Seborrheic dermatitis, also known as seborrheic eczema, is not actually eczema. It is a chronic, papular, scaly superficial inflammatory skin disease that commonly occurs in areas rich in sebaceous glands, such as the head, face, and trunk, and can be accompanied by varying degrees of itching. The causes of this condition are primarily believed to be associated with increased sebum secretion or changes in the chemical composition of the cortex. It is also related to the colonization and infection of Malassezia, stress, diet, deficiency of B vitamins, alcohol consumption, and other factors. The characteristic rash consists of follicular papules that expand and merge into dark red or yellow-red patches, covered with oily scales or crusts. Exudation, crusting, and erosion can occur, resulting in eczema-like changes.