Acne under the neck is actually acne in the neck area. Acne, as a follicular sebaceous gland related disease, is commonly caused by: 1) blockage of follicular sebaceous gland openings; 2) infection by Propionibacterium acnes; 3) endocrine factors, especially abnormal androgen levels in the body; 4) involvement of inflammatory factors, etc. It is a multifactorial disease. Of course there is also a relationship with diet, such as spicy and stimulating, fried and greasy food or staying up late. From a clinical point of view, in addition to the above factors, acne on the bottom of the neck, there may also be a certain relationship with the friction stimulation of the neck by wearing clothes or scarves, etc. So the neck acne is a multi-factorial disease, to specific analysis, may be the result of a combination of one or several factors above.