A disease of the sebaceous glands: Seborrhea is characterized by excessive secretion of sebum or an alteration in its quality, resulting in an oily coating, crusts, or scales on the skin.

A functional illness of the sebaceous glands is marked by a morbidly increased discharge in the amount of the sebaceous matter, usually resulting in an excessive amount of sebum.

A redness and scaling in the nasolabial creases: Because Agatha had an itchy nose which was becoming red and scaly, she went to her doctor who informed her that it was a case of nasolabial seborrhea and was typical of a deficiency of vitamin B.