Seborrheic dermatitis, also known as seborrheic eczema, is a chronic inflammatory skin disease that occurs on the head, face, chest, back and other areas with high seborrhea. The cause of the disease has not yet been completely cleared. It is generally believed that infection by pathogenic organisms such as Malassezia ovalis and Acinetobacter can cause changes in sebum composition (mainly increase in free fatty acids) and infectious metaplasia, resulting in inflammatory reactions in the skin. Spirituality, diet, B vitamin deficiency, and alcoholism can all affect the occurrence and development of the disease to varying degrees. You should maintain a regular life and get enough sleep; limit fatty and sugary diet, avoid alcohol and spicy stimulating food, eat more fruits and vegetables; avoid all kinds of mechanical stimulation and use less alkaline soap. Treatment should also be analyzed according to the performance of the skin lesions. For heavier patients, blue light treatment and phototherapy can be taken. It can improve the inflammatory skin quality, and part of it can achieve the purpose of radical treatment.