There are several reasons why acne occurs on both sides of the nose: first, genetic factors: some patients have a family history; second, endocrine factors: androgen secretion is more vigorous during adolescence, resulting in increased sebaceous gland function activity, large amounts of oil secretion, keratinization of hair follicle sebaceous gland ducts, and the formation of acne on the skin surface; third, infection factors: too much oil on the skin surface, resulting in the proliferation of Propionibacterium acnes, causing inflammatory papules locally; fourth, drug factors: such as oral iodide, hormones, etc.; fifth, other factors: such as cosmetics, frequent late nights, eating sweets, chili peppers, etc.