Heat-Related Illness

  • Medical Author:
    Steven Doerr, MD

    Steven Doerr, MD, is a U.S. board-certified Emergency Medicine Physician. Dr. Doerr received his undergraduate degree in Spanish from the University of Colorado at Boulder. He graduated with his Medical Degree from the University Of Colorado Health Sciences Center in Denver, Colorado in 1998 and completed his residency training in Emergency Medicine from Denver Health Medical Center in Denver, Colorado in 2002, where he also served as Chief Resident.

  • Medical Editor: William C. Shiel Jr., MD, FACP, FACR
    William C. Shiel Jr., MD, FACP, FACR

    William C. Shiel Jr., MD, FACP, FACR

    Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

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Heat rash

Heat rash is a skin irritation that occurs in hot, humid weather. It is caused by profuse sweating, which can lead to the blockage of sweat ducts. It can occur at any age, but is most common in young children.

What are the signs and symptoms of heat rash?

Heat rash appears as a cluster of small red pimples or blisters. This skin irritation can be itchy. It typically occurs on the neck and upper chest, in the groin, under the breasts, and in the elbow creases.

Pictures of heat rash in children and adults
Pictures of heat rash in children and adults

What is the treatment for heat rash?

The best treatment for heat rash is to avoid a hot, humid environment and to try to remain in cooler, less humid conditions. Try to keep the affected area dry, and wear light, loose clothing. Dusting powder may be used to increase comfort, but avoid using ointments or creams because they keep the skin warm and moist and may make the condition worse.

Treating heat rash is simple and usually does not require medical assistance.

Heat-related illness prevention

To protect your health when temperatures are extremely high, remember to keep cool and use common sense. The following tips are important.

Drink plenty of fluids

Increase your fluid intake regardless of your activity level. Do not wait until you feel thirsty. During heavy exercise in a hot environment, drink 2-4 glasses (16-32 ounces) of cool fluids each hour.

Caution: If your doctor has prescribed a fluid-restricted diet or diuretics for you, ask your doctor how much you should drink.

  • During hot weather, you will need to drink more liquid than your thirst indicates. This is especially true for people 65 years of age and older who often have a decreased ability to respond to external temperature changes.
  • Drinking plenty of liquids during exercise is especially important. However, avoid very cold beverages because they can cause stomach cramps.
  • In addition, avoid drinks containing alcohol or caffeine, because they will actually cause you to lose more fluid.

Replace salt and minerals

Heavy sweating removes salt and minerals from the body. These are necessary for your body and must be replaced. The easiest and safest way to replace salt and minerals is through your diet.

  • Drink a sports beverage during exercise or work in the heat.
  • Do not take salt tablets unless directed by your doctor.
  • If you are on a low-salt diet, ask your doctor before changing what you eat or drink, especially before drinking sports beverages.

Wear appropriate clothing and sunscreen

  • Wear as little clothing as possible when you are at home. Choose lightweight, light-colored, loose-fitting clothing. In the hot sun, a wide-brimmed hat will provide shade and keep the head cool.
  • Sunburn affects the body's ability to cool itself and causes a loss of body fluids. It also causes pain and damages the skin.
  • A variety of sunscreens are available to reduce the risk of sunburn. The protection that they offer against sunburn varies. Check the sun protection factor (SPF) number on the label of the sunscreen container. Select SPF 15 or higher to protect yourself adequately. Apply sunscreen 30 minutes before going outdoors and reapply according to package directions.

Pace yourself

  • If you are unaccustomed to working or exercising in a hot environment, start slowly and pick up the pace gradually.
  • If exertion in the heat makes your heart pound and leaves you gasping for breath, STOP all activity. You should get into a cool area or in the shade, and rest, especially if you become lightheaded, weak, or faint.

Stay cool indoors

  • The most efficient way to beat the heat is to stay in a cool or air-conditioned area.
  • If you do not have an air conditioner or evaporative cooling unit, consider a visit to a shopping mall, see a movie in a movie theater, or visit a public library for a few hours.
  • Contact your local health department to see if there are any heat-relief shelters in your area.
  • Electric fans may be useful to increase comfort and to draw cool air into your home at night, but do not rely on a fan as your primary cooling device during a heat wave. When the temperature is in the 90s or higher, a fan will not prevent heat-related illness.
  • A cool shower or bath is a more effective way to cool off. Also, use your stove and oven less to maintain a cooler temperature in your home.

Schedule outdoor activities carefully

  • If you must be out in the heat, try to plan your activities so that you are outdoors either before noon or in the evening.
  • While outdoors, rest frequently in a shady area.
  • Resting periodically will give your body's thermostat a chance to recover.

Use a buddy system

  • When working in the heat, monitor the condition of your coworkers and have someone do the same for you. Heat-related illness can cause a person to become confused or lose consciousness.
  • During a heat wave, have a friend or relative call to check in on you twice a day if you are 65 years of age or older. If you know anyone in this age group, check on them at least twice a day.

Adjust to the environment

  • Be aware that any sudden change in temperature, such as an early summer heat wave, will be stressful to your body. You will have a greater tolerance for the heat if you limit your physical activity until you become accustomed to the heat.
  • If traveling to a hotter climate, allow several days to become acclimated before attempting any vigorous exercise, and work up to it gradually.

Use common sense

  • Avoid hot foods and heavy meals as they may add heat to your body.
  • Do not ever leave infants, children, or pets in a parked car.
  • Dress infants and young children in cool, loose clothing and shade their heads and faces with hats or an umbrella. Make sure they use sunscreen when outdoors.
  • Limit sun exposure during the mid-day hours and in places of potential heavy sun exposure, such as beaches.
  • Ensure that infants and children drink adequate amounts of liquids.
  • Make sure to keep your pet cool by giving them plenty of fresh water, and leave the water in a shady area.

One last hot tip

These self-help measures are not a substitute for medical care but may help you recognize and respond promptly to warning signs of trouble. Your best defense against heat-related illness is prevention. Staying cool and making simple changes in your fluid intake, activities, and clothing during hot weather can help you remain safe and healthy.

Medically reviewed by Avrom Simon, MD; Board Certified Preventative Medicine with Subspecialty in Occupational Medicine


Centers for Disease Control and Prevention. Extreme Heat. <http://emergency.cdc.gov/disasters/extremeheat/index.asp>

Medically Reviewed by a Doctor on 10/6/2016

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