Seborrheic dermatitis, also known as seborrheic eczema, is a chronic papular squamous superficial inflammatory skin disease that occurs in areas of sebum secretion. It is more commonly found in adults and newborns and can be accompanied by varying degrees of itching. In infants, seborrheic dermatitis generally occurs from the 2nd to the 10th week after birth, with common sites being the scalp, face, nasolabial folds, nasal hair area, around the ears, and in skin folds. The rash typically appears as greasy red patches, or may be covered with greasy gray-yellow or brown-yellow thick crusts. In severe cases, there might be erosion and exudation. The condition generally diminishes or even heals within two months, though in very rare cases, the rash may suddenly spread throughout the body, causing diffuse erythema and significant desquamation. This is known as seborrheic erythroderma, which represents a severe stage of the disease. Treatment mainly involves the use of topical medications, focusing on mild, safe, and low-irritant drugs for application. Commonly used medications include zinc oxide oil, antibiotic ointments, traditional Chinese medicine ointments, tacrolimus ointment, and pimecrolimus cream. Additionally, it is important to advise the parents to ensure the baby has a regular lifestyle with sufficient sleep and to avoid various mechanical irritations. It is also recommended to use less hot water and harsh alkaline soaps for bathing.