Heat Rash: Pictures, Causes, Treatments and Symptoms

What is heat rash?

Many different types of skin rashes exist. They can be concerning, uncomfortable, or downright painful. One of the most common types of rash is heat rash, or miliaria.

Heat rash is a skin condition that often affects children and adults in hot, humid weather conditions. You can develop heat rash when your pores become blocked and sweat can’t escape.

The cause of heat rash is often friction on the surface of the skin. Adults usually develop heat rash in the parts of their bodies that rub together, such as between the inner thighs or under the arms. Babies often develop heat rash on their necks, but it can also develop in skin folds such as the armpits, elbows, and thighs.

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Causes of heat rash

It is uncertain why some people get heat rash and others don’t.

The sweat gland ducts can become blocked if excessive sweating occurs, and that sweat is not allowed to evaporate from a specific area. Some examples of how blockage may occur include the following:

• Creases in the skin like the neck, armpit, or groin have skin touching adjacent skin, which makes it difficult for air to circulate, and prevents sweat evaporation.
• Tight clothing that prevents sweat evaporation.
• Bundling up in heavy clothing or sheets. This may occur when a person tries to keep warm in wintertime or when chilled because of an illness with fever.
• Heavy creams or lotions can clog sweat ducts.

Babies have immature sweat glands that aren’t able to efficiently remove the sweat they produce. They can develop heat rash if they are exposed to warm weather, are overdressed, excessively bundled, or have a fever.

Symptoms of heat rash

Adults usually develop heat rash in skin folds and where clothing causes friction. In infants, the rash is mainly found on the neck, shoulders and chest. It can also show up in the armpits, elbow creases and groin.

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Types of heat rash

The types of miliaria are classified according to how deep the blocked sweat ducts are. Signs and symptoms for each type vary.

• The mildest form of heat rash (miliaria crystallina) affects the sweat ducts in the top layer of skin. This form is marked by clear, fluid-filled blisters and bumps (papules) that break easily.
• A type that occurs deeper in the skin (miliaria rubra) is sometimes called prickly heat. Signs and symptoms include red bumps and itching or prickling in the affected area.
• Occasionally, the fluid-containing sacs (vesicles) of miliaria rubra become inflamed and pus-filled (pustular). This form is called miliaria pustulosa.
• A less common form of heat rash (miliaria profunda) affects the dermis, a deeper layer of skin. Retained sweat leaks out of the sweat gland into the skin, causing firm, flesh-colored lesions that resemble goose bumps.

How to diagnosed heat rash

Heat rash can usually be identified by its appearance and does not usually require medical attention. But if it doesn’t go away after 3 or 4 days, or if it appears to be getting worse, or if your child develops a fever, contact your doctor right away.

When you or your child has a rash, be sure to watch for signs of infection, including:

• Increased pain, swelling, redness, or warmth around the affected area.
• Red streaks extending from the affected area.
• Drainage of pus from the area.
• Swollen lymph nodes in the neck, armpit, or groin.
• Fever of 100.4°F (38°C) or higher, or chills with no other known cause.

Prevention of heat rash is the best treatment for heat rash. Avoid hot environments and take refuge in cooler environments. Air conditioners, oscillating fans, and limiting physical activity in a hot environment can help prevent heat rash. Home remedies for treating heat rash include washing the affected area with a mild soap and rinsing the area, then gently dry the area. Over-the-counter remedies applied to the affected areas may help. Wear clothing that allows the skin to breathe in a hot environment. Stay hydrated and drink plenty of water to prevent dehydration in hot environments. Medical care may be necessary if the heat rash does not resolve with home remedies.

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