Acne vulgaris, commonly known as pimples, is a chronic inflammatory skin disease of the sebaceous glands of hair follicles that occurs in adolescence. It has a prevalence of 86-90% and has a significant psychological and social impact on adolescents. Early treatment of this disease is important. Timely and standardized diagnosis and treatment can shorten the course of the disease and avoid or reduce the occurrence of various complications. Acne is mainly associated with excessive sebum secretion, blockage of hair follicle sebaceous gland ducts, bacterial infection and inflammatory response, as well as diet, emotions, medications and many other factors. Clinical manifestations of acne] Acne can manifest as blackheads, whiteheads, inflammatory papules, pustules, nodules, cysts, and so on. After acne heals, it is easy to form hyperpigmentation, i.e., acne marks, enlarged pores, or even scar-like damage, which can affect beauty or even disfigure the face. The grading of acne can help in the evaluation of acne treatment and efficacy. According to the nature and severity of lesions, acne can be classified into 3 degrees and 4 grades: Grade 1 (mild): acne only Grade 2 (moderate): acne + inflammatory papules Grade 3 (moderate): acne + inflammatory papules + pustules Grade 4 (severe): acne + inflammatory papules + pustules + nodules, cysts or scars [Principles of acne treatment] The principles of acne treatment are exfoliation, dissolution of keratin, sterilization and anti-inflammation, as well as individualization of treatment. 1. Treatment of mild acne Mild acne refers to acne, whiteheads or blackheads only, and does not require systematic drug treatment. Topical retinoid preparations can be used, and attention should be paid to eating less spicy and irritating food, removing oil and dirt from the skin surface on the face, and keeping the bowels open to various triggering factors. However, do not often squeeze acne to avoid infection and aggravate the lesions. 2. Treatment of moderate and severe acne Moderate to severe acne should be treated actively to avoid leaving pimple marks or scars. grade 2 acne can be treated with topical agents such as retinoic acid and other drugs that regulate normal cellular keratinization, topical antibiotics such as benzoyl peroxide, etc. grade 3 acne requires systemic application of antibiotics in addition to topical drugs. grade 4 acne requires systemic application of antibiotics in order not to leave complications such as a large number of pimple marks and scarring. For grade 4 acne, it is best to combine physical therapy, such as red and blue light and photodynamic therapy, with drug therapy (antibiotics, isotretinoin, etc.). If necessary, short-term application of glucocorticoids is also required. 3.Physical therapy for acne For patients who cannot tolerate medication or do not receive medication, and for patients with grade 4 acne, physical therapy or combined physical therapy is a good choice. The physical treatments carried out in our department include: photodynamic therapy, red and blue light, fractional laser, and pressed beans combined with blood cupping. Red and blue light treatment for acne is based on the characteristics of the light action of Propionibacterium acnes, that is, Propionibacterium acnes can produce endogenous fecal bacillus and can absorb proto-bacillus through its cell wall receptors. These two types of bacillus are important substances for Propionibacterium acnes to maintain normal metabolism and keep its form and function, while bacillus is a photosensitive substance that can be activated after absorbing specific wavelengths of light, producing monomorphic itch and free radicals, which are Propionibacterium inactivates and plays a role in the treatment of acne. Photodynamic therapy is an exogenous photosensitizer, such as ALA, applied topically to the lesion, which is absorbed through the follicular sebaceous gland unit and participates in the hemoglobin synthesis pathway to produce protoporphyrin, which is excited by specific wavelengths of light to produce monomorphic oxygen and free radicals, thus selectively acting on the follicular sebaceous gland unit and Propionibacterium acnes with minimal damage to surrounding tissues. Advantages of acne phototherapy (1) Reduction of the systematic application of drugs and avoidance of adverse reactions caused by drugs. (2) Effective options for special populations, such as pregnant women (except photodynamic) and others who cannot tolerate drug treatment. (3) No pain or other suffering. (4) While treating acne, it can smooth out fine skin lines, brighten skin tone, and make the skin smoother and softer. 4. Treatment of post-acne scarring Severe and persistent acne is very likely to leave behind acne marks and even scarring such as pits of varying sizes, causing great psychological and social obstacles to patients. In the past, post-acne scarring was generally treated by grinding, but the treatment was not ideal because of the large trauma and the number of treatments. The introduction of fractional laser in our department can improve the depressed scars left after various diseases. 5, acne patients daily life precautions (1) avoid emotional tension, keep a happy mood. Ensure sufficient sleep. (2) Minimize the consumption of greasy, fried foods, sugar, chocolate and spicy, stimulating foods. Eat more vegetables and fruits rich in vitamin C and foods rich in calcium. (3) Pay attention to personal hygiene, avoid scratching and squeezing, and wash your face with warm water, but frequent washing will aggravate acne. (4) Avoid taking medications that may cause or aggravate acne. (5) Avoid using thick cosmetics and excessive makeup.