Prickly heat is also known as heat rash or miliaria. It is a red and itchy rash on the skin that causes a stinging or prickly feeling, hence the name. Although prickly heat usually occurs in hot conditions, it can affect people in winter if they are wearing too much clothing or sit too close to a heater. Even in summer, the rash is most common on areas of the body that are covered by clothing, but prickly heat can affect any area of the skin.
The rash occurs when sweat glands become blocked, generally as a result of excessive sweating. This is because bacteria and dead skin cells can collect in the sweat glands, trapping the sweat which subsequently bursts out and irritates the skin. The rash itself is usually composed of tiny spots and bumps in an area of red skin.
Prickly heat is not a serious condition and can often be avoided or managed by taking practical steps. For example, spending time in the shade and avoiding exposure to heat will lessen the amount of sweat produced. Loose, cotton clothing will also make sweating less likely than wearing synthetic fabrics. In terms of treatment, calamine lotion both sooths and cools itchy skin, whilst hydrocortisone cream can reduce the itching. However, this should not be applied to the face and as always, it is important to follow the instructions. Generally a prickly heat rash will disappear of its own accord within a couple of days.
A similar condition is polymorphic light eruption (PLE), which is caused by exposure to sunlight. The condition can develop after as little as 20 minutes exposure to the sun, although the itchy spots are often delayed in their onset and may take 5 to 10 days to clear. Unlike prickly heat, it isn’t related to overheating, although prevention methods and treatment are generally the same.
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