From time to time, I encounter patients with rosacea in outpatient clinics. Although not as numerous as acne patients, epidemiological data indicates that about 4% of the population in China develops it. As mentioned in previous articles, acne and rosacea are two completely different diseases with different causes. We have updated our knowledge about acne quite a bit and will continue to do so in the future. As previously mentioned in the article on facial flushing, let’s now take a closer look at the disease rosacea. What is rosacea? Rosacea, is a chronic inflammatory skin disease with erythema and dilated capillaries that occurs mainly in the center of the face. It is characterized by facial flushing, erythema, capillary dilation, papular pustules, and hyperplasia of the nose. It is most common in middle-aged people between 30 and 50 years old, and is more common in women. What are the causes of rosacea? The pathogenesis of rosacea has not yet been fully studied. However, in addition to genetic susceptibility, possible pathogenesis includes neurovascular disorders, disruption of skin barrier function, and inflammatory response. Abnormal neurovascular function may lead to abnormal regulation of neurovascular function, increased blood flow in the skin, and vasodilation; destruction of the skin barrier leads to greater sensitivity of the skin to external environmental stimuli, causing a series of neuroinflammatory reactions; and inflammatory reactions caused by various external stimuli, neuroinflammatory mediators or crepitant mites lead to further aggravation of symptoms. The three interact with each other and eventually lead to burning, dryness, redness, stinging, itching, papules, and swelling of the patient’s skin. What are the clinical manifestations of rosacea? Clinically, rosacea is divided into 4 subtypes. 1. Erythematous capillary dilatation type Erythematous spots appear in the middle of the face, especially on the nose, cheeks, between the eyebrows and chin, and are symmetrically distributed. Erythematous spots are initially temporary, and when eating spicy food or hot drinks, when the ambient temperature rises, or when emotionally impulsive, the face is flushed and congested, and the face feels burning. After repeated attacks, superficial dendritic capillary dilation appears on the nose, nasal tip and cheeks, with local persistent redness, often accompanied by enlarged nasal follicular pores and seborrhea. 2.Pimple-pustular type can appear on the basis of erythema and capillary dilation, or acne-like follicle-like papules and pustules can appear repeatedly at the onset. When the damage is deeper and larger, boils, cysts, and deep inflammatory nodules are formed. The follicular openings on the nose and cheeks are enlarged, and may appear over a period of several years, sometimes lightly and sometimes heavily. In middle-aged female patients, the rash often worsens before menstruation. 3, hyperplastic hypertrophy type also known as rosacea. Only in a few patients, mostly in men over 40 years old due to long-term congestion, repeated infections, hyperplasia of connective tissue in the nose, abnormal enlargement of sebaceous glands, hypertrophy of the nasal end, dark red or purplish red. There are enlarged nodules on the nose, and the table is uneven, forming a superfluous tumor-like called nasal superfluous. 4, eye type In addition to skin performance, the eyes are often involved. Clinical manifestations are blepharitis, conjunctivitis, occasionally can cause keratitis and sclerenitis, patients can appear dry eyes, foreign body sensation, tearing, photophobia, blurred vision, etc., eye involvement symptoms and rosacea symptoms are not parallel to the severity of the relationship.