Heat Rash: Heat and Sweat Can Disrupt the Skin's Balance

The human body has millions of sweat glands that help regulate body temperature through evaporative cooling. However, if the fine excretory ducts of the sweat glands can no longer adequately drain the sweat, the fluid accumulates under the skin, resulting in small blisters or nodules that can cause varying degrees of itching or burning, depending on the type of heat rash. Areas of the skin where heat and moisture build up are particularly affected. 

Among the most common triggers are:

• high outdoor temperatures
• high humidity
• intense physical activity
• tight clothing
• fabrics that don’t breathe well
• prolonged bed rest with heavy sweating
• Fever

Babies develop heat rash more quickly because their sweat glands are not yet fully developed. 

Symptoms usually appear suddenly and often affect areas of the body where sweat accumulates particularly easily. Skin changes are most commonly seen on the neck, chest, back, in the armpits, or in skin folds.

Typical symptoms include:

• small red blisters
• fine nodules
• Itching
• a burning sensation on the skin
• reddened skin
• Mild stinging
• Sensation of warmth

Reddened skin or itchy blisters can have many causes. Allergies, atopic dermatitis, fungal infections, or bacterial skin infections may also be potential triggers. If the symptoms persist for a long time, spread, or are accompanied by a fever or severe pain, the skin should be examined by a doctor to rule out other conditions. 

In most cases, the typical appearance of the skin and a description of the symptoms are sufficient. The doctor pays particular attention to the location of the rash and asks about exposure to heat, heavy sweating, or physical exertion. Further tests are usually not necessary. Additional tests may be warranted only if another skin condition is suspected. 

The most important measure is to keep the skin as cool and dry as possible. This allows the blocked sweat glands to open up again. Light, breathable clothing helps sweat evaporate. Cool showers or damp compresses can relieve the itching. For more severe symptoms, anti-itch lotions or, in certain cases, cortisone-based creams may be used. Scratching should be avoided as much as possible, as it can cause small skin abrasions through which pathogens can more easily enter the body. 

Especially on hot summer days, simple measures can significantly reduce the risk.

These include:

• wearing loose-fitting clothing made of breathable fabrics
• avoiding direct heat as much as possible
• regularly seeking out cool rooms
• drinking plenty of fluids
• changing out of sweaty clothes
• Keep your skin dry

For infants, it’s also essential to make sure they aren’t dressed too warmly. 

Although heat rash is usually harmless, it can cause severe itching and uncomfortable skin irritation. By avoiding heat as much as possible, wearing breathable clothing, and keeping the skin dry, you can often quickly relieve symptoms or effectively prevent them from recurring.