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Miliaria Crystallina


Miliaria crystallina is a type of heat rash that develops when the eccrine sweat ducts in the uppermost layer of the skin known as the stratum corneum become blocked.

As a result of the blockage, the sweat is unable to evaporate normally and it leaks into the epidermis and dermis which are layers of the skin. This leakage of sweat and its trapping within the skin cause the heat rash.


The cause of the sweat gland blockage is not clear but factors which contribute to their blockage include:

1. Wearing occlusive clothing made from unabsorbent material that restrict perspiration

2. Suffering from febrile illnesses

3. Living in a hot, humid environment.

4. Overheating which can be due to sleeping under an electric blanket or being covered up excessively. For newborns this can also be due to being nursed in a very warm incubator.

5. Applying heavy creams and ointments that block the sweat glands

heat rash skin of color


Symptoms of miliaria crystallina include small, clear vesicles (blisters) which occur in crops. They break easily since they are very fragile. These blisters are neither painful nor itchy.

 heat rash skin of color


Miliaria crystallina is self limiting and treatment involves removing excessive clothing and avoiding hot and humid environments that may trigger excessive sweating.



Do not use a needle to puncture the blisters as you may introduce infection. Leave them to resolve spontaneously.


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Categorised as: Skin Diseases

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