The cause of this disease is not known. Western medicine believes that the disease is an inflammatory condition based on seborrhea and may be related to increased sebum production or changes in its chemical composition. Recently, many scholars believe that the symbiotic Malassezia furfur may be related to the onset or aggravation of seborrheic dermatitis with the normal population. It is also believed that the overgrowth of Malassezia furfur and its metabolites into the epidermis can lead to an immune response. Individuals with seborrheic dermatitis may be triggered by fatigue, emotional stress, or infection. AIDS patients often present with severe disseminated seborrheic dermatitis, which may be related to the overgrowth of Malassezia furfur due to immune deficiency. In addition, mental factors, spicy and oily food, vitamin B deficiency, and alcohol addiction can aggravate the disease. Studies have found that the risk of the disease is age-related, with infants aged 3 months and younger and adults aged 30 to 60 years at higher risk of developing the disease. Some medications, such as interferon, lithium, and osteopontin, may also predispose people to seborrheic dermatitis. Seborrheic dermatitis is known as leucoderma in Chinese medicine. It is believed that the onset of seborrheic dermatitis is mainly caused by dampness and heat and the sensation of wind. The spleen and stomach are not able to transport and transform properly, which results in dampness and heat. Or the wind-heat evil attacking outside, depleting the yin and blood for a long time, causing yin injury and blood dryness; or the body with dry blood, feeling wind-heat evil again, blood deficiency and wind, wind-heat and dry evil blocking the skin, resulting in skin loss of moistening.