Primary seborrhea is an inherited disorder of the skin in which the outer layer of the skin (the epidermis), the sebaceous glands, and part of the hair follicles are hyperproductive. The rate of cell turnover in these tissues is significantly increased, causing excessive production of scale (dry flakes of skin) and sebum (fatty lubricating substance). Seborrhea oleosa is the more greasy form while seborrhea sicca is a dryer form. Many dogs have a combination of both types. Chronic waxy ear infections (otitis externa) also occur commonly as part of this disorder.
...Primary seborrhea is most commonly seen in the American cocker spaniel, West Highland white terrier, English springer spaniel, and Basset hound.
...Early evidence of the disorder such as mild flaking and dullness of the coat may appear as young as 10 weeks of age. Because these signs are subtle, they often go unnoticed. However, usually by a year to 18 months, the signs have become pronounced. Affected dogs commonly have a dull coat with excessive scaling, a greasy feel and smell to the skin (especially in areas of body folds), smelly waxy ears which may be infected, thickening of the foot pads, and dry brittle claws. Some breeds (West Highland white terrier, cocker spaniel, springer spaniel, Basset hound, Shar-pei) are more prone to the greasy form of seborrhea (seborrhea oleosa) with chronic ear infections and greasy skin, while others (Doberman pinscher, Irish setter) are more likely to develop the dryer form (seborrhea sicca)
Dogs with seborrhea are prone to secondary infections, either bacterial or yeast, and frequently develop skin lesions and associated itching. This condition is called seborrheic dermatitis. Scratching leads to worsening of the lesions and spread of the infection.[/b]
