The main reason for the increase in acne after hot weather is that there is a significant increase in local sweating and sebaceous secretion, and if the patient has chronic inflammation, acne can be aggravated. However, patients must be aware that acne is not necessarily acne when the weather is hot. There are many other clinical conditions that can occur when the temperature rises and the incidence rises significantly. The first condition is folliculitis. When patients sweat more in the heat, they tend to scratch themselves, which can easily lead to bacterial infections in the hair follicles. Sometimes there is no way to distinguish folliculitis from acne, and patients may also develop Malassezia folliculitis on the jaw, which is often closely related to high temperatures, more sweating, and fungal infections.