Heat Rash (cont.)

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What are the causes of heat rash?

It is uncertain why some people get heat rashes and others don't.

The sweat gland ducts can become blocked if excessive sweating occurs, and that sweat is not allowed to evaporate from a specific area. Some examples of how blockage may occur include the following:

  • Creases in the skin like the neck, armpit, or groin have skin touching adjacent skin, which makes it difficult for air to circulate, and prevents sweat evaporation.
  • Tight clothing that prevents sweat evaporation.
  • Bundling up in heavy clothing or sheets. This may occur when a person tries to keep warm in wintertime or when chilled because of an illness with fever.
  • Heavy creams or lotions can clog sweat ducts.

Babies have immature sweat glands that aren't able to remove the sweat they produce. They can develop heat rash if they are exposed to warm weather, are overdressed, excessively bundled, or have a fever.

Heat rash may occur as a side effect of some medications (for example, isotretinoin [Accutane] or clonidine [Catapres]).

What are the symptoms of heat rash in children and adults?

The common symptoms of heat rash are red bumps on the skin, and an itchy or prickly feeling to the skin. These are due to inflammation of the superficial layers of the skin (the epidermis) and the prickly sensation is similar to the feeling of mild sunburn.

The symptoms of heat rash are the same in infants and adults; however, since an infant can't complain about the rash sensation, he or she may be fussy.

Medically Reviewed by a Doctor on 5/22/2014

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