Overview. Heat rash (miliaria rubra), also known as prickly heat, is a rash of small red bumps caused by blockage of the sweat glands. It can be due to high fever, excessive sweating, or being over-bundled.
Feb 19, · Miliaria rubra is the most common form of miliaria. It is seen in children and in up to 30% of adults who move to a tropical environment or are unexpectedly exposed to heat and humidity. Miliaria profunda is rare and presents in adult males. It is a complication of repeated episodes of miliaria rubra.
Miliaria is a dermatologic manifestation of occluded eccrine sweat glands. Two features are needed for development of the rash: an anatomical blockage of the duct and a stimulus for sweat production.