Miliaria results from plugging or rupture of sweat ducts. It occurs in hot humid climates, at any age. The physical signs depend on where the ducts are blocked. According to the level of pathology within eccrine sweat duct there are three types of miliaria:
1. Miliaria crystalina (the most superficial type)
2. Miliaria rubra (the commonest type)
3. Miliaria profunda (the deepest type)
Miliaria rubra (prickly heat) is characterized by tiny erythematous and very itchy papules. Sometimes it presents as widespread erythematous patches with surface cracking and associated with burning sensation especially on the back and flexures of obese persons as in the presented patient who works as a porter (carrier) for many hours aday at hot humid weather.