Pustular acne on the back consider moderate to severe acne, Malassezia folliculitis, etc., which can be treated by general treatment with topical medications, systemic medications, physical therapy and other measures. Moderate to severe acne: Acne is most common in young men and women between the ages of 15 and 30, with lesions occurring on the cheeks and forehead, followed by the chest, back and shoulders, mostly symmetrically distributed, often accompanied by enlarged pores and sebum overflow. In addition to acne and inflammatory papules, there are also a large number of pustules in moderate to severe cases. 1. General treatment: keep the skin clean and hygienic, avoid taking stimulating and spicy food, avoid squeezing and scratching the skin lesions, and eat a light diet, control the intake of sugar and milk, keep the bowel movement smooth, and avoid staying up all night. 2. Topical medication: Commonly used medications include retinoic acid ointment, benzoyl peroxide gel, fusidic acid cream, salicylic acid cream and so on. 3. Systemic medication: doxycycline, minocycline and other antibiotics can be taken, together with isotretinoin. Androgenic can take spironolactone, anti-androgen treatment. 4. Physical therapy: strong pulse dye laser, LED blue light, fractional laser and other physical therapy measures. Malassezia folliculitis: it occurs in the neck, forehead, back of shoulder and other parts of the body, mostly symmetrically. Typical lesions are inflammatory follicular papules, papules or small pustules, hemispherical, 2-4mm in diameter, surrounded by a red halo, and can be extruded with powdery fat-like substances. Treatment should choose good permeability of the topical antifungal drugs (such as ketoconazole cream, etc.), can also be supplemented with 2% ketoconazole lotion or 2.5% selenium disulfide shampoo bath. If the lesions are generalized and the inflammation is severe and the effect of external drug treatment is not good, oral antifungal drugs, such as itraconazole capsules, can be combined. It is recommended to go to the hospital for examination first, to clarify the cause of the disease, and then follow the doctor’s instructions for treatment.