Sebaceous cysts are retention cysts caused by the collection of sebum due to blockage of the ducts of the sebaceous glands in the hair follicles. Sebaceous glands are found in the body’s hair follicles and sebaceous glands secrete oil to moisturize the skin. When sweat glands and hair follicles are clogged with dirt or damaged, it can cause narrowing of the sebaceous gland’s drainage ducts. When the sebaceous glands continue to secrete, the secretion accumulates and a cyst is formed. Common causes of sebaceous cysts include clogging of the sebaceous ducts with a large amount of dust in the environment, or bacterial infection, or sebaceous gland lesions that result in an overproduction of sebum or a buildup of metabolites. In addition, sebaceous cysts can also be triggered by poor lifestyle and dietary habits such as staying up late at night, excessive consumption of oily and spicy foods, and not paying attention to skin hygiene. Patients with sebaceous cysts should seek timely medical treatment and standardize the diagnosis and treatment under the guidance of doctors.