Acne on the shoulders may be caused by folliculitis, acne, seborrheic dermatitis and other symptoms. 1. Folliculitis: often caused by excessive sweating or eating more spicy, greasy food, resulting in the secretion of a large number of sebaceous glands inside the hair follicles, blocking the pores, thus appearing in the case of acne. 2. Acne: a chronic inflammatory disease common in adolescents, which can be reduced or cured naturally after puberty. It mainly occurs in areas where sebaceous glands secrete abundantly, such as the face, chest and back, shoulders, etc., and is characterized by polymorphic lesions such as pimples, papules, pustules and nodules. 3. Seborrheic dermatitis: Seborrheic dermatitis occurs on the face, chest, back, scalp and other parts of the body, manifested by erythema, flaking and other symptoms, sometimes accompanied by itching. Heredity, diet, irregular life can cause seborrheic dermatitis. In addition to the above factors, we can not rule out other causes, it is recommended that the patient timely to the hospital, under the guidance of the doctor for standardized treatment.