skin and rinse away sweat.
If your baby's skin is suffering from an active heat rash, then make your baths as simple as possible and avoid using bubble baths and strong-scented washes, particularly since the skin is already appearing irritated.
For most babies, plain water is enough.
Pat Dry Instead of Rubbing
Since heat rash can cause your baby's skin to feel more sensitive, it's best not to rub it with a rough towel.
Gently pat your baby dry with a soft towel, especially around the neck, armpits, and those little skin folds. If the room is warm enough, you can even leave clothes or the diaper off for a few minutes so those spots can air out naturally.
Be Careful With Heavy Ointments and Creams
It’s tempting to grab a thick cream when you see a rash, but heat rash isn’t the same as dry skin or eczema. Heavy ointments, oils, and petroleum-based products can actually trap more heat and moisture against your baby’s skin.
If you are unsure what's safe to use, our guide to evaluating safe heat rash cream for babies explains which products may be more suitable during a flare.
Skip adult anti-itch creams or hydrocortisone unless your pediatrician says it’s okay. For most mild cases, cooling is the best place to start.
Safe Sleep and Breathable Sleepwear Selection
Babies can get warm really fast during sleep, especially if pajamas, swaddles, and blankets start to pile up. If your baby already has heat rash, keeping bedtime layers simple can help stop more sweat from building up on their skin.
The goal is simply to keep your baby comfortably cool without piling on extra layers.
Keeping the Nursery Comfortably Cool
A room that’s around 68°F to 72°F (20°C to 22°C) is comfy for most babies, but the best way to check is to feel how your baby actually feels.
Touch the chest or back of the neck. If the skin feels hot or sweaty, remove a layer. The American Academy of Pediatrics also recommends dressing babies in no more than about one extra layer compared with what an adult would comfortably wear in the same room.
A fan can help keep the air moving in a warm nursery, but it doesn’t need to blow right on your baby.
At bedtime, keep your baby’s head uncovered. Skip hats and hooded outfits indoors, and don’t use loose blankets in the crib.
Understanding the TOG ratings and sleep layers
A TOG value indicates how warm a sleep sack or wearable blanket is; the lower the TOG, the lighter it is, and the higher the TOG, the more insulation it provides.
Use the manufacturer's temperature guide as a starting point:
| Nursery Temperature | Typical TOG | Possible Base Layer |
| 74°F–78°F (23°C–26°C) | 0.5 TOG | Diaper or short-sleeve bodysuit |
| 69°F–73°F (21°C–23°C) | 1.0 TOG | Short- or long-sleeve bodysuit |
| 61°F–68°F (16°C–20°C) | 2.5 TOG | Warmer pajamas or footed sleeper |
These ranges can vary by brand, so always check the care guide that comes with your baby’s sleep sack.
During an active heat rash flare, lighter layers may feel more comfortable.
And skip loose blankets in the crib. A well-fitted sleep sack can keep your baby warm without adding extra bedding.
Choosing Breathable Sleepwear for Heat Rash
When your baby’s skin is already warm and bumpy, soft, lightweight pajamas can make bedtime easier. Choose sleepwear that is breathable and fits well without rubbing on irritated areas.
For daytime, breathable bamboo baby bodysuits are a soft choice when you want lightweight coverage.
Bamboo viscose is soft and lightweight, but fabric alone won’t prevent heat rash. Room temperature, the number of layers, and whether your baby is sweating still matter most.
How to Distinguish Heat Rash from Other Common Infant Rashes
Baby rashes can all look pretty similar at first. The easiest clues are usually where the rash shows up, how the skin feels, and whether your baby seems well otherwise.
| Condition | Where It Often Appears | What It Looks Like | Common Clue | Typical Care |
| Heat Rash (Miliaria) | Neck, chest, back, skin folds | Tiny red or clear bumps | Warmth and sweating | Cool the skin, lighter layers |
| Baby Acne | Cheeks, forehead, nose | Small pimples or whiteheads | Common in young newborns | Gentle cleansing, patience |
| Infantile Eczema | Cheeks, arms, legs | Dry, rough, scaly patches | Dry, itchy skin | Regular moisturizing |
| Drool Rash | Chin, mouth, neck | Red, irritated patches | Saliva sitting on the skin | Keep dry, use a gentle barrier |
| Allergic Hives | Can appear anywhere | Raised, smooth welts | Spots may move or change quickly | Medical advice if needed |
The table may help you to identify patterns, but it doesn't serve as a diagnosis; so if the rash appears unusual or your baby seems unwell, it's best to consult your pediatrician before attempting anything new.
