Seborrheic dermatitis, also known as seborrheic eczema, is a chronic inflammatory skin disease that occurs in areas with high sebum production, such as the head, face and chest and back. The symptoms of seborrheic dermatitis gradually appear to change, usually with the first signs being flaky skin and scalp. Symptoms most often occur on the skin of the scalp, behind the ears, on the face and in areas of skin folds. The skin surface may be yellow, white or light gray in appearance. Redness and peeling may also occur near the eyelashes, on the forehead, around the nose, on the chest and on the skin of the upper back. In more severe cases, yellow to slightly red scaly papules appear along the hairline, behind the ears, ear canals, eyebrows, bridge of the nose, around the nose, chest, and upper back. Often, patients will experience mild redness, scaly skin lesions, and in some cases, hair loss. Other symptoms include patches of scaly or thick skin on the scalp, red, oily skin covered with scaly white or yellow scales, and yellow or white scales that may be attached to the hair shaft. Seborrheic dermatitis is classified into two types of Chinese medical evidence: wind-heat and blood-dry evidence and gastrointestinal damp-heat evidence. The symptoms are also different. Seborrheic dermatitis may occur in people of any age, and its manifestation is mainly itching discomfort, sometimes due to excessive scratching can occur skin infection, resulting in less obvious symptoms of flaking, but mainly redness, pain, and running water. It requires prompt treatment.