1.what is acne
Acne is a chronic inflammatory skin disease of the pilosebaceous unit, which mainly occurs in adolescents, and has a great psychological and social impact on adolescents. The clinical manifestations are characterized by pleomorphic skin lesions such as acne, papules, pustules, and nodules that occur on the face.
2.cause of disease
The occurrence of acne is mainly related to factors such as excessive sebum secretion, blockage of the pilosebaceous duct, bacterial infection and inflammatory response. After entering puberty, the level of androgens, especially testosterone, in the human body increases rapidly, which promotes the development of sebaceous glands and produces a large amount of sebum. At the same time, the abnormal keratinization of the ducts of the pilosebaceous glands causes blockage of the ducts, obstruction of sebum discharge, and the formation of keratin plugs, that is, micro-comedones. A variety of microorganisms, especially P. acnes, proliferate in the hair follicle. The lipase produced by P. acnes decomposes sebum to generate free fatty acids, and at the same time chemotactic inflammatory cells and mediators, eventually inducing and aggravating the inflammatory response.
The skin lesions tend to occur on the face and upper chest and back. The non-inflammatory skin lesions of acne appear as open and closed comedones. The typical skin lesions of closed comedones (also known as whiteheads) are skin-colored papules about 1 mm in size without obvious follicular openings. Open comedones (also known as blackheads) appear as dome-shaped papules with markedly dilated hair follicle openings. Further development of comedones can evolve into various inflammatory skin lesions, which manifest as inflammatory papules, pustules, nodules, and cysts. Inflammatory papules are red and vary from 1 to 5 mm in diameter; pustules are uniform in size and filled with white pus; nodules larger than 5 mm in diameter are induration and painful to the touch; cysts are deeper and filled with pus and blood mixture.
These lesions can also coalesce to form large inflammatory plaques and sinus tracts. Hyperpigmentation, persistent erythema, and pitting or hypertrophic scarring often remain after resolution of inflammatory skin lesions. Clinically, according to the nature and severity of acne lesions, acne is divided into grades 3 and 4: grade 1 (mild): only acne; grade 2 (moderate): in addition to acne, there are some inflammatory papules; 3 Grade (moderate): In addition to acne, there are more inflammatory papules or pustules; Grade 4 (severe): In addition to acne, inflammatory papules and pustules, there are nodules, cysts or scars.