Heat Rash Overview

Macro shot of a skin rash.
Heat rash is typically caused by blocked sweat ducts. See more pictures of skin problems.

Most people love being outside when the weather is hot. We have barbecues, go to the beach, ride our bikes and take long walks. But all this outdoor activity puts us at a greater risk for developing a condition known as heat rash -- a skin irritation caused by blocked sweat ducts. Heat rash usually develops in hot or humid weather, when people overheat and sweat profusely. It appears as a patch of small pink or red bumps on the skin and most commonly occurs on areas of the body covered by clothing. As people perspire, sweat ducts on the skin can become blocked. Clothing can uncomfortably rub against the skin, causing friction and irritation.

Heat rash is most common in infants [source: FamilyDoctor]. It tends to happen when parents overdress their children, particularly in hot weather. People can avoid heat rash by dressing in lightweight, loose-fitting, light-colored clothing and staying out of the sun on particularly hot and humid days. Parents can prevent their children from getting heat rash by not over-dressing them. Children should be dressed in clothes similar to what the parents would find comfortable for a hot day.


Typically, medical attention is not necessary unless the heat rash seems to be getting worse or persists for an extended period of time [source: FamilyDoctor]. If there are signs of an infection, such as fever or inflammation of the affected area, you should contact your doctor immediately. If the rash is severe, a doctor may find it necessary to prescribe certain medications. In most cases, however, heat rash will heal itself in a few days.

Although the rash will likely be gone in a few days, you will still need to contend with the itching and discomfort. We will cover routine treatments and natural remedies for this later in this article. But really, the best thing to do would be to avoid the problem entirely. To learn how to do this, keep reading to find out more about the causes of heat rash.


Heat Rash Causes

Most common in babies, heat rash can affect anyone during hot and humid weather. When people perspire, sometimes their sweat ducts become blocked, and an annoying cluster of pink or red bumps appears on their skin. This is heat rash. It usually affects areas of the skin covered by clothing, where the fabric can become sweaty and rub against the skin. Heat rash is irritating and itchy and can sometimes develop into a more serious infection. However, in most cases, it will heal on its own [source: Peoples-Health].

Heat rash may look like nothing more than a bunch of small, red bumps or pimples. In adults, it usually appears in the folds of the skin, while in babies, it typically develops on the head, neck or shoulders. Heat rash in children tends to occur when parents unintentionally overdress them when the weather is hot. It may seem like children require more protective clothing than adults do, especially on hot summer days, but parents should always dress their children in the same types of clothing they would dress themselves.


Heat rash typically affects babies because their sweat ducts are not developed enough to adequately release perspiration. Adults can develop heat rash during any intense physical activity that causes them to perspire a lot. Certain bacteria on the skin can plug sweat ducts as well, causing irritation. Even some medications, such as diuretics and those used for the treatment of Parkinson's disease, have been found to increase the occurrence of heat rash [source: MedicineNet].

Heat rash will most often disappear on its own after three or four days. Of course, it will be incredibly itchy and annoying during this time. If the heat rash seems to be developing into a more serious infection, contact your doctor.

Possible signs of an infection include:

  • A fever of 100 degrees Fahrenheit (37.8 degrees Celsius) or higher
  • Inflammation of the irritated area
  • The development of pus
  • A swelling of the lymph nodes in the neck, armpit or groin

[source: WebMD]

For the most part, heat rash tends to be more annoying than it is harmful (unless the victim is also developing heat exhaustion -- more on that later). During the long, dog days of summer, it can be practically unavoidable. If you find yourself afflicted, you'll want to know how to treat the symptoms until it has time to heal. Go to the next page to learn about treatments for heat rash.


Heat Rash Treatments

Most people develop heat rash in hot and humid weather when they are outside and perspiring profusely. The tiny red blisters that appear on the skin itch and burn, and clothing can irritate the area even more.

