Heat rash is a skin condition that develops in hot, humid environments. It causes small discolored or fluid-filled blisters to develop in the folds of your skin or areas where clothing rubs the skin.

When this happens, it causes a condition called psoriatic arthritis that ... sweat to pool up in your skin, TODAY.com ...

Sweat is unable to get through the pores of the skin, which becomes irritated and causes a rash to develop. There are different severities of heat rash. The mildest and most common types look like ...