Miliaria

Updated: Nov 14, 2024
  • Author: Nikki A Levin, MD, PhD; Chief Editor: Dirk M Elston, MD  more...
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Overview

Background

Miliaria is a common disorder of the eccrine sweat glands that often occurs in conditions of increased heat and humidity. It is thought to be caused by blockage of the sweat ducts, which results in the leakage of eccrine sweat into the epidermis or dermis. [1]

Miliaria is classified into three main types according to the level at which obstruction of the sweat duct occurs, as follows:

  • Miliaria crystallina - Ductal obstruction is most superficial, occurring in the stratum corneum; clinically, this form of the disease produces tiny, fragile, clear vesicles (see the image below)
  • Miliaria rubra - Ductal obstruction occurs deeper within the epidermis and results in extremely pruritic erythematous papules; when pustules develop in lesions of miliaria rubra, the term miliaria pustulosa is used
  • Miliaria profunda - Ductal obstruction occurs at the dermal-epidermal junction; sweat leaks into the papillary dermis and produces subtle asymptomatic flesh-colored papules
Miliaria crystallina in infant. Note that lesions Miliaria crystallina in infant. Note that lesions are confluent. Image from KE Greer, MD.

Miliaria crystallina is asymptomatic and self-limited and therefore does not require treatment. However, miliaria rubra can cause great discomfort, and miliaria profunda may lead to heat exhaustion. Treatment of these conditions is warranted. (See Treatment.)

Pathophysiology

The primary stimuli for the development of miliaria are conditions of high heat and humidity

 
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