The best things to put on a heat rash are calamine lotion to soothe itching, a cold compress to calm inflammation, and a low-strength hydrocortisone cream if the itch is persistent. Most heat rashes clear up within a few days once you cool the skin and stop trapping moisture against it. The specific treatment depends on how severe your rash is and whether it’s just annoying or genuinely painful.
Calamine Lotion
Calamine lotion is the go-to first choice for heat rash. It cools on contact, reduces itching, and dries out the tiny blisters that form when sweat gets trapped under your skin. Apply a thin layer directly to the rash and let it air dry. You can reapply as needed throughout the day. It’s safe for children and doesn’t require a prescription.
Cold Compresses
A damp cloth or ice pack wrapped in a towel, held against the rash for up to 20 minutes, provides fast relief from the prickling sensation. This works especially well right after you come inside from heat exposure. The cold narrows blood vessels near the skin’s surface, which reduces redness and swelling. You can repeat this several times a day.
One important habit to build: tap or pat the rash instead of scratching it. Scratching breaks the skin and opens the door to infection, which turns a minor annoyance into a real problem.
Hydrocortisone Cream
If calamine and cold compresses aren’t cutting it, a 1% hydrocortisone cream (available over the counter) helps reduce inflammation and itching. Apply a thin layer one to four times a day, depending on how irritated the area is. Don’t use it for more than a week without checking with a pharmacist or doctor, and avoid it on children under 10 unless a doctor has specifically recommended it.
Hydrocortisone works by dialing down the immune response in that patch of skin, so the redness and swelling settle faster. It’s not meant for large areas of the body or for long-term use.
Oatmeal Baths and Baking Soda
Colloidal oatmeal, the finely ground type sold specifically for baths, forms a protective film on the skin that locks in moisture and calms itching. You can add it to a lukewarm bath (not hot, which will make a heat rash worse) and soak for 10 to 15 minutes. It’s also available in lotions you can apply directly to the rash.
Baking soda offers similar itch relief. You can mix a small amount with water to make a paste and dab it onto the rash, or add a few tablespoons to a cool bath. Neither remedy speeds up healing on its own, but both make the waiting period more comfortable.
What Not to Put on Heat Rash
Avoid perfumed shower gels, scented lotions, and heavy creams. Fragrances irritate already-inflamed skin, and thick moisturizers can seal sweat ducts shut, which is exactly what caused the rash in the first place. Petroleum-based ointments fall into the same category. You want your skin to breathe, not be sealed under a layer of product.
Know Your Type of Heat Rash
Not all heat rashes are the same, and what you put on yours partly depends on which type you’re dealing with.
The mildest form produces tiny, clear, fluid-filled bumps that break easily. It looks almost like small water droplets sitting on the skin. This type usually resolves on its own without any treatment beyond cooling off.
The most common type, often called prickly heat, shows up as small, inflamed, blister-like bumps with noticeable itching or a prickling sensation. This is the one most people are searching for help with, and it responds well to calamine, hydrocortisone, and cold compresses.
The least common form affects deeper layers of skin and produces firm, painful bumps that resemble goose bumps. These can break open and are more likely to need medical attention. Topical treatments alone may not be enough for this type.
Signs of Infection
A heat rash that’s getting worse instead of better after two or three days, or one that starts producing pus, increasing pain, warmth, or swelling around the bumps, may have become infected. Fever alongside a worsening rash is another red flag. Scratching is the most common way bacteria get into heat rash bumps, which is why patting instead of scratching matters so much. An infected heat rash typically needs prescription treatment rather than over-the-counter options.
Preventing It From Coming Back
What you wear matters as much as what you apply. Linen is the best fabric for heat rash prevention. Its fiber structure absorbs moisture quickly and moves it away from the body faster than cotton or polyester. Linen is also stiffer than cotton, which keeps it from clinging to sweaty skin and allows air to circulate between the fabric and your body.
Cotton is a decent second choice, though it absorbs water and holds it, which means it can stick to your skin and stay damp. Regular polyester is the worst option for moisture absorption. However, moisture-wicking polyester blends designed for athletic wear perform well during exercise because they’re engineered to pull sweat to the fabric’s surface where it evaporates.
Beyond fabric choices, the basics apply: stay in air conditioning or shade during peak heat, shower promptly after sweating, and let skin folds (under breasts, in elbow creases, behind knees) dry completely before getting dressed. Loose-fitting clothes give your sweat ducts room to do their job. Once you cool and dry your skin consistently, most heat rashes clear within a few days without any other intervention.