Miliaria rubra is a type of heat rash or prickly heat that happens when sweat becomes trapped under the skin. Children tend to get it more than adults because their sweat glands are still developing.

The severity of the heat rash, also referred to as "prickly heat" or "miliaria," depends on how deep the sweat is trapped underneath the skin. Start the day smarter. Get all the news you need in ...