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Symptoms and Signs of Heat Rash

Doctor's Notes on Heat Rash Symptoms, Causes, Pictures, Remedies, and Treatment

Heat rash is a rash that breaks out when a person is overheated in warm conditions. The cause of heat rash is blockage of the sweat glands within the skin, which means that sweat cannot get to the skin surface to evaporate. Inflammation results, and this leads to a characteristic skin rash.  Blockage of the sweat glands can occur from heavy or tight clothing, areas of skin that rubs against adjacent skin (such as armpits or groin), heavy creams or lotions, or adhesive bandages.

The typical symptoms of heat rash are a bumpy, red, itchy skin rash, as well as a burning sensation or prickly feelings. Areas of the body commonly exposed to the sun like the hands, face, and neck are common locations for heat rash. Associated symptoms can include bumps on the skin that look like tiny blisters.

Medical Author:
Medically Reviewed on 3/11/2019

Heat Rash Symptoms, Causes, Pictures, Remedies, and Treatment Symptoms

Heat rash usually appears as very small pinpoint bumps at the entrances to sweat glands. In some areas, there may be red or pink patches of skin. More advanced heat rash may have greater degrees of irritation and large welts, and raised red bumps. Some people with heat rash are very itchy while others may have no irritating symptoms.

Any body part with sweat glands may be affected. Characteristic heat rash areas include the:

  • Face
  • Neck
  • Back
  • Abdomen
  • Groin
  • Under the breasts
  • Elbow folds
  • Buttocks

Home remedies for treating heat rash include washing the affected area with a mild soap and rinsing the area, then gently dry the area. Wear clothing that allows the skin to breathe in a hot environment. Stay hydrated and drink plenty of water to prevent dehydration in hot environments. Medical care may be necessary if the heat rash does not resolve with home remedies.

Most heat rash resolves without treatment, often within a day after changing to a cooler environment. The best way to prevent heat rash is to avoid sweating by staying in cooler areas, using fans, and limiting physical activity.

The following self-care steps and remedies may help with heat rash.

First aid

The first step in treating heat rash is to wash the affected area with a gentle soap (for example, Dove non-soap cleanser or something similar). Next, rinse the area with water and gently pat dry with a towel. It is recommended to wash several times a day, especially after exercise, prolonged walking, or heat exposure.

  1. Remain in a cool environment and allow for adequate ventilation of the skin.
  2. Take cool showers or baths
  3. Rest in an air-conditioned room at 70 F to 72 F (21 C to 22 C) is therapeutic. If no air conditioning is available at home, safe retreats include indoor shopping malls, grocery stores, movie theaters, hotel lobbies, ice-skating rinks, bowling alleys, etc.
  4. Avoid skin-to-skin contact by placing a clean cotton washcloth or material between skin folds like under the breasts or abdomen.
  5. Apply cool packs over the affected areas (do not leave packs on longer than 20 minutes per hour).
  6. Mild cortisone creams like hydrocortisone (Cortaid) or prescription cortisone creams like triamcinolone (Triesence, Trivaris Intravitreal) may be helpful for resistant rashes or resulting eczema. If it is necessary, apply these creams twice daily. For large areas, you should contact your healthcare professional.
  7. Oral antihistamines, such as diphenhydramine (Benadryl), can help decrease itching, mostly through the sedation associated with these medications.

Clothing and Heat Rash

Getting naked may keep the body cooler but it does not avoid the problem of sweat buildup especially under the breasts, abdomen fold, between buttock folds, and places where skin overhangs. It may be best to wear light, cotton, absorbent fabrics that separate out skin fold areas. Individuals who do not wear underwear usually notice more retained sweat and therefore more irritation in areas between the buttocks and groin. Short sleeves tops and shorts are often helpful.

Drinking Water

  1. Drink plenty of water for overall hydration.
  2. Water can help maintain cooler body temperatures.
  3. Dehydration may lead to weakness and generalized malaise.

Heat Rash Symptoms, Causes, Pictures, Remedies, and Treatment Causes

Most people with a heat rash it usually goes away seeing your doctor.

Persistent heat rash is typically diagnosed from the characteristic skin appearance on the exam and a history of recent heat exposure.

Atypical or more resistant cases of heat rash may require skin culture, a microscopic exam from skin scrapings, or less commonly a skin biopsy (surgically removing a very  small piece of skin using a local numbing agen. This skin is sent to a pathologist for closer examination.

Additional tests may be required to exclude other causes of skin rashes, for example:

Heat rash, or prickly heat, is thought to arise from plugging of sweat ducts and hair follicles on the skin. Occluded sweat glands with trapped sweat give rise to the tiny water bumps seen in this condition. Human sweat (with its high salt content) is a very potent skin irritant and may cause skin rashes. It is important to wash off sweat with gentle soap and water.

Heat Rash Pictures, Symptoms, Causes, & Treatments Slideshow

Heat Rash Pictures, Symptoms, Causes, & Treatments Slideshow

Your skin is your first line of defense from the outside world. It protects you from infections, chemical exposures, and harmful ultraviolet light. It also helps regulate the temperature inside your body by producing sweat. Sweat on your skin comes from sweat glands located all over your body (except in your fingers, toenails, and ear canals). These small glands are regulated by the brain and produce sweat that comes to the surface via ducts on your skin, which then evaporates and helps cool you down.


Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.