Heat rash definition and facts.
Heat rash occurs when the skin’s sweat glands are blocked and the sweat produced cannot get to the surface of the skin to evaporate. This causes inflammation that results in a rash.
Common symptoms of heat rash include red bumps on the skin, and a prickly or itchy feeling to the skin (also known as prickly heat).
The rash appears as reddened skin with tiny blisters and is due to inflammation. It often occurs in skin creases or areas of tight clothing where air cannot circulate.
Heat rash usually fades when the skin is allowed to cool. Medical treatment is necessary only if the area becomes infected.
Heat rash can be prevented by avoiding hot, humid conditions, wearing lose fitting clothes, and using air conditioning or fans to allow air to circulate.
What is heat rash?
The skin’s job is to protect the inside of the body from the outside world. It acts as a preventive barrier against intruders that cause infection, chemicals, or ultraviolet light from invading or damaging the body. It also plays an important role in the body’s temperature control. One way that the body cools itself is by sweating and allowing that sweat or perspiration to evaporate. Sweat is manufactured in sweat glands that line the entire body (except for a few small spots like fingernails, toenails, and the ear canal).
Sweat glands are located in the dermis or deep layer of the skin and are regulated by the temperature control centers in the brain. Sweat from the gland gets to the surface of the skin by a duct.
A heat rash occurs when sweat ducts become clogged and the sweat cannot get to the surface of the skin. Instead, it becomes trapped beneath the skin’s surface causing a mild inflammation or rash.
Heat rash is also called prickly heat or miliaria.
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 efficiently 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.
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 cannot complain about the rash sensation, he or she may be fussy.
Who is at risk for heat rash?
Newborns, infants, the elderly, and obese individuals with large areas with skin-on-skin contact areas (for example, a large overlapping area of abdominal fat) are at risk for developing heat rash. They all are especially at risk if they are immobile for long periods and parts of the skin aren’t exposed to circulating air, which results in the inability of the sweat ducts to “breathe” (evaporative cooling).
What does heat rash look like?
The appearance of the heat rash depends upon where the excess sweat is deposited in the skin.
Tiny blisters that look like small beads of sweat are seen if the sweat is blocked at the most superficial layers of the skin where the sweat duct opens on the skin surface. Called miliaria crystallina, it has no symptoms other than these “sweat bubbles.
“Classic heat rash or miliaria rubra occurs if the sweat causes inflammation in the deeper layers of the epidermis. Like any other inflammation, the area becomes red (and therefore the name rubra = red) and the blisters become slightly larger. Because the sweat ducts are blocked and don’t deliver sweat to the skin’s surface, the area involved is dry and can be irritated, itchy, and sore. This rash is also called prickly heat.
Less commonly, after repeated episodes of prickly heat, the heat rash may inflame the deeper layer of the skin called the dermis, and cause miliaria profunda. This rash is made up of larger, harder bumps that are more skin-colored. The rash begins almost immediately after exercise, and again no sweat can be found on the affected areas. Rarely, this type of heat rash may be potentially dangerous if enough skin is involved, since the lack of sweating can lead to heat-related illnesses like heat cramps, heat exhaustion, or heat stroke.
How is heat rash diagnosed?
The diagnosis of heat rash is made by physical examination. Knowing that the rash appears during sweating or heat, appreciating the location on the body (in skin creases or where clothes fit tightly) and seeing what the rash looks like is enough to make the diagnosis. As with many rashes, the health care professional may look at the involved skin and because of previous experience, immediately make the diagnosis.
What is the treatment for heat rash?
Treatment for heat rash include home remedies such as over-the-counter creams and sprays. Medical treatment for heat rash may involve antibiotics if the sweat glands become infected.
Home remedies for heat rash. Heat rash often resolves on its own when the skin cools. If the prickly sensation persists, calamine lotion may be helpful. Some clinicians also recommend over-the-counter hydrocortisone creams or sprays.
Medical treatment for heat rash.
Heat rash resolves on its own once the skin cools, but on occasion, the sweat glands can become infected. The signs of infection include pain, increased swelling, and redness that does not resolve. Pustules may form at the site of the rash. This infection occurs because bacteria have invaded the blocked sweat gland. Antibiotic treatment may be required. Chronic and recurrent heat rash may need to be treated by a health care professional or dermatologist (skin specialist).
How can heat rash be prevented?
Prevention is the most important treatment for heat rash. By allowing the skin to be exposed to circulating air, the potential for sweat ducts to become blocked and the glands to become inflamed decreases.
Other strategies to prevent heat rash include:
▪️Avoid exercising in hot, humid weather.
▪️ Wear loose clothing made of breathable fabrics like cotton.
▪️ Use air conditioning.
▪️ Keep the skin clean with frequent baths or showers to prevent sweat glands from becoming clogged.
▪️ Reduce the amount of overlapping skin-on-skin (fat or weight loss).
“Heat Rash: Pictures, Symptoms, and Treatment” ، medicinenet