A heat rash can appear suddenly and look alarming, but it is usually not a cause for concern. Babies have delicate skin and are more likely to get heat rash than adults. Heat rash, which some people call prickly heat or heat rash, is a breakout on the skin that occurs after the skin becomes too hot. These rashes can be itchy, uncomfortable, and burning.
Why Do Babies Get Heat Rash?
Heat rashes appear when sweat is trapped under the skin. Because babies have smaller sweat glands and are less able to regulate their body temperature, they are more vulnerable to heat rash than adults.
Tight clothing, diapers, and blankets can also cause heat rashes. In most cases, the rash will go away on its own without treatment. Babies are more likely to get a rash for several reasons:
- Babies have little control over their surroundings and cannot remove extra clothing or stay away from heat sources.
- Babies’ bodies are less effective at regulating temperature.
- Babies tend to have more folds in their skin, which can trap heat and sweat.
Types of heat rash
Miliaria occurs when the skin traps sweat. Sweat irritates the outer layer of the skin and causes a rash. Doctors divide heat rash into three types based on its severity:
- Miliaria ruba is the most common type of heat rash. This type of rash occurs when there is a blockage in the sweat glands near the surface of the skin, or the epidermis, and the second layer of skin, or the dermis. It causes bumps, discoloration such as redness and itchiness.
- Miliaria crystallina is the least severe form of heat rash. It occurs when there is a blockage in the sweat glands in the epidermis. This type of heat rash can cause small clear or white blisters.
- Heat rash is the most serious type, but it is rare. When sweat in the dermis seeps into the dermis, it can cause severe redness and burning. Babies with deep miliaria can also develop signs of heat exhaustion. The rash can become infected.
With rashes that cause redness, the redness may be easier to see on fair skin and harder to see on dark skin, although the process that causes the redness is the same.
Doctors call the tiny blisters of a gallbladder a heat rash. Sometimes these vesicles become inflamed, causing pustular miliaria. This type of heat rash is more common in babies. Babies with miliaria pustulosa may have less ability to sweat, which increases the risk of heat-related illnesses.
Symptoms and diagnosis
For most babies, the only symptom of a heat rash is a rash on parts of the body that have been exposed to heat. Wrapping, warm clothing, poor ventilation, and being near heat sources, such as heaters, can increase your risk. A caregiver might notice a rash on an area of the body that was particularly hot. Heat rashes are also more likely to appear in skin folds, such as on the neck or groin.
Symptoms of heat rash include:
- A rash that may appear red.
- Small pin-sized blisters on a large area of the skin.
- Hot skin
Different types of heat rash may have slightly different symptoms:
- Miliaria crystallina can sometimes appear similar to tiny beads of sweat trapped under the skin. The blisters do not look red or inflamed.
- Miliaria rubra is often itchy, so babies can persistently scratch their skin. They may have small red bumps or blisters on red, irritated patches of the skin.
- Deep miliaria usually causes deep blisters that can look like pimples. They are usually skin-colored.
- Miliaria pustulosa causes irritated pustules that look like blisters do. They may crust or break open and bleed.
In most cases, the heat rash clears up fairly quickly and doesn’t cause too much discomfort, so a doctor’s visit may not be necessary. The signs of a heat rash are obvious, especially in hot weather. If a doctor is unsure about a rash, a doctor can usually diagnose the rash based on its appearance.
Treatments and home remedies
Heat rash usually clears up on its own within a few days without treatment. Caregivers can ease a baby’s discomfort and speed healing with the following methods:
- Move your child to a cool area at the first sign of a heat rash.
- Keep the skin cool and dry.
- Apply a cold compress to the affected area.
- Rinse off the oil and sweat with cold water, then gently pat the area dry.
- Regularly wipe skin folds to make sure trapped sweat and oil don’t make the rash worse.
- Allow baby to undress to keep skin cool.
- Use air conditioning or fans to help keep skin cool.
- Keep the baby well hydrated. This may involve breastfeeding babies who need it and ensuring that older babies have constant access to water.