Heat rash is the collective name for skin problems that result from exposure to heat or humidity. Commonly referred to as prickly heat or miliaria, heat rash is particularly prevalent during the summer months and when the climate is humid.

Miliaria is the medical term for the heat-induced rash that can develop following exposure to heat and/or humidity. The rash may form anywhere on the body, but typically, tiny, pink, red or clear bumps develop on areas such as the neck, face, groin, back, elbow folds, buttocks and underneath the breasts.  

Miliaria is caused by particles of sweat becoming lodged within the skin, rather than flowing from the sweat glands to the skin’s outer surface. Human sweat tends to irritate the skin and once trapped, can cause inflammation, redness and itching around sweat pores. The condition is very common among infants, but can also affect adults, particularly after exposure to heat and humidity that may cause sweating.

Treatment

Most cases of miliaria either resolve independently, without treatment being required, or clear up after about one day spent in a cool environment. In rare cases, medication may be prescribed.
Some of the recommendations for the treatment of miliaria are described below.

• Keep cool and keep the skin ventilated. A room temperature of 70 to 72 ˚F is advised. If air conditioning is not available, environments such as hotel lobbies, supermarkets and shopping centers are good alternatives.
• Take cool baths or showers.
• Cleanse the affected skin areas using a gentle soap and then rinse and gently dry. Do this several times a day, especially after engaging in physical activity or being exposed to heat.
• Apply cool blocks or a bag of frozen peas wrapped in a towel to affected areas.
• Place cotton mesh between folds of skin (on the abdomen or under the breast, for example) to prevent skin-to-skin contact.
• Use a cortisone cream to treat any persistent rashes or eczema that may have developed.
• Take any antibiotics prescribed for infection.
• Use antihistamines to relieve itching.
• Drink plenty of water to help stay hydrated and to regulate body temperature.

What to wear

Wearing nothing may make a person feel cooler, but sweat can still accumulate in skin folds. Light, breathable garments made of cotton can help prevent contact between skin folds. Wearing shorts and tops with short sleeves may be helpful. Garments  made of polyester or nylon should be avoided.

References

• https://beta.nhs.uk/conditions/heat-rash
• http://www.mayoclinic.org/diseases-conditions/heat-rash/basics/symptoms/con-20033908
• http://www.aocd.org/?page=Miliaria
• http://www.msdmanuals.com/en-gb/professional/dermatologic-disorders/sweating-disorders/miliaria
• http://lagunaskincenter.com/articles/heat-rash/