Skip to content
    Font Size
    A
    A
    A

    Understanding Heat Rash -- the Basics

    What Is Heat Rash?

    Heat rash -- also called prickly heat or miliaria -- is a common condition in which areas of the skin feel prickly or sting due to overheating. Heat rash looks like tiny bumps surrounded by a zone of red skin. It usually occurs on clothed parts of the body, such as the back, abdomen, neck, upper chest, groin, or armpits and usually gets better once the skin is cooled.

    Heat rash occurs most often in hot, humid conditions. It's most common in infants. Active people, newborns in incubators, and bedridden patients with fever also are more likely to get heat rash.

    What Causes Heat Rash?

    heat rash

    Heat rash begins with excessive perspiration, usually in a hot, humid environment. The ducts from the sweat glands in the skin become blocked. This causes the sweat to leak into the surrounding tissue, causing irritation and redness. You may feel the prickly, or stinging, sensation that gives this condition its name.

    WebMD Medical Reference

    Reviewed by Melinda Ratini, DO, MS on April 14, 2015

    Today on WebMD

    chafing
    Pictures and symptoms of the red, scaly rash.
    woman with dyed dark hair
    What it says about your health.
     
    woman with cleaning products
    Top causes of the itch that rashes.
    atopic dermatitus
    Identify and treat common skin problems.
     
    itchy skin
    Article
    shingles rash on skin
    Article
     
    woman with skin tag
    Quiz
    Woman washing face
    Video
     
    woman washing her hair in sink
    Video
    close up of womans bare neck
    Tools
     
    Feet
    Slideshow
    woman with face cream
    Quiz