Many people have a lot of pimples on their chest and back, some say it is mites, commonly used to remove mites shower gel or soap bath; some say it is dampness and heat in the body, to get rid of dampness; others say it is a manifestation of toxins in the body. The “pimples” on the chest and back in the end is what? Acne on the chest and back is usually seen in acne, Malassezia folliculitis, bacterial folliculitis, etc. Generally acne onset in adolescence, common sites for the face, neck, chest and back, mostly greasy skin, rash type variety, can be seen at the same time pustules, acne (whiteheads, blackheads), nodules, cysts, scarring, etc.. The causes of acne are complex and there are many reasons for recurrence, such as fatigue and stress, poor sleep, spicy food, food intolerance, family history, low resistance, repeated bacterial (mainly Propionibacterium acnes) infections, high oil secretion, and poor cosmetic application. How to use medication requires symptomatic treatment according to the patient’s different etiology. Meanwhile, modern laser technology and cosmetic methods have played many irreplaceable roles in helping to treat different side effects in various stages of acne: for example, red acne scars can be treated with laser, intense light, and red light; photodynamic therapy for moderate and severe infected acne is very effective; fractional laser, gold microneedle, and plasma laser for worm-like depressed scarring are very effective; black Acne head can be treated with acne needle + red and blue light; rough pores and dull skin tone can also be treated with fruit acids. Malassezia folliculitis is related to Malassezia infection, Malassezia is a fungus that exists on the surface of normal human skin, after the decline of human immune function or long-term use of hormones (internal or external), Malassezia spore phase into mycelium phase (mycelium has the role of skin invasion) and the onset of the disease, can be manifested as pustular red papules, rash is more uniform and consistent, accompanied by itching discomfort, need antifungal treatment. Bacterial folliculitis is mainly caused by Streptococcus or Staphylococcus aureus infection, centered on the hair follicle and manifested as redness, swelling, heat and pain, mostly acute onset, can be cured in about 1-2 weeks; however, some people are recurrent, the disease is prolonged, the cause needs to be identified, such as immune deficiency, wasting disease, etc.. Treatment requires antibiotics, mainly topical drugs in the early stage, and oral medication in severe cases. Local phototherapy is more effective in relieving inflammation and pain, and surgical incision and drainage of pus is required if necessary.