Sebaceous nevus, also known as congenital sebaceous gland abnormality, is a disease formed due to the hyperplasia of sebaceous glands. The exact cause of the disease is not known, and it may be related to a genetic mutation or other factors. Sebaceous nevus is formed due to abnormal development or hyperplasia of sebaceous glands caused by genetic mutation. In childhood, sebaceous glands are often immature and may show incomplete differentiation of the hair follicle structure, and undifferentiated cell cords resembling embryonic hair follicles are common. The lesions often appear as round, ovoid or banded plaques with irregular edges. In adolescence, a large number of mature or nearly mature sebaceous glands may be present, and the lesions are often hypertrophied and nodular. In old age, the rash is hard and warty in texture. If you suffer from nevus of sebaceous glands, it is recommended that you seek medical attention and choose the treatment according to the situation.