Prickly heat (also called heat rash, sweat rash, or miliaria) is a rash of red or pink dots that appears over an infant's head, neck, and shoulders. The dots look like tiny pimples. The rash from prickly heat usually covers a small area and is considered a localized rash. Occasionally the rash will cover a larger area (generalized rash).

Prickly heat is often caused when well-meaning parents dress their baby too warmly, but it can happen to any baby in very hot weather. A baby should be dressed as lightly as an adult who is resting. Your baby's hands and feet may feel cool to the touch. This is not uncommon and is usually not a problem.