Rosacea, also known as acne rosacea, is a chronic inflammatory skin disease that occurs in the nose and perinasal area, mostly in middle-aged adults between 30 and 50 years of age, with more women than men, but severe cases are often seen in men. Its etiology and pathogenesis are not fully understood, and hypotheses have previously been proposed around photodamage, vascular alterations and microbial infections, suggesting that chronic UV radiation can disrupt the epidermal barrier as well as the perivascular connective tissue, leading to abnormalities in the homeostasis of the cutaneous vascular system. Follicular worms and recurrent local infections are among the important factors in the pathogenesis. Consumption of spicy food, alcohol consumption, high temperature and cold stimulation, mental stress and emotional agitation, and endocrine disorders can act as triggering and aggravating factors for this disease. Recent studies suggest that the intrinsic immune system is also involved, and elevated serine protease activity and abnormal expression of antimicrobial peptides in the lesions are also associated with it. Clinical features The typical clinical manifestations are transient and persistent erythema, capillary dilatation, papules, pustules, and in some cases, nasal redundancy due to hyperplasia of the sebaceous glands, mainly in the midface. According to its clinical characteristics, it is divided into 3 stages. 1. Erythema phase: It mainly manifests as erythema that lasts for a few hours to a few days, which can eventually develop into capillary dilation. 2.Pimple and pustule stage: it shows persistent erythema, a large number of capillary dilatation and inflammatory papules and pustules. 3.Nasal flaccid stage: It occurs only in a small number of patients and manifests as larger inflammatory nodules, boil-like infiltration and tissue hyperplasia. The primary features of rosacea, including facial erythema (temporary erythema), persistent erythema, papules, pustules, and capillary dilation. persistent erythema lasting for more than 3 months in the central region of the face is the most important clinical feature of rosacea, according to Crawford et al. Dilated capillaries are a common clinical feature of rosacea, but are not necessary for the diagnosis of rosacea. The presence of one or more of these clinical features in the central region of the face supports the diagnosis of rosacea. Secondary features include a burning sensation on the face, dry skin, edema, ocular involvement, peripheral area involvement, and hyperplastic nasal flap-like lesions. Secondary features may coexist with one or more primary features, although some patients may present with only secondary features. In 2005, the National Commission of Experts on Rosacea published a rosacea classification guideline, which divides rosacea into 4 subtypes Erythema capillarum: Patients have a history of facial erythema, which presents as a persistent erythema in the center of the face. The erythema usually exceeds 10 minutes and capillary dilation is more common. Papulopustular type: The patient presents with persistent erythema in the central part of the face accompanied by papules or pustules. Superfluous type: often secondary to, or concurrent with, erythema capillarum and papulopustular type. Ocular type: Clinical manifestations include blepharitis, conjunctivitis, abnormal tear production in 40% of patients, dry eyes, foreign body sensation, tearing, photophobia, blurred vision, etc. Ocular symptoms may precede skin manifestations in more than 20% of patients.