What is heat rash?

Heat rash, also called miliaria or prickly heat, is a skin irritation that stings and makes your skin red. If you have heat rash, your skin may feel itchy, small bumps may form, and you may feel some “prickly,” tingling pain.

Heat rash occurs most often in hot, humid weather. If you sweat too much, sweat can get trapped under your skin and block your sweat glands. If your pores cannot clear out the sweat, you may get a rash.

Where is heat rash most likely to appear?

Heat rash is most likely to appear in places where skin touches skin, such as the following:

• Neck
• Groin
• Underneath the breasts
• In the creases of the elbows
• Armpits

What causes heat rash?

Heat rash is most common in newborns and infants, but it can also affect adults. It is usually triggered by sweating too much, having a high body temperature, being overdressed or being in a very warm environment. Babies who are bundled in too much clothing and people who are not used to hot weather are most likely to get heat rash.

How can I treat heat rash?

The most effective treatment for heat rash is to keep your skin cool and dry.

• Cool down. Avoid hot and humid places. If possible, stay in air-conditioned areas, or use fans to circulate the air. Use cool compresses to bring down the temperature of the affected skin.
• Dry off. Keep the irritated skin dry. Use a fan to dry the skin off faster and to reduce sweating.
• Reduce friction. Wear loose clothes to prevent irritation caused by clothing that rubs against the skin.
• Treat fever. If you have a fever, treat it with an over-the-counter drug, like acetaminophen (brand name: Tylenol) or ibuprofen (some brand names: Advil, Motrin), according to the directions on the package.

If your rash is severe, your doctor may prescribe a lotion to help relieve your pain or discomfort.

When should I go to the doctor?

In most cases, heat rash goes away on its own. If your heat rash doesn’t go away after 3 or 4 days, or if it seems to be getting worse, talk to your doctor. In some cases, heat rash may be caused by an infection. See your doctor if your itchiness is severe or if the rash area swells or oozes pus. If you feel dizzy, nauseous, or confused, or you have trouble breathing, go to the emergency room right away. These symptoms can be signs of serious heat-related illnesses, such as heat exhaustion or heatstroke.

How can I prevent heat rash?

In hot weather, dress yourself or your baby in lightweight cotton clothing. Cotton helps absorb moisture to keep it off of your skin.

If the weather is hot, turn on the air conditioner, or use a fan to help you stay cool and dry.

Avoid using baby powders and creams. They can block your pores and actually make your skin warmer.

• Is there a treatment that will help?
• What can I do at home to make myself more comfortable?
• Should I let my baby go without a diaper to help clear up the heat rash?
• Should I use diaper ointment on my child?
• What caused my heat rash?
• Should I stop exercising until the heat rash clears up?
• What is the best way to prevent heat rash?