Sometimes called prickly heat, heat rash can affect people of all ages. It is common in babies, but can also affect adults during the summer. When your pores become blocked, sweat gets trapped under your skin. It can cause small red dots or large red bumps on your skin.
The mildest form of this rash is called miliaria crystallina. It affects the top layer of skin and forms clear blisters that can break. It is not painful and usually goes away without treatment. It commonly appears in humid, hot weather.
Miliaria rubra also affects the outer layer of skin, but the rash is deeper in the layer. It is commonly found on infants or adults on bed rest. It causes red bumps on the skin and you may itch or feel prickly.
Unlike the other two kinds of rashes, miliaria profunda affects a deeper layer of the skin called the dermis. It is not as common as the other two types, but it is more common after exercise or excessive sweating. It causes flesh-colored bumps and stops your body from sweating, which can lead to a fast pulse, nausea, or dizziness.
Miliaria crystallina and miliaria rubra are usually harmless, but miliarira profunda may require medical attention. Call your doctor if the area swells or gets very red, warm, or painful. Swollen lymph nodes and pus draining from that area all require a medical attention.
Prevention and Treatment
Heat rash usually disappears on its own, but you can relieve symptoms by reducing how much you sweat. Stay in an air-conditioned room or use fans to cool off. Wear lightweight clothing and avoid exercising.
More severe rashes may require topical treatments. Your doctor may recommend a calamine lotion to control the itch or a topical steroid.