Heat rash

Heat rash also is called prickly heat, sweat rash or miliaria. It happens when blocked sweat ducts trap sweat under the skin. One type of heat rash, called miliaria rubra (A), has red clusters of small bumps that look like blisters. They can be itchy. Another type, called miliaria crystallina (B), has clear, fluid-filled bumps.

Heat rash isn't serious. It usually goes away quickly when the skin cools. Until the rash fades, decrease sweating by staying in an air-conditioned space or using a fan to circulate the air. Wear lightweight clothing and avoid intense physical activity. Put a cool, wet cloth on the skin or soak in a cool bath for more relief.