Heat Rash: Causes, Symptoms, and First Aid Care

Heat rash is a skin condition that appears as a red or pink rash on areas of the body covered by clothing. It develops when sweat ducts become blocked, trapping sweat beneath the skin. This can lead to swelling, itchiness, and discomfort.

Heat rash is common in infants and young children, but it can also affect adults during hot, humid weather, including Canadian summer heat waves.

What Causes Heat Rash?

In infants and children, heat rash often develops when:

• They are overdressed for the temperature

• They are exposed to hot or humid environments

• Clothing traps sweat against the skin

A helpful guideline is to dress infants the same way an adult would dress comfortably at the same temperature and activity level. Cool hands or feet do not necessarily mean a child needs more clothing in warm weather.

Signs and Symptoms of Heat Rash

Heat rash usually appears as:

• Tiny red or pink bumps or pimples
• Mild swelling or skin irritation
• Itchiness or discomfort

In infants and young children, heat rash commonly develops on:

• Neck
• Head and scalp
• Shoulders
• Skin folds

Scratching or friction from clothing may worsen irritation. In rare cases, secondary skin infection may occur.

When to Monitor for Infection

Seek medical advice if the rash does not improve within 3–4 days, worsens, or if the child develops a fever.

Watch for signs of infection, including:

• Increasing pain, redness, swelling, or warmth
• Pus or drainage from the rash
• Red streaks spreading from the area
• Fever of 38°C or higher
• Swollen lymph nodes in the neck, armpits, or groin

If any of these occur, consult a healthcare professional promptly.

First Aid Management for Heat Rash

Most cases of heat rash resolve on their own with simple first aid care:

• Move the child or individual to a cool, shaded area
• Remove or loosen tight or heavy clothing
• Allow the skin to air-dry naturally
• Keep the skin cool and dry

⚠️ Avoid using ointments, creams, or lotions unless advised by a healthcare provider, as they may block pores further and worsen symptoms.

Preventing Heat Rash

To help prevent future episodes:

• Dress children in lightweight, breathable clothing
• Keep indoor sleeping and play areas cool
• Avoid overdressing, especially during hot weather
• Gradually reintroduce warmth after the rash resolves so the skin can adapt

First Aid Education in Canada

Understanding heat rash and other heat-related conditions helps caregivers respond early and prevent complications. First aid training, including intermediate first aid which includes environmental emergency training, teaches how to:

• Recognize environmental illnesses
• Manage heat-related conditions
• Know when medical care is needed

Educational Disclaimer

This information is provided for educational purposes only and does not replace medical advice. Hands-on first aid training improves confidence and preparedness during environmental emergencies.