Reviewed by medical experts • For informational purposes only
Miliaria crystallina, rubra and profunda, and which types need a doctor.
There are three main types of heat rash (miliaria), depending on how deep in the skin the blocked sweat duct is.
Miliaria crystallina
The mildest and most superficial type. Clear, tiny, fluid-filled blisters that look like drops of water appear on the surface. They usually do not itch or hurt and break easily. It is common in newborns and after fever.
Miliaria rubra (prickly heat)
The most common type in hot, humid places. The duct is blocked deeper in the outer skin. It causes red bumps, with itching and a prickling or stinging feeling. The area can be sore. If untreated and skin gets infected, small pus-filled spots can appear, called miliaria pustulosa.
Miliaria profunda
A less common type that affects the deeper layer of skin. It causes firm, flesh-coloured bumps that look like goose bumps. It tends to follow repeated bouts of miliaria rubra, and sweating is reduced in the affected area, which can make the body overheat. It mainly occurs in adults in hot climates and needs medical care.
Related conditions that can look similar
Ayurvedic view
Ayurveda describes heat-related skin eruptions linked to pitta. This is a traditional framework, not a classification used by doctors.
Key point
Most heat rash is crystallina or rubra and resolves with cooling. Deeper or repeated rashes need a doctor.
Before your appointment
Note when the rash began, where it is and what makes it better or worse, such as heat, clothes, creams or sweating. List any products, medicines, oils or herbal pastes you have used, and whether anyone at home has a similar rash. For a baby, note fever, feeding, and what the baby wears and sleeps in. Take photos of the rash over a few days.
Written By
Dr. Daksh
BDS
Reviewed By
Dr. Varun Gupta
MD Pharmacology, MBBS
Last updated on
27 Sep 2022 • 06:23 PM (IST)
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