Heat bumps, also called prickly heat or heat rash, usually clear up within a day or two once you cool your skin down and stop the cycle of sweat duct blockage that caused them. The rash forms when sweat gets trapped beneath your skin instead of evaporating, creating tiny inflamed bumps that can itch, sting, or feel prickly. Getting rid of them is mostly about removing the trigger and helping your skin recover.
Cool Your Skin Down First
The single most effective thing you can do is get out of the heat. Move to an air-conditioned room, stand in front of a fan, or find shade. The goal is to stop sweating so your blocked sweat ducts can open back up. Most uncomplicated heat rash resolves without any treatment at all once you’re in a cooler environment.
For immediate relief, press a cool, damp cloth against the affected area or take a cool shower or bath. Avoid hot water, which will keep your sweat glands working overtime. If the bumps are on your neck, chest, or back, letting those areas air-dry rather than toweling off aggressively can help avoid further irritation.
Treat the Itch With the Right Products
If the bumps are itchy or inflamed, a 1% hydrocortisone cream (available over the counter) applied three times a day to the irritated spots can reduce swelling and discomfort. One important detail: use the cream formulation, not an ointment. Ointments are thicker and greasier, and they can actually block your sweat glands further, making the problem worse. Calamine lotion is another option that soothes itching and has a light, drying effect on the skin.
Avoid applying heavy moisturizers, petroleum jelly, or any thick product to the rash. These seal moisture against the skin and prevent your sweat ducts from draining normally.
What You Wear Matters
Tight clothing traps heat and moisture against your skin, which is exactly what caused the bumps in the first place. Switch to loose-fitting clothes that allow air to circulate. Cotton is the classic recommendation because it’s soft and breathable, though it does absorb moisture and stays damp. For situations where you’re actively sweating (exercise, outdoor work), moisture-wicking fabrics like polyester or nylon pull sweat away from your skin and dry quickly, keeping the surface drier.
Merino wool and bamboo blends also manage heat well. Mesh or perforated designs improve airflow even further. The key principle is that air needs to move over your skin. If you can leave the affected area uncovered entirely, that’s even better.
Three Types of Heat Bumps
Not all heat rash looks the same, and knowing which type you have helps set expectations for how quickly it will clear.
- Miliaria crystallina: The mildest form. Sweat gets trapped just below the outermost layer of skin, producing tiny, clear, fluid-filled blisters that aren’t red or painful. These often disappear within hours of cooling down.
- Miliaria rubra: The most common type, and what most people mean by “heat bumps” or “prickly heat.” The blockage is deeper, causing red, inflamed bumps that itch or sting. This is the type that typically takes one to two days to resolve.
- Miliaria profunda: The least common but most stubborn form. Sweat leaks into a deeper layer of skin, producing firm, flesh-colored bumps. This type can take longer to clear and sometimes recurs in people who are repeatedly exposed to hot, humid conditions.
Preventing Heat Bumps From Coming Back
Keeping your skin cool and dry is the core strategy. Use air conditioning and fans to manage indoor temperatures. When you’re outside in the heat, take frequent breaks in cooler spaces rather than pushing through hours of continuous sun or humidity exposure. Shower promptly after sweating to wash away the salt and debris that can clog sweat ducts.
Pay attention to where your heat bumps tend to appear. Common spots are skin folds, the chest, back, and anywhere clothing sits snugly. If you consistently get heat rash in the same area, that’s a signal to adjust your clothing fit or find ways to improve airflow to that spot. Sleeping in a cool room with minimal bedding also helps, especially in summer months when overnight sweating is a common trigger.
Heat Bumps in Babies and Young Children
Infants are especially prone to heat rash because their sweat ducts are smaller and more easily blocked. The same cooling principles apply, but with a few extra considerations. Dress babies in thin, loose cotton clothing, and leave the affected skin exposed to air when possible. Avoid thick ointments or creams on infants unless directed otherwise by a pediatrician. Greasy products block immature sweat glands even more readily than in adults.
Clothing for babies should be loose enough to allow airflow but not so loose that it bunches up or wraps around the child. In hot weather, a single layer of lightweight clothing is often enough.
Signs the Rash Needs Medical Attention
Heat bumps occasionally become infected with bacteria, turning into pus-filled bumps that are more painful and inflamed than typical heat rash. If your rash hasn’t improved after a few days of cooling measures, is getting worse instead of better, or develops signs of infection like increasing redness, warmth, swelling, or drainage, it’s worth having a provider look at it. A bacterial infection in heat rash may need a prescription treatment to clear.