1, nipple dysplasia, congenital malformation, concavity and other causes of breast hole occlusion. 2, inflammation: previous inflammation of the breast ducts in the region due to inflammatory hyperplasia resulting in luminal narrowing and occlusion. 3, degenerative changes in the breast: multiple pregnancies lead to degenerative changes in the breast, middle-aged and elderly women due to ovarian decompensation breast ducts are degenerative changes, duct wall relaxation, muscle epithelial cells contraction function is reduced, the accumulation of secretions in the duct. 4, childbirth and breastfeeding: especially with lactation disorders, breastfeeding habits, poor hygiene, all of the above factors can cause breast hole occlusion. 5, bacterial infection: some scholars believe that the disease may be related to bacterial infection, especially anaerobic bacterial infection. 6, breast trauma: trauma leads to damage to the mammary gland structure, causing breast hole occlusion. 7, endocrine disorders: changes in the level of sex hormones in the body caused by various reasons, mainly the elevation of pituitary lactogen causing dilation of the breast ducts, followed by a series of pathological changes. 8.Smoking：Bun-dred
Has reported that smoking is also an important factor, that the accumulation of lipid peroxides, ferritin, niacin and other metabolites in the breast, provoking restricted tissue damage, leading to anaerobic bacteria breeding in the milk ducts and causing the typical manifestation of septicemia.