Heat rash, usually referred to as prickly heat, is a superficial, inflammatory skin disease that arises in summer or in hot environments, and is one of the common dermatological diseases to which children and people who have been in hot, humid environments for a long time are susceptible. The disease is most likely to develop in the summer. Due to the relatively high temperature and humidity in summer, patients sweat excessively, which is not easily evaporated completely, and the dermal keratin layer is impregnated with sweat, resulting in narrowing or blockage of the ductal opening of the sweat glands, which ruptures due to increased internal pressure after sweat stagnation. Heat rash has certain precipitating factors and usually develops in a hot environment, usually in the folds of the body, such as the neck, armpits, lower back, buttocks, etc. It is manifested as a dense distribution of papules or non-inflammatory blisters, and the number of papules increases significantly after sweating, but the conscious symptoms are not obvious and can gradually improve after the weather turns cool, so the clinical diagnosis is not difficult. If a heat rash appears, it can be treated promptly. In summer, cooling down by blowing air conditioners and fans, bathing with warm water every day, and keeping the skin dry, wearing comfortable and breathable cotton clothes, and applying prickly heat powder topically can usually relieve it.