4 best ways to treat baby heat rash

When Michele Ramien’s son was a year old, her family travelled to the Dominican Republic for a little R & R. As a dermatologist, Ramien was hypervigilant about protecting her baby’s delicate skin from the sun’s rays, so she slathered him in a thick sunscreen. Unfortunately, it turned out to be too much of a good thing. “He developed a heat rash on the first day, and we ended up having to stay out of the heat for most of the vacation,” says Ramien.

What causes baby heat rash?

Ramien, who is also a clinical associate professor at the Alberta Children’s Hospital in Calgary, says that while staying indoors was also good sun protection, it wasn’t really what she had planned for their tropical holiday. But heat rash is extremely common in babies, and anything that prevents the skin from breathing—from being exposed to excessive heat and humidity to overdressing and being swaddled in too many layers to applying too much cream—can cause the condition. Although older kids and adults can get heat rash (also known as miliaria), Ramien says it’s most common in newborns because their sweat glands aren’t fully mature.

What does heat rash look like?

Parents often worry when they encounter heat rash for the first time because it can look quite red and pimply if the sweat glands are completely blocked, but it can also be mild and present in clear little bumps. “It can look like small droplets of sweat are stuck under the skin,” says Julia Orkin, a paediatrician at the Hospital for Sick Children in Toronto and chair of the Canadian Paediatric Society's Community Paediatrics Committee.“These bumps usually appear in areas where infants sweat the most, like the forehead, neck, shoulders and chest.” You can tell a heat rash from other skin conditions because it’s always related to heat or sweating, adds Ramien. Often, a rash is the only symptom, but if your baby has prickly heat (a common type of heat rash), the skin may also be red and itchy because the blockage is deeper in the sweat glands and the skin around the pores is more irritated.

When to see a doctor

“A heat rash is a relatively benign condition that should never make a baby unwell,” says Ramien. In rare cases, though, it may develop into a more serious bacterial infection. You should see a doctor if your baby is in pain, develops a fever or has any discharge from the bumps. In most cases, you can treat heat rash at home and it will clear up within a couple of days. If it hasn’t cleared up or if you’re concerned about it, check with your doctor.

How do you deal with baby heat rash?

1. Get out of the heat

Heat and humidity can cause and exacerbate heat rash, so turn the temperature down a notch or two or put your baby in a room with a fan or air conditioning to help cool off.

2. Draw a bath

Give your baby a lukewarm bath. It should be "cooling" but still be comfortable for your child. Ramien recommends skipping the soap and just using water to avoid blocking pores any further. Let your baby air-dry instead of rubbing skin with a towel.

3. Dress in light clothing

If possible, let your baby go au naturel for a while and wear light, loose-fitting clothing. “Natural fibres, such as cotton and hemp, are generally lightest and most breathable,” says Ramien.

4. Skip the lotion

Although it might be tempting to apply a soothing lotion to your baby’s skin, it’s best to resist the urge. Cool compresses can help relieve the itchiness associated with prickly heat, but it’s a good idea to check with your doctor before applying any creams and lotions to the affected areas.