Acne vulgaris is a chronic inflammatory and disfiguring disease of the sebaceous glands of the hair follicles. Acne vulgaris is a chronic inflammatory disease of the sebaceous glands of the hair follicles. According to foreign scholars, up to 80% of adolescents have acne, compared to 5% of adults. Classification of Acne Acne manifests itself in different ways, ranging from physiologic pimples to inflammatory papules, pustules, nodules and cysts, and in severe cases, it is also prone to scarring and facial melanin deposition. Acne not only affects a person’s aesthetic appearance, but also has a certain impact on a person’s emotional and mental health and even behavior, it has become a psychosomatic disease that cannot be ignored. Endocrine factors Modern research has shown that endocrine factors, especially the metabolic level of androgens, are important factors in the development of acne. Androgens are mainly responsible for increasing the activity of sebaceous glands in the pathogenesis of acne. High secretion of androgens stimulates the proliferation and secretion of sebaceous gland cells. Testosterone in androgens binds to the corresponding receptors under the action of enzymes and regulates the activity of follicular sebaceous glands, resulting in abnormal keratinization of follicular sebaceous glands. The keratinized cells adhere to each other and block the follicular ducts, thus leading to the development of acne. Pre-pubertal and adolescent female acne sufferers have low levels of estradiol and relatively high levels of testosterone during the premenstrual period, which can lead to the development or exacerbation of acne. Most of the post-pubertal young people are facing great social, family and economic pressures, and their moods fluctuate greatly, making them prone to anxiety, irritability, nervousness and depression. These undesirable emotions that cannot be vented for a long period of time will stimulate the emotional loop of the cerebral cortex and the limbic system, which will lead to an increase in androgens, and finally the formation of post-pubertal acne, which is also known as delayed-onset acne. Exhaustion and frequent late nights will also cause endocrine disruption, thus aggravating the condition. Abnormal keratinization of sebaceous gland ducts Lipids include free fatty acids, linoleic acid, and shark diluted acid. Excessive sebum overflow leads to abnormal functioning of the sebaceous glands and formation of excessive flaking, which leads to bacterial retention and multiplication, which in turn produces localized inflammation. Akamatsu et al. found that the level of linoleic acid in acne patients’ pimples was significantly lower than that of normal people, while the level of palmitic triglyceride was significantly higher. Linoleic acid has a role in maintaining the epidermal barrier function, and also inhibits the production and phagocytosis of reactive oxygen clusters by neutrophils. When too low a concentration of linoleic acid passes through the sebaceous gland ducts, it stimulates epithelial keratinization and the formation of acne. In contrast, glyceryl palmitate reduces the production of hydrogen peroxide by neutrophils and decreases epidermal barrier function through oxidative stress, making it easier for inflammatory transmitters to enter the dermis through the hair follicle and exacerbating the inflammatory response. Microbial infections A physiologic, dynamic balance should be maintained between the skin microbiota and the host and environment. Once this microecological balance is broken, the patient’s facial flora becomes abnormal, which can easily lead to disease. Under pathological conditions, bacteria, especially Propionibacterium (which is also involved in a number of treatments below), can hydrolyze triglycerides in sebum, producing free fatty acids that can stimulate epithelial hyperplasia and hyperkeratosis at the openings of sebaceous glands of hair follicles, the latter of which (hyperkeratosis) causes sebum secretion channels to be blocked and poorly discharged. When sebum, keratin clumps, etc. in the follicle mouth that is the formation of acne, rich in irritating free fatty acids to stimulate the hair follicle caused by inflammatory lesions. In addition, some low molecular peptides produced by bacteria can chemotaxis neutrophils, and the hydrolytic enzymes produced by neutrophils can make the hair follicle wall damaged and ruptured, and all kinds of hair follicle contents spill out of the dermis to cause a varying degree of deep inflammation around the hair follicle. Psychological factors The acne formed pimples, pustules, nodules, cysts, scarring, etc. make people’s beauty impaired, even to the extent of disfigurement, resulting in adolescents suffering from great psychological distress, and some of them will continue to have acne into adulthood. Compared to those without acne, people with acne are more likely to experience depression and anxiety, and their self-esteem and self-satisfaction are lower. This is more pronounced in women than in men, and the longer the condition lasts, the more severe the psychological disorders. Timely and appropriate treatment can significantly improve the appearance of the patient, increase self-esteem and improve quality of life.