Acne under the neck is actually acne on the neck. Acne, as a hair follicle sebaceous gland related disease, its common reasons are: 1. The opening of the hair follicle sebaceous gland is blocked. 2. Propionibacterium acnes infection. 3. Endocrine factors, especially the level of androgen in the body are abnormal. 4. Inflammatory factors are involved, which is a multifactorial disease. Of course, it also has something to do with food, such as spicy, fried, greasy food or staying up late. Clinically, in addition to the above factors, acne under the neck may also be related to the wear of clothes or scarves that irritate the neck. Therefore, acne on the neck is a multifactorial disease. It may be the result of one or more of the above factors.