Pimples on the face may be caused by acne, but also by contact dermatitis, folliculitis and other diseases that manifest as pimples. 1. Acne: Typical symptoms include pimples, papules and pustules on the skin, which are most common on the face, chest and back, etc. Bacterial infections, increased secretion of sebaceous glands, abnormal keratinization of hair follicle openings, blocked pores, and hormonal disorders may all lead to acne. 2. Contact dermatitis: the cause of the disease is considered to be related to skin contact with exogenous irritating and allergic substances, and the patient will have well defined erythema, papules, itching and other symptoms, or even edema, blisters, etc., which is commonly found in the areas of contact with foreign objects. 3. Folliculitis: pathogen infection, wearing tight clothes and cosmetics and other factors may induce folliculitis, clinical manifestations of red papules, pustules, etc., commonly found on the head and face, chest and back. There are many reasons for acne on the face, and it is recommended that patients seek medical examination to clarify the cause and follow the doctor’s instructions for treatment.