The Skin Center

26081 Merit Circle Suite #109
Laguna Hills, CA 92653
(949- 582-7699
(949) 582-SKIN
Fax (949) 582-7691

Diplomat, American Board of Dermatology
Fellow, American Society of Mohs Surgery
Fellow, American Academy of Dermatology
Expert Reviewer, Medical Board of California
Former Professor University of California Irvine 

An interview with our Doctors: The Skin Center at Laguna

Heat Rash

What is Heat Rash?

 Heat Rash is the generic group name for a number of skin problems that arise or worsen because of heat exposure or overheating. Common names for heat rash include prickly heat or miliaria. Other heat rashes include heat urticaria (hives) and sweat retention.  Heat rash is prevalent in the summer months and particularly in humid climates. The condition usually is self-limited and resolves in hours to a few days without treatment. Rare cases may be more severe requiring medical care.


What is Miliaria?

Miliaria is the medical term for the heat related skin condition where tiny, pinpoint, pink to clear bumps form over a body area like the face or neck. It is caused when small sweat particles are trapped in the skin. This trapping of sweat may cause inflammation and itching around the sweat pores. Miliaria is very common in infants but may also occur in adults. This condition occurs especially after repeated episodes of sweating in a hot, humid environment.

There are 4 types of miliaria including a clear version (miliaria crystalline), a white/yellow type (miliaria pustulosa), a red type (miliaria rubra), and a deep kind (miliaria profunda). Miliaria may look like small clear blisters or like gooseflesh.


Who is at risk?

Anyone can develop heat rash especially when in the right environment. Some individuals are more prone to this condition including:

  • Babies
  • Children under age 4
  • Athletes
  • Obese or overweight persons
  • Bedridden and non-ambulatory patients
  • Individuals with congenital absence or decreased sweating
  • Military troops


What areas are commonly affected?

Any body part may be affected. Characteristic areas include the face, neck, back, abdomen, groin, under breasts, elbow folds, and buttocks.


What causes it?

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. In general, 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.


What does it look like?

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


How is Heat Rash treated?

  • Most cases resolve without treatment. Other cases resolve within a day after moving to a cooler environment.
  • It is helpful to remain cool and allow for good ventilation of the skin.
  • Cool showers or baths are very helpful.
  • Resting in an air-conditioned room at 70-72 degrees 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, and many other options.
  • A very good starting point for heat rash is washing the affected area with a gentle soap like Dove non-soap cleanser. Then rinse the area with water and gently pat dry with a towel. Washing several times a day and especially after exercise, prolonged walking, or heat exposure is recommended.
  • Avoid skin-to-skin contact by placing a clean cotton washcloth or material between skin folds like under the breasts or abdomen.
  • Direct applications of packs of frozen peas or cool packs are helpful.
  • Mild cortisone creams like hydrocortisone (Cortaid) or prescription cortisone creams like triamcinolone may be helpful for resistant rashes or resulting eczema.
  • Oral or topical antibiotics may be prescribed as needed for bacterial infections.
  • Oral antihistamines like Benadryl or Claritin help decrease itching.


Should I take off all of my clothes when I am at home?

Getting naked may keep you 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.


How can I prevent Heat Rash?

  • Wear cool breathable fabrics like cotton. Avoid polyesters and nylon.  Maintain a comfortable room temperature with fans and air conditioning.
  • Babies should be kept comfortably cool and dry. Because of babies’ increased fat folds and diaper irritation, they frequently get rashes on their diaper area and abdomen folds. Typical infant drooling may cause further occlusion and heat rash on the face cheeks.
  • Bedridden and wheelchair bound patients should be rotated and moved to avoid constant sweating and occlusion in the same area.


What makes Heat Rash or Prickly Heat worse?

  • High humidity
  • High temperatures
  • Jacuzzis, saunas, and steam rooms
  • Fever
  • Sunburn
  • Regular sweating or hyperhidrosis (excess sweating)
  • Tight garments and non-breathable fabrics
  • Application of perfumes, body oils, fragranced lotions and creams (may cause secondary irritation and allergic dermatitis)


Can it lead to heat stroke?

 While heat rash does not lead to heat stroke, both conditions may rarely occur in the same individual. Heat rash is a very common, self-limited skin condition while heat stroke is an uncommon more serious, generalized illness. Heat stroke requires immediate medical attention. Heat stroke is particularly life threatening in the frail, ill, and elderly.


When do I need to see my doctor?

 If your rash is not going away with home treatment above or getting worse after 3-5 days you should see your physician to make sure there is not a bacterial infection or other cause. If you have fever, headaches, nausea, dizziness, or vomiting, you should immediately seek medical help.


Does drinking water help?

 Water is always helpful for overall hydration and body temperature regulation. Water can help maintain cooler body temperatures. Dehydration may lead to weakness and generalized malaise. It is not certain if drinking water specifically helps in treating the symptoms of heat rash.


What else could it be?

 Many other rashes can look like Heat Rash. Some of these other conditions include:

  • Folliculitus (a bacterial infection of the skin commonly with “staph”)
  • Acne
  • Eczema
  • Allergic rash
  • Medication reaction or drug eruption
  • Grover’s disease (also called transient acantholytic dermatosis-causes itchy bumps on the abdomen and chest that worsen with heat)
  • Niacin pills (in some individuals, cause a temporary overall body flushing and heat rash like appearance that improves in a few hours)


Heat Rash Do’s:

  • Do get out of the heat.
  • Do wear cool, breathable fabrics like cotton.
  • Do maintain comfortable temperatures with fans and air conditioning.
  • Do wash off the skin with Dove soap and pat dry after sweating or exercise.
  • Do take a cool shower or bath.
  • Do seek immediate medical attention for signs of heat stroke.


Heat Rash Don’ts:

  • Don’t wear polyesters and nylon in the summer.
  • Don’t cover with ointments, Vaseline, or heavy creams.
  • Don’t scrub or rub the skin to remove heat rash bumps.
  • Don’t stay in the heat or humidity.
  • Don’t go in the hot tub, sauna, or Jacuzzi. 


Call to Schedule an appointment at (949) 582-SKIN 


Dr. Gary Cole and Dr. Nili Alai are Board-Certified Dermatologists.
For more information, please call (949) 582-7699 or visit the practice website at




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