Seborrheic dermatitis, also known as seborrheic eczema, is a chronic papular, scaly, superficial inflammatory skin disease that occurs at the location of seborrhea. It tends to occur in areas with abundant sebaceous glands, such as the head and trunk. It is more common in adults and newborns, and can be accompanied by itching to varying degrees. The cause of the disease is not completely clear. It is generally believed that it may be related to the increase of sebum secretion or the change of its chemical composition. In addition, it may be related to the colonization and infection of Malassezia. Of course, factors such as spirit, diet, lack of vitamin B family, and alcoholism also affect the occurrence and development of the disease to varying degrees.