Acne grading and combination therapy The grading of acne reflects the severity of acne and the nature of the lesions, and the different severity of acne and different types of lesions respond differently to different treatments, so the treatment of acne should be based on the grading of the corresponding therapeutic drugs and means. In addition, the mechanism of action of different drugs often targets different parts of the acne pathogenesis, so the combination of different treatment methods can produce a synergistic effect of treatment, thus increasing the efficacy. Of course, the treatment plan for acne is not set in stone. It should be changed flexibly according to the actual situation of the patient to fully reflect the principle of individualized treatment. Level I treatment: Topical treatment is mainly used. Topical retinoids are preferred. If necessary, benzoyl peroxide or salicylic acid can be added to improve the efficacy. The use of medications that exfoliate, dissolve acne, inhibit sebum secretion and antibacterial effects is complemented by medical skin care products that moisturize, repair and reduce hyperpigmentation, as well as physical therapy such as acne removal, red and blue light and complex color light. Level II treatment: Usually topical treatment with retinoids is combined with benzoyl peroxide or other topical antibacterial medications. In order to avoid local adverse reactions, one drug can be used every other day or both drugs can be used alternately in the morning and evening when retinoic acid is combined with benzoyl peroxide treatment. The use of oral antibiotics may be added if topical treatment is not effective, or physical therapy methods such as blue light irradiation and fruit acid therapy may be added. Level III treatment: These patients are often treated with combination therapy, in which systemic antibiotics are one of the basic treatment methods, ensuring an adequate course of treatment. Oral antibiotics and topical retinoids, benzoyl peroxide or other antibacterial drugs are recommended. For female patients with indications and contraceptive requirements, anti-androgen medication can be chosen. Oral anti-androgen medication combined with antibiotics can be considered for individual female patients. Other treatment methods (such as red and blue light; compound color light and photodynamic therapy, etc.) can also be used in combination. Those with poor results may be treated with oral isotretinoin alone or with concurrent topical benzoyl peroxide. For those who have been systematically applying antibiotics for more than 2 months, the addition of benzoyl peroxide, an antimicrobial agent that does not cause bacterial resistance, is necessary to prevent and reduce the development of drug resistance. Level IV treatment: Oral isotretinoin is the first-line treatment. For those with more inflammatory papules and pustules, a combination of systemic antibiotics and topical benzoyl peroxide may also be used first, and then switched to oral isotretinoin when the inflammation improves. There is no evidence-based medical evidence to support oral isotretinoin in combination with antibiotic therapy. There is no evidence to support the use of oral isotretinoin in combination with antibiotics.