There are several treatment options available to ease the irritation. Applying calamine lotion on the affected area can help relieve itching and burning. Aloe vera gel is another good way to soothe heat rash, but keep in mind that too much of these or any other lotions or ointments can further exacerbate the rash by maintaining moisture. Try to avoid rubbing or scratching the rash as much as possible. A doctor may prescribe anhydrous lanolin in more serious cases, which stops sweat ducts from becoming blocked. The doctor might also prescribe steroids to treat the area if the heat rash is severe [source: Mayo Clinic].


It's important to note that people with severe heat rash are often also at risk for developing heat exhaustion. Symptoms of heat exhaustion include dizziness, low blood pressure, increased heart rate, nausea and headache. People with heat exhaustion should seek medical attention immediately because it can lead to a more serious condition known as heatstroke -- a potentially life-threatening illness [source: Mayo Clinic].

To help ease the discomfort of heat rash among children, let them sit in a lukewarm or cool bath. Afterward, air-dry their skin and refrain from applying creams or heavy lotions. Limit diaper use as much as possible. Dress them in loose-fitting, lightweight, light-colored, soft clothing. For infants and toddlers, it might be helpful to trim their fingernails or place mittens or socks over their hands to prevent them from scratching the affected areas [source: BabyCenter]. Keep children indoors, in a cool or air-conditioned area until the heat rash heals. Be sure to monitor the rash closely for any signs of infection. If signs of infection do occur, such as fever or inflammation, contact a physician immediately.

Continue reading to find out about natural treatments and tips for relieving heat rash.


Natural Heat Rash Treatments

You can avoid heat rash by staying inside, but if you just have to head outside into the heat, you'll want to be prepared to treat your heat rash. But what if you don't have calamine lotion or aloe vera gel, and the thought of heading out in the sweltering heat to the pharmacy for supplies is unbearable? Luckily, there are some things you can do at home to ease irritation of the affected area. Surprisingly, something as simple as a cool bath can help soothe and cool your skin. But since you can't sit in the bath all day, you'll need to know what to do beyond the tub. First, try to dress in loose-fitting, lightweight, light-colored, soft clothing that will not rub against and irritate your skin. Until the heat rash clears, it is best to avoid going outside in hot and humid weather. Stay in shaded places or air-conditioned buildings, and when you take those nice cold baths, air-dry your skin or very gently pat it dry instead of rubbing it dry with a towel, which can cause additional irritation [source: eMedicineHealth].

The bumps and blisters that develop from heat rash can cause a lot of discomfort. Gently applying ice, either directly or wrapped in a soft cloth, on the area is one way you can help to relieve the burning and itching sensation. You can increase your bath's effectiveness by combining a cup or two of oatmeal with a few teaspoons of baking soda and pouring it in your tub. Or you can lightly dust the affected area with baby powder (a mild, unscented powder is best) or cornstarch to keep it dry and cool.


If the heat rash seems to be getting worse, be sure to contact your doctor. Otherwise, the best way to beat the heat -- and the heat rash -- is simply to stay cool.

To learn more, look over the links on the next page.


Lots More Information

Related HowStuffWorks Articles

  • Alai, Nili N., MD, FAAD. "Heat Rash." eMedicineHealth. (8/11/09). http://www.emedicinehealth.com/heat_rash/article_em.htm#Overview
  • BabyCenter. "Heat Rash." (8/11/09).http://www.babycenter.com/0_heat-rash_10881.bc?page=1
  • FamilyDoctor. "Heat Rash." FamilyDoctor.org. (8/11/2009). http://familydoctor.org/online/famdocen/home/common/skin/disorders/921.html
  • Mayo Clinic. "Heat Rash." (8/3/09).http://www.mayoclinic.com/health/heat-rash/DS01058
  • MedicineNet. "Heat Rash." (8/11/09).http://www.medicinenet.com/heat_rash/article.htm
  • Peoples-Health. "Causes, Symptoms, and Treatments of Heat Rash." (8/11/09).http://www.peoples-health.com/causes-symptoms-treatment.html
  • WebMD. "Heat Rash -- Topic Overview." (8/3/09).http://www.webmd.com/skin-problems-and-treatments/tc/heat-rash-topic-overview