Jami L Miller, MD
Section Editor:
Cindy Owen, MD
Deputy Editor:
Abena O Ofori, MD
Literature review current through: Oct 2023.
This topic last updated: Sep 07, 2021.


Eccrine miliaria (miliaria) is a common, transient cutaneous disorder caused by blockage within the eccrine sweat duct. It is also known as "sweat rash," "prickly heat," or "heat rash." There are three main types of miliaria (crystallina, rubra, and profunda), which are distinguished by clinical appearance as well as histologic findings (picture 1A-D). The type of miliaria that develops depends upon the level at which the duct is blocked.

The clinical features, diagnosis, and management of miliaria will be reviewed here.


Miliaria occurs most commonly under conditions of sweating. It is found in both children and adults:

Miliaria crystallina, also known as sudamina, is very common in neonates. Incidence peaks at approximately one week of age. Reports of frequency range from 4.5 percent [1] to 9 percent [2]. It has also been reported in adults. Congenital miliaria crystallina has been described.

Miliaria rubra is the most common type. It has been reported in 4 percent of neonates [1] and in up to 30 percent of people of all ages [3]. Miliaria pustulosa is an uncommon variant of miliaria rubra that has been most frequently reported in neonates [4]. (See 'Clinical manifestations' below.)

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