Sweat Rash Information

See Also: Chafing - Infected Sweat Rash - Excessive Sweating - Fungal Infections - Skin Irritation - Sweat Rash - Itching

About Sweat Rash

Sweat rash, also known as prickly heat, heat rash and miliaria, is a common skin disease that affects most people at some point in their lives.

As the name suggests, sweat rash (miliaria) is a rash that commonly affects people in hot and humid conditions. The condition is characterised by small, localised, itchy rashes that develop on the skin, usually in places such as the face, neck and skin fold areas. The rash is itchy, bothersome and often accompanied by an unpleasant burning or prickling sensation (like pins-and-needles, hence prickly heat).

Sweat rash can be a particular nuisance for sufferers, as not only is it uncomfortable to deal with, it is also unpleasant to look at.

Causes of Sweat Rash

Sweat rash occurs when the ducts of the sweat glands get blocked by dead skin cells or bacteria. This traps sweat below the surface of the skin, which cause irritation and inflammation. The condition is common amongst individuals in hot, humid conditions, particularly when they sweat more than they usually do. Athletes and the physically active are also susceptible to heat rash, but it is most widespread in babies and young children. This is because their sweat glands are immature and more prone to blocking.

Symptoms of Sweat Rash

The most common symptoms of sweat rash (miliaria) are sore, red, inflamed skin, extreme itchiness and an unpleasant burning or pins-and-needles sensation. The irritation is grouped in small rashes that can occur in one or more areas on the body, particularly the face, neck, back of knees, chest, armpits, under the breasts and other skin fold areas.

Due to the block sweat ducts, a lack of sweating (anhidrosis) can also be apparent in the rash covered areas. If large areas are affected, there could be a danger of developing a high fever or heat exhaustion as without sweat, the body is no longer be able to regulate body heat correctly.

Types of Sweat Rash

There are several classified types of sweat rash (miliaria).

• Miliaria rubra is the most commmon form of miliaria and the one most likely to be referred to as sweat rash, heat rash or prickly heat. In cases of miliaria rubra, the sweat ducts become blocked deep in the epidermis, causing sweat to seep into the deeper layers of outer skin and cause inflammation. The symptoms of miliaria rubra are the same as the symptoms given above, i.e., sore, red skin, small, bumpy red spots forming a rash and sensations of itching or prickliness. A lack of sweating (anhidrosis) can also be apparent in the affected area. The rash can appear in several areas of the body at once.



• Miliaria crystallina is perhaps the least bothersome form of sweat rash. The sweat ducts become blocked towards the surface of the skin, creating a rash of small, clear blister-like spots that resemble beads of sweat. In most cases there will be little or no itching and the spots will disappear within a few hours.



• Miliaria profunda is the most severe form of sweat rash and also the least common. The sweat ducts become blocked deep down in the structure of the sweat gland, in the dermis (the middle layer of skin). This causes the sweat to leak into the deeper layers of skin, creating a flesh-coloured rash with bigger bumps but little itching. With this type of heat rash, the risk of heat exhaustion is greater.

Treating Sweat Rash

If you are prone to sweat rash, then taking the necessary steps to prevent the condition occurring is often the best solution.

• Taking simple steps, such as avoiding hot, humid weather and activities that induce sweating, even if just for a few hours a day, will make a big difference. Some find that taking frequent, cool showers or baths helps, as does taking advantage of air conditioned rooms wherever possible. Wearing loose fitting cotton clothing that allows air to circulate around your body, is another good idea.



• When bathing or showing, using a mild antibacterial soap or antiseptic wash, while not proven to help, is always a good idea as it has been suggested they may reduce the symptoms of heat rash.



• An itch-reducing preparation, such as calamine lotion or a menthol or camphor based product, will help to cool and soothe the skin, while reducing the temptation to scratch at the rash. A hydrocortisone cream will help calm the inflammation and irritation of the condition. It is wise to avoid oil-based products as these can aggravate sweat rash.

In most cases of miliaria, the rash will clear up without any treatment, but if this your first time experiencing such a rash, it is advisable to always get it checked out by a doctor first.

Fungal Sweat Rash

The term 'sweat rash' is often, though not entirely correctly, applied to a condition known as candidal intertrigo, or 'thrush of the skin folds' (the condition is also commonly referred to as candidal sweat rash, fungal sweat rash or infected sweat rash).

Intertrigo is a yeast infection caused by Candida albicans, a fungus naturally present on the skin. Common sweat rash (miliaria) is often a trigger for fungal sweat rash. Trapped sweat, or indeed excessive perspiration, can upset the natural balance of the skin, leading to an overgrowth of Candida albicans. This can cause an itchy, irritating and unsightly red rash.

Common symptoms of fungal sweat rash to look out include:

• inflamed skin
• a sore red rash
• itching
• a burning sensation
• broken, moist skin.

Infected sweat rash is most likely to occur as a result of sweating during exercise or warm weather. It commonly affects areas where the skin rubs together (chafes), such as under arms, breasts, behind the knees, in the groin area or anywhere where clothes rub against the skin. It can be treated using a cream, spray or powder containing hydrocortisone (an anti-inflammatory) and an antifungal agent such as clotrimazole. For more information, please visit our candidal sweat rash page.