My Baby Has Heat Rash
The short answer
Heat rash (miliaria) is very common in babies and occurs when sweat ducts become blocked, trapping perspiration beneath the skin. It appears as small red or clear bumps, often in skin folds, on the neck, chest, groin, or diaper area. Heat rash is not dangerous and typically resolves on its own within a few days once the baby is cooled down. The best treatment is cooling the skin, dressing your baby in loose clothing, and avoiding overheating.
Parents everywhere have the same worry. You are doing the right thing by looking into it.
By Age
What to expect by age
0-3 months
Newborns are especially prone to heat rash because their sweat ducts are immature and easily blocked. Miliaria crystallina (clear, tiny blisters) and miliaria rubra (red bumps often called prickly heat) are the most common types. Heat rash in newborns commonly appears on the face, neck, upper chest, and diaper area. It is often caused by overdressing, being held close to a warm body, or being in a warm room. Keep your baby's room at a comfortable temperature (68-72 degrees F), avoid overdressing, and use lightweight, breathable cotton clothing. A cool bath (not cold) can help.
3-12 months
As babies become more active, heat rash may appear in skin folds where moisture accumulates — in the neck creases, behind the ears, in elbow bends, and in the diaper area. Keeping these areas clean and dry is key. After baths, gently pat skin folds completely dry. Avoid thick creams or ointments on the rash, as they can further block sweat ducts. Calamine lotion may provide soothing relief. If your baby has a rash in skin folds that looks raw, weepy, or has an odor, this may be a yeast infection rather than heat rash, which requires different treatment.
12-36 months
Toddlers can develop heat rash during active play, especially in warm weather. The rash often appears on areas covered by clothing or where skin rubs against skin. Prevention is key: dress your toddler in loose, breathable fabrics, take breaks from outdoor play in hot weather, and use fans or air conditioning to keep them cool. Heat rash should resolve within 2-3 days of cooling measures. If the rash worsens, spreads, develops pus-filled bumps, or your child develops a fever, see your pediatrician, as secondary bacterial infection can occasionally complicate heat rash.
What Should You Do?
When to take action
- Small, clear or red bumps appear in skin folds or areas covered by clothing during warm weather and resolve with cooling.
- The rash appears after your baby has been overdressed or in a warm environment and fades within 1-3 days of cooling measures.
- Your baby does not seem bothered by the rash (though some babies may be slightly fussy from the prickly sensation).
- The heat rash does not improve within 3-4 days despite cooling measures.
- The rash recurs frequently and you want advice on prevention strategies.
- You are unsure whether the rash is heat rash, eczema, or another skin condition.
- The rash develops pus-filled bumps, becomes warm and swollen, or has red streaks spreading from it — this may indicate a secondary bacterial infection requiring antibiotics.
- Your baby has a rash accompanied by fever, lethargy, or signs of heat exhaustion — seek medical care to rule out more serious heat-related illness.
- The rash is widespread, blistering, or your baby appears to be in significant distress — see your pediatrician promptly.
Sources
Related Resources
Trust your instincts. If something feels wrong, reach out to your pediatrician.
Worrying about your baby means you care. That is a good thing.
Related Skin Concerns
My Baby Gets Recurring Prickly Heat Rash
Recurring heat rash (miliaria) in babies happens because their sweat glands are immature and easily blocked, especially in hot or humid conditions. Babies who overheat frequently, are overdressed, or live in warm climates are particularly prone to recurrent episodes. Prevention is the best strategy: dress your baby in loose, breathable cotton clothing, maintain a cool environment (68-72 degrees F), keep skin folds clean and dry, and avoid heavy creams that can block pores. Most babies outgrow frequent heat rash as their sweat glands mature.
Signs of Heat Exhaustion in My Baby
Babies are especially vulnerable to heat-related illness because they cannot regulate body temperature as well as adults, have a higher surface-area-to-body-weight ratio, and cannot tell you when they are too hot. Signs of heat exhaustion include excessive fussiness, excessive sweating (or no sweating), flushed or red skin, rapid breathing, vomiting, and lethargy. Heat stroke is a medical emergency where the body temperature rises above 104 degrees F, and the child may become confused, stop sweating, or lose consciousness.
Baby Hives (Urticaria)
Hives are raised, red, itchy welts that can appear suddenly on your baby's skin. They are most often caused by a viral infection or an allergic reaction to food, medication, or an insect bite. While they can look alarming, hives are usually harmless and resolve on their own, though any breathing difficulty needs immediate emergency care.
My Baby Has an Extra Nipple (Accessory Nipple)
Accessory (supernumerary) nipples are one of the most common minor congenital findings, occurring in about 1 in 18 people. They appear as small, flat, often pigmented bumps along the "milk line" — an embryonic line running from the armpit to the groin on each side. Most people mistake them for moles. Accessory nipples are almost always harmless and require no treatment. In rare cases, they may be associated with kidney abnormalities, so some pediatricians recommend a renal ultrasound if one is found, though this practice varies.
My Baby Was Born with a Raw Spot on Their Scalp (Aplasia Cutis)
Aplasia cutis congenita (ACC) is a condition where a baby is born with a small area of missing skin, most commonly on the scalp. It occurs in about 1 in 10,000 births. The affected area may look like a raw wound, an ulcer, or may have already healed into a thin, shiny scar by the time of birth. Most cases are small, isolated, and heal well with basic wound care — the area eventually forms a hairless scar. Larger defects or those associated with other findings may need more investigation, but isolated small ACC has an excellent prognosis.
New Treatments for Atopic Dermatitis (Eczema) in Children
Treatment for atopic dermatitis in children has advanced significantly in recent years. While moisturizers and topical steroids remain first-line treatments, newer options include non-steroidal topical medications (like crisaborole), biologic therapies (like dupilumab, approved for children 6 months and older), and JAK inhibitors. Most children's eczema is well-managed with basic skin care and mild topical treatments, but these newer options provide hope for moderate-to-severe cases.