Miliaria (miliaria rubra, sweat rash, heat rash, or prickly heat) is a skin disease marked by small and itchy rashes. Miliaria is a common ailment in hot and humid conditions, such as in the tropics and during the summer season. Although it affects people of all ages, it is especially common in children and infants due to their underdeveloped sweat glands.
Symptoms of Heat Rash:
There are two common types of miliaria. The plugged pores of miliaria crystallina result in pinpoint sweat blisters with no redness. The plugged pores of miliaria rubra (prickly heat) produce small red bumps, with or without sweat blisters.
Either way, miliaria tends to show up on covered parts of the skin, especially where there is friction from clothing. The forehead (under caps or visors), body folds, the upper back and chest, and the arms are the most common locations.
Often prickly heat itches in older children, and they often describe a 'prickly' sensation. What newborns feel remains a mystery.
The prickly heat rash can look quite similar to one caused by infected hair follicles (folliculitis), but if you look at the prickly heat bumps with a magnifying glass, no hair follicles will be seen