Heat rash as compared with baby acne
Baby acne typically appears on the face, particularly on the cheeks, the forehead, and the nose. The bumps can look similar to small pimples or tiny whiteheads.
Heat rash, on the other hand, usually pops up in warm, sweaty areas like the neck, chest, back, or those little skin folds. When you’re trying to tell the difference between baby acne and heat rash, location is one of the easiest clues. Heat rash can also feel a little rough and often gets more noticeable after your baby gets warm.
Heat Rash vs Eczema and Drool Rash
Eczema tends to be both drier in appearance and in feel than heat rash and may show up as rough, flaky, or scaly patches, typically found on the baby's cheeks, arms, or legs.
That matters because eczema often needs regular moisturizing, while heat rash usually needs a cooler, drier environment.
When you’re comparing heat rash and eczema, focus on texture. Heat rash usually shows up as small bumps that look like weepy spots. Eczema looks more like dry patches that keep coming back.
Drool rash is another common one, especially when your baby is teething. It usually shows up around the mouth, chin, cheeks, or neck—anywhere saliva keeps the skin damp.
To tell the difference between drool rash and heat rash, check what is in contact with your baby's skin. If the irritation is mainly in the areas where drool gathers, then saliva is most likely the cause.
A gentle barrier balm can help with drool rash, but heat rash usually needs a different approach.
Heat Rash vs Allergic Hives
Hives typically differ from the small, clustered bumps associated with heat rash since they are generally larger and appear as raised patches that can suddenly show up and then alter either their shape or position over time.
Heat rash remains in warm or covered areas until the skin cools off, and hives can show up all over the body, including areas that are not sweating.
When you’re trying to tell heat rash from an allergic reaction, pay attention to how quickly the rash changes and how your baby is acting overall.
If your baby has hives along with swollen lips or tongue, or seems unusually drowsy, seek urgent medical help immediately, since those are not symptoms of a simple heat rash.
Pediatric Red Flags: When Heat Rash Requires Medical Attention
A mild heat rash usually improves after a few days; however, if the rash worsens, it's best to have your pediatrician take a look.
Be on the lookout for changes such as swelling, oozing, crusting, or bumps that begin to appear filled with pus.
Signs the Skin May Be Infected
Heat rash is generally not dangerous, but it can become infected at times if the skin is scratched or irritated.
Call your pediatrician if you notice:
- White or yellow pus-filled bumps
- Oozing or honey-colored crusts
- Increasing redness or swelling
- Skin that feels unusually warm or painful
- Redness that keeps spreading beyond the original rash
Honey-colored crusting can be a sign of impetigo, and spreading warmth or swelling might mean another skin infection. These symptoms need a doctor’s evaluation, not just home cooling care.
Try not to scratch, squeeze, or pop the bumps, even if they look irritated.
Fever and Other Warning Signs
Heat rash itself should not make your baby sick or cause a fever. If your baby has other symptoms along with the rash, something else may be going on.
Contact a healthcare professional if:
- Your baby has a fever: A rectal temperature of 100.4°F (38°C) or higher in a baby under 3 months needs prompt medical attention.
- The rash isn’t getting better: Have it checked if it keeps getting worse or hasn’t started to improve after a few days of cooling care.
- Your baby is unusually sleepy or feeding poorly: If your baby is hard to wake, floppy, or refusing feeds, seek medical attention.
- The skin looks infected: Watch for pus, crusting, swelling, spreading redness, or increasing tenderness.
Get urgent medical help if your baby has trouble breathing, blue or gray lips, is hard to wake, or develops purple or red spots that don’t fade when you press on them.
You know your baby best. If something about the rash or your baby’s behavior just doesn’t feel right, it’s always okay to call your pediatrician. To keep your baby's sleep space comfortable and safe, explore the SWaddle AN safety focus blog library.
