Plus, when you need to seek medical help.

By Maggie O'Neill
June 25, 2020
Advertisement

Spending too much time in the sun can lead to any number of health issues, with a low-grade sunburn falling on the less serious end of the scale and heat stroke falling on the more extreme end. Heat rash is another example of what can happen when you overdo it in the sun—and if it goes untreated, it can do a number on your skin.

According to the Centers for Disease Control and Prevention, heat rash is a skin irritation caused by excessive sweating during hot, humid weather. For this reason, people who sweat excessively are more prone to heat rash, Andrew Alexis, MD, MPH, professor of dermatology at Mount Sinai in New York, tells Health. Heat rash is also most common in young children, though it can affect anyone at any age.

A heat rash occurs when sweat glands get blocked, causing inflammation and, at times, redness, Alok Vij, MD, a dermatologist at Cleveland Clinic, explains. “Often, it’s in areas that have skin-on-skin occlusion,” Dr. Vij adds, explaining that this can mean folds in the abdomen or under the breasts, and it often shows up as red clusters o pimples or small blisters. “[The] red, inflamed bumps on the skin can develop very quickly, within hours of extra sweating,” Dr. Vij says, adding that they can be painful and itchy. The bumps can be painful and itchy, he adds.

If you notice what you assume is a heat rash somewhere on your body, your first step in treating it should be trying to cool down and allowing your skin to breathe. You might want to consider applying a cool water compress to the affected area, Dr. Vij adds. Take a cold shower and allow your skin to dry out, he advises.

Once you've dried off any excess water from cooling down, you can apply an over-the-counter moisturizer, but make sure it isn’t oil-based, Dr. Vij says. (FYI: Oil-based products can clog your pores, which is the exact opposite of what you'll want to do if your sweat glands are blocked.) Dr. Alexis recommends using calamine lotion for quick relief from itching, and to consider using a topical hydrocortisone if your rash looks particularly inflamed to eliminate redness, itching, and swelling.

But if both of those treatments don’t work, it's time to see a doctor. “If that doesn’t resolve it in a matter of days, and the condition continues to worsen, that would be an absolute indication to see a dermatologist,” Dr. Alexis says. If heat rash doesn’t go away after you’ve tried the above remedies, the rash could have become infected. If that’s the case, your dermatologist may prescribe either oral or topical antibiotics, depending on the severity of the rash, Dr. Alexis says. Also worth noting: If you develop heat rash often because of excessive sweating, your dermatologist might try to treat the excessive sweating, possibly through prescription antiperspirants, as a way of getting heat rash under control, Dr. Vij adds.

If you’re worried your heat rash isn’t healing well or fast enough, getting it checked out can’t hurt. Dr. Vij adds that heat rash can mimic bacterial or fungal infections, so it’s important for doctors to get to the bottom of what’s causing the rash if you’re concerned about it. “The most important thing is making sure we’re not missing something else,” he explains.

To get our top stories delivered to your inbox, sign up for the Healthy Living newsletter