What Is Heat Rash?

Heat rash occurs when tiny sweat ducts — the channels that carry sweat to the surface of the skin — become blocked. When sweat is trapped under the skin instead of evaporating, small red or pink bumps can appear. These bumps may be accompanied by mild itching or irritation.

Babies are especially prone to heat rash because:

• Their sweat glands are still developing
• Their skin is thinner and more sensitive
• They can easily become overheated from warm weather, multiple layers of clothing, or prolonged time in a hot environment

Even everyday situations, like a nap in a warm room or sitting in a car seat for too long, can contribute to the condition.