The appearance of red and hard pimples on the chest is considered to be acne, folliculitis, sebaceous cysts or keloids. In the pre-pimple formation period as well as the recovery period of the lesions, the pimples are likely to behave as hard textured red pimples. If acne and folliculitis form pustules, the texture is softer and patients may also experience discomfort such as itching and pain: 1. Acne: The onset of this disease is associated with increased androgen levels, increased sebaceous gland secretion, overproliferation of Acinetobacter propionicus and abnormal sebaceous gland keratinization, which can involve the head, neck and trunk. The lesions may appear as pimples, papules, or pustules. If the lesions are solitary and mild, they can usually fade on their own. In severe cases, a combination of antibiotics is required. If the condition is caused by abnormal androgen levels in women, anti-androgen drugs can be used under medical supervision. In addition, physical therapy can also be taken, such as laser, red and blue light, also have some effect; 2, folliculitis: infectious folliculitis is common, the causative agent is mostly Staphylococcus aureus, the whole body has hair follicles distribution parts may appear folliculitis, often manifested as hair follicle-centered red papules, with pain, itching and other symptoms. The disease can be self-healing, pay attention to local skin cleaning can be, the progression of the disease can involve the deep hair follicle tissue, the development of boils, carbuncles, etc., according to the severity of the disease oral or topical antibiotics and other treatment; 3, sebaceous cysts: caused by sebaceous duct obstruction, cysts hard medium, the patient mostly no obvious symptoms. The treatment is mainly based on surgical excision. 4. Keloid: It can be secondary to skin trauma and is characterized by overgrowth of scar-like connective tissue, which is higher than the skin surface, hard and tough, nodular, striped or lamellar. Treatment is more difficult and can be improved by medication, surgery, freezing, photoelectric therapy and other measures.