Heat rash is caused when sweat ducts become blocked or inflamed, preventing sweat from reaching the surface of the skin to evaporate. Instead, sweat is trapped beneath the skin, leading to irritation and the formation of bumps or a rash

. Key factors that cause this blockage or inflammation include:

• Hot and humid weather, which increases sweating and the likelihood of sweat duct clogging

• Physical activity that causes excessive sweating

• Immature or underdeveloped sweat ducts, especially in newborns and young children, making them more prone to heat rash

• Wearing tight or non-breathable clothing that traps sweat against the skin

• Prolonged bed rest or fever, which can increase sweating and reduce airflow around the skin

• Use of certain medications or medical conditions that affect sweating or skin integrity

The blocked sweat ducts cause sweat to flow backward into the skin layers, causing inflammation and irritation that manifest as itchy, prickly bumps or blisters on the skin

. In summary, heat rash results from sweat duct obstruction due to excessive sweating combined with factors that hinder sweat evaporation, such as heat, humidity, clothing, and immature sweat glands