At present, the cause of this chronic external nasal skin injury is not very clear. It is generally believed to be related to a kind of hair follicle keratosis parasitic in sebaceous glands of hair follicles. In addition, gastrointestinal dysfunction, endocrine disorders (such as irregular menstruation, menopause, emotional instability, etc. ) and chronic infection in the body may be the pathogenic factors of rosacea People who often drink, smoke and love spicy food have a higher prevalence rate. The root cause of rosacea's redness on the face and nose is the long-term expansion of local capillaries, which leads to skin congestion. Erythema of rosacea is often located at the tip of nose, chin and brow, and the boundary between erythema and surrounding skin is unclear. With the development of the disease, the nose is red and swollen for a long time, the capillaries are dilated, and there may be small papules and small pus scars on the tip of the nose; In severe cases, small nodular protrusions of different sizes can be seen on the tip of the nose, which looks like vegetation, so it is also called "nasal wart". Rosacea has little effect on general health except beauty. It's just that the nose often feels local fever. If complicated with infection, it may be accompanied by pain, and other symptoms are not obvious.