Acne at the junction of the neck and chin may be caused by acne, folliculitis, and contact dermatitis. 1. Acne: The cause of acne is not clear, and it is considered to be related to heredity, dietary habits, emotional fluctuations, endocrine abnormalities and other factors. Patients will have pimples, inflammatory papules, cysts, pustules and other manifestations at the hair follicles. Therefore, patients with acne at the junction of neck and chin will have symptoms of acne. 2. Folliculitis: Folliculitis is caused by Malassezia infection, and the patient’s skin surface will have follicular papules, papules, small pustules, itching, oil overflow and other symptoms. If folliculitis occurs at the junction of the patient’s neck and chin, there will be a manifestation of acne. 3. Contact dermatitis: contact dermatitis is mostly considered to be contact with certain exogenous substances resulting in acute and chronic inflammation of the skin, the patient’s skin will have pimples, papules, blisters and other manifestations. If the patient has contact dermatitis at the junction of the neck and chin, it may manifest as acne. Acne at the junction of the neck and chin may also have other causes (such as boils), it is recommended that the patient consult a doctor in time, the doctor will identify the cause of the disease and choose targeted measures to treat, do not self-medication.