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Definition

What is heat rash?

Heat rash or miliaria is a common condition, which occurs in hot, humid weather. It isn’t usually painful, but it can be annoyingly itchy. The intense prickling or stinging sensation may be distressing. Some of the pimples may also be tender to the touch.
Heat rash usually heals without treatment. However, the severe infection forms of heat rash may need medical care, so the best way to relieve symptoms is to cool your skin and prevent sweating.

How common is heat rash?

This health condition is extremely common. It commonly affects infants. It can affect patients at any age. It can be managed by reducing your risk factors. Please discuss with your doctor for further information.

Symptoms

What are the symptoms of heat rash?

The common symptoms of heat rash are irritating tiny pimples form on the head, neck, and shoulder. The rash areas can get irritated by clothing or scratching, and, in rare cases, a secondary skin infection may develop.

The types of miliaria are classified according to how deep are the blocked sweat ducts. There are some signs and symptoms for each type.

  • Miliaria crystalline. The mildest form of heat rash affects the sweat ducts in the top layer of skin. This form is marked by clear, fluid-filled blisters, and bumps (papules) that break easily.
  • Miliaria rubra also known as prickly heat. A type that occurs deeper in the skin. Signs and symptoms include red bumps and itching or prickling in the affected area.
  • Miliaria pustulosa. This form is the inflammation of the fluid-containing sacs (vesicles).
  • Miliaria profunda. This less common form of heat rash affects the dermis, a deeper layer of skin. Retained sweat leaks out of the sweat gland into the skin, causing the firm, flesh-colored lesions that resemble goose bumps.

There may be some symptoms not listed above. If you have any concerns about a symptom, please consult your doctor.

When should I see my doctor?

You should contact your doctor if you have any of the following:

  • Increased pain, swelling, redness or warmth around the affected area.
  • Red streaks extending from the affected area.
  • Drainage of pus from the area.
  • Swollen lymph nodes in the armpit, neck or groin.
  • Fever of  38°C or higher, or chills with no other known cause.

Causes

What causes heat rash?

Heat rash develops when some of your sweat ducts clog. It’s not always clear why the sweat ducts become blocked, but certain factors seem to play a role, including:

  • Immature sweat ducts. Heat rash can develop in the first week of life, especially if the infant is being warmed in an incubator, is dressed too warmly or has a fever.
  • Hot, humid weather.
  • Sweaty activities.
  • Overheating.
  • Prolonged bed rest.

Risk factors

What increases my risk for heat rash?

There are many risk factors for heat rash, such as:

  • Newborns are most susceptible.
  • Tropical climates. People living in the tropics are far more likely to have heat rash than are people in temperate climates.
  • Physical activity. Anything that makes you sweat heavily, especially if you’re not wearing clothing that allows the sweat to evaporate, can trigger a heat rash.

Diagnosis & treatment

The information provided is not a substitute for any medical advice. ALWAYS consult with your doctor for more information.

How is heat rash diagnosed?

Your doctor diagnoses it by its appearance, it does not usually require medical attention.

How is heat rash treated?

In most cases, heat rash will clear up on its own in a few days. Severe forms of heat rash may require ointments that you apply to your skin to relieve discomfort and prevent complications. Such topical treatments may include calamine lotion, anhydrous lanolin, topical steroids.

Lifestyle changes & home remedies

What are some lifestyle changes or home remedies that can help me manage heat rash?

The following lifestyles and home remedies might help you cope with heat rash:

  • Wear loose cotton clothing, lightweight clothing that wicks moisture away from your skin.
  • Spend as much time as possible in air-conditioned buildings.
  • Let the skin air-dry instead of using towels.
  • Bathe or shower in cool water with nondrying soap, then let your skin air-dry instead of toweling off.
  • Use calamine lotion or cool compresses to calm itchy, irritated skin.
  • Avoid using creams and ointments that contain petroleum or mineral oil, which can block pores further.
  • Using an antibacterial soap or antiseptic wash may help to keep the number bacteria on your skin down.
  • A steroid cream may soothe the irritation whilst you are waiting for the condition to clear. A mild steroid cream such as hydrocortisone1% can be purchased over the counter. You should not use it on your face. Follow the instructions, and use it sparingly.

If you have any questions, please consult with your doctor to better understand the best solution for you.

Hello Health Group does not provide medical advice, diagnosis or treatment.

Review Date: January 4, 2017 | Last Modified: January 4, 2017

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