Heat rash clears up quickly once you cool your skin down. Most mild cases resolve within one to two days, and the core treatment is simple: get out of the heat, let your skin breathe, and avoid anything that clogs your pores. More severe cases can take a week or longer, but the approach stays the same.
Cool Your Skin First
The single most important step is lowering your skin temperature. Press a cool, damp cloth against the rash, or take a cool shower or bath. Let your skin air-dry afterward rather than rubbing it with a towel. Move to an air-conditioned room or position a fan so it blows gently over the affected area. Heat rash happens when sweat gets trapped beneath your skin, so everything you do should aim at stopping the sweating and unclogging those blocked pores.
Once the skin cools, mild heat rash tends to clear on its own without any medication. You don’t need to apply anything to it in most cases. In fact, applying the wrong product can make things worse.
What to Put on It (and What to Avoid)
Skip oily or greasy moisturizers, heavy sunscreens, and cosmetics on the affected skin. These products can block pores further and trap more sweat underneath. If the skin feels dry or irritated, use a moisturizer containing anhydrous lanolin (wool fat), which helps prevent sweat ducts from clogging.
Calamine lotion can soothe itching. Over-the-counter hydrocortisone cream in a low strength may help if the itch is persistent, but keep the layer thin. The goal is always to let the skin breathe.
What to Wear While It Heals
Fabric choice matters more than most people realize. Linen is the best option for hot, humid conditions. Its fiber structure absorbs moisture quickly and transports it away from the body faster than cotton or polyester. Linen also has a natural stiffness that keeps it from clinging to your skin, which allows air to circulate underneath the fabric.
Cotton is a decent second choice, especially in drier heat or for shorter stretches outside. It absorbs moisture well but holds onto it longer than linen, so it can start to feel clammy. Regular polyester is a poor choice because it barely absorbs moisture at all. The exception is moisture-wicking polyester (like Dri-FIT fabrics), which is designed to pull sweat away from the skin and works well during physical activity.
Whatever you wear, keep it loose. Tight clothing traps heat and friction against already irritated skin. Leave the affected area uncovered when you can.
Treating Heat Rash in Babies
Babies and young children are especially prone to heat rash because their sweat ducts are smaller and clog more easily. The treatment principles are the same, with a few extra considerations. Cool your child with a lukewarm bath or cool moist compresses, then dry the skin completely. Pay special attention to skin folds that collect sweat and drool: the neck, armpits, elbow creases, and behind the knees.
Dress your baby in thin, loose-fitting cotton clothing. It should be loose enough for airflow but not so loose that it could tangle or wrap around the child. Leave the rash exposed to air when possible. Use a fan or air conditioning to keep the room cool, and avoid thick, greasy ointments on the rash since these block sweat glands.
The Three Types and Why Severity Varies
Not all heat rash looks the same. The severity depends on how deep in the skin the sweat gets trapped.
- Mildest form: Sweat is blocked right at the skin’s surface. You’ll see tiny, clear, fluid-filled bumps that break easily. This type usually isn’t itchy and resolves fastest.
- Moderate form (prickly heat): Sweat is trapped deeper. The bumps are small, inflamed, and blister-like, with noticeable itching or a prickling sensation. Sometimes these bumps fill with pus, which looks alarming but doesn’t necessarily mean infection.
- Deepest form: Sweat is trapped in the deepest layer of skin. This produces firm, painful bumps that resemble goose bumps and may break open. This type is the least common but takes the longest to heal.
The mild and moderate forms respond well to home cooling measures. The deepest form may need medical attention, especially if it keeps recurring.
Signs the Rash Needs Medical Attention
Heat rash can occasionally lead to a bacterial skin infection, particularly if scratching breaks the skin and allows bacteria in. Watch for skin around the rash that becomes swollen or feels warm to the touch, or any fever, nausea, or chills. These are signs of infection, not just irritation.
You should also see a provider if the rash hasn’t improved after a few days of cooling measures, if it’s intensely painful or itchy beyond what feels like normal irritation, or if you suspect something other than heat is causing it. Conditions like eczema, contact dermatitis, and fungal infections can look similar to heat rash but require different treatment.
Preventing It From Coming Back
If you’ve had heat rash once, your sweat ducts may be more prone to clogging in similar conditions. On hot days, take breaks in cool or shaded environments before you start sweating heavily. Shower promptly after exercise or heavy sweating and change out of damp clothes. Choose linen or moisture-wicking fabrics when you know you’ll be in the heat for extended periods. Keep skin folds clean and dry, and avoid layering heavy creams or sunscreens on areas where you tend to sweat most.