Close-up view of the human scalp in a case of severe dandruff accompanied by inflammation of the scalp. The example is probably better described as a type of seborrhoeic dermatitis rather than ordinary dandruff. The oily appearance of the hair and yellow, moist dead skin scales results from the overproduction of sebum, the secretion of the sebaceous glands that reaches the skin surface through small ducts that lead into the hair follicles.