What is Heat Rash

Heat rash is an itchy rash of little red bumps that often occurs during hot, humid weather. Heat rash is also called prickly heat or miliaria.

Heat rash usually affects:

• Armpits.
• Elbows.
• Groin.
• Neck.
• The area underneath the breasts.
• Shoulders.
• Chest.

What are the causes?

This condition is caused by blocked sweat ducts. When sweat is trapped under the skin, it spreads into surrounding tissues and causes a rash of red bumps.

What increases the risk?

This condition is more likely to develop in people who:

• Are overdressed in hot, humid weather.
• Wear clothing that rubs against the skin.
• Are active in hot, humid weather.
• Sweat a lot.
• Are not used to hot, humid weather.

What are the signs or symptoms?

Symptoms of this condition include:

• Small red bumps that are itchy or prickly.
• Very little sweating or no sweating in the affected area.

How is this diagnosed?

This condition is diagnosed based on your symptoms and medical history, as well as a physical exam.

How is this treated?

Moving to a cool, dry place is the best treatment for heat rash. Treatment may also include medicines, such as:

• Corticosteroid creams for skin irritation.
• Antibiotic medicines, if the rash becomes infected.

Follow these instructions at home:

Skin care

• Keep the affected area dry.
• Do not apply ointments or creams that contain mineral oil or petroleum ingredients to your skin. These can make the condition worse.
• Apply cool compresses to the affected areas.
• Do not scratch your skin.
• Do not take hot showers or baths.

General instructions

• Take over-the-counter and prescription medicines only as told by your health care provider.
• If you were prescribed an antibiotic, take it as told by your health care provider. Do not stop taking it even if your condition improves.
• Stay in a cool room as much as possible. Use an air conditioner or fan, if possible.
• Do not wear tight clothes. Wear comfortable, loose-fitting clothing.
• Keep all follow-up visits as told by your health care provider. This is important.

Contact a health care provider if:

• You have a fever.
• Your rash does not go away after 3–4 days.
• Your rash gets worse or it is very itchy.
• Your rash has pus or fluid coming from it.

Get help right away if:

• You are dizzy or nauseated.
• You feel confused.
• You have trouble breathing.
• You have chest pain.
• You have muscle cramps or contractions.
• You faint.

Summary

• Heat rash is an itchy rash of little red bumps that often occurs during hot, humid weather.
• Symptoms of heat rash include small red bumps that are itchy or prickly and very little or no sweating in the affected area.
• This condition is diagnosed based on your symptoms and medical history, as well as a physical exam.
• Moving to a cool, dry place is the best treatment for heat rash.
• Do not wear tight clothes. Wear comfortable, loose-fitting clothing.