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What is Prickly Heat Rash?

Tricia Christensen
Tricia Christensen
Tricia Christensen
Tricia Christensen

Miliaria rubra or prickly heat rash is a prickling and/or itchy rash that may take the form or red bumps confined to different areas of the body. These are usually small and possibly blister-like in appearance. They represent what has occurred as result of exposure to heat and usually humid conditions. Sweat glands get partially occluded by skin cells that are dead, somewhat similar to the way pimples like whiteheads form in the pores.

A few groups of people may be more prone to prickly heat rash, and for different reasons. People who have periods of wet heat weather are more likely to get this kind of rash. It’s also a fairly common reaction in diapered babies and older children, particularly as temperatures rise. Sudden exposure to a great deal of heat in or outside might make people more prone to prickly heat rash, too. Occasionally a fever produces prickly heat and exercise with profuse sweating could cause it.

The obese may notice a prickly heat rash where the stomach overhangs the pelvis.
The obese may notice a prickly heat rash where the stomach overhangs the pelvis.

There does seem to be a tendency for prickly heat rash to most often form in areas where the body is naturally warmer. In the various bends in bodies like the underarms, miliaria rubra may more easily be present, and it can appear in other skin folds, such as beneath the breasts. Those who are obese might notice this rash under the stomach, where it overhangs the pelvis.

A heat rash is characterized by a reddish rash that is caused by excessive heat.
A heat rash is characterized by a reddish rash that is caused by excessive heat.

Under most circumstances, treating prickly heat rash is fairly straightforward. People are advised to keep cool and taking cool showers or bathing might be recommended as a means of avoiding further development of the rash. Topical medications that contain hydrocortisone could be recommended to reduce inflammation, and there’s suggestion that washing with antibacterial soap might help a rash resolve sooner. Any creams used on the rash should be water-based, because oil based creams could block the sweat glands.

Topical antibiotic lotions or ointments may work to treat an infected prickly heat rash.
Topical antibiotic lotions or ointments may work to treat an infected prickly heat rash.

In a few instances, the rash gets worse and might become infected. People should see a doctor to determine how to handle infection. Topical antibiotic lotions might work, but real infection could also raise risk for sepsis or blood infection. Oral antibiotics may be prescribed instead, particularly if infection is profuse.

Sometimes a case of prickly heat is not so simple and a condition called miliaria profunda develops. The sweat glands become severely impaired, and they may produce a rash that burns and usually is not red, but is instead more the color of the skin or is white. This can put people at risk for heatstroke because the body is unable to cool itself down. People should definitely contact a physician if this type of prickly heat rash develops, but should do so while making every effort to stay cool.

Tricia Christensen
Tricia Christensen

Tricia has a Literature degree from Sonoma State University and has been a frequent WiseGEEK contributor for many years. She is especially passionate about reading and writing, although her other interests include medicine, art, film, history, politics, ethics, and religion. Tricia lives in Northern California and is currently working on her first novel.

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Tricia Christensen
Tricia Christensen

Tricia has a Literature degree from Sonoma State University and has been a frequent WiseGEEK contributor for many years. She is especially passionate about reading and writing, although her other interests include medicine, art, film, history, politics, ethics, and religion. Tricia lives in Northern California and is currently working on her first novel.

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Discussion Comments

anon213050

I've had heat rash for years on my back and shoulders. I started using Reef Relief about two months ago and it's worked great so far.

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    • The obese may notice a prickly heat rash where the stomach overhangs the pelvis.
      By: bacalao
      The obese may notice a prickly heat rash where the stomach overhangs the pelvis.
    • A heat rash is characterized by a reddish rash that is caused by excessive heat.
      By: defun
      A heat rash is characterized by a reddish rash that is caused by excessive heat.
    • Topical antibiotic lotions or ointments may work to treat an infected prickly heat rash.
      By: Coprid
      Topical antibiotic lotions or ointments may work to treat an infected prickly heat rash.
    • A cool bath can slow the development of prickly heat rash.
      By: Gabriel Blaj
      A cool bath can slow the development of prickly heat rash.