Heat Rash

A heat rash is an area of your skin that becomes irritated because of sweat trapped in the pores and pathways (ducts) underneath your skin. As sweat can’t leave your body, a rash forms with tiny pimples or blisters.

Heat rashes are common in hot and humid climates. The rash most often develops areas of your body that don’t get enough airflow or areas where there’s skin-to-skin contact.

What are other names for a heat rash?

Heat rashes are also called:

• Prickly heat rash.
• Sweat rash.
• Miliaria.

Who does a heat rash affect?

A heat rash can affect anyone at any age. Babies, infants and toddlers have a higher risk because their glands and ducts are still growing. They’re also usually well-bundled or in multiple layers of clothing. Sweat causes heat rashes, so people who live in warm and humid climates or athletes are at a high risk as well. Heat rashes can affect people on bedrest when their clothing sits between their skin and another surface for a long period. Fever during an illness may also induce a heat rash.

How common are heat rashes?

Heat rashes affect an estimated 4% to 9% of newborns between 1 and 3 weeks of age. The condition also affects nearly 30% of adults who live in humid climates.