Q. I have a 2-year-old Doberman that lives outside and for the past year has suffered on and off with what the veterinarian calls a "staph bacterial infection." His skin gets a bumpy, moulty appearance and becomes dry and flaky. His hair is falling out, and he bleeds easily around infected areasmostly under his chin and on his hind legs and back. Oral antibiotics and topical solutions clear it up for a while, but the infection returns once the medicine is finished. How can I prevent this condition?

A. Welcome to the frustrating world of recurrent and persistent dog dermatitis.

Skin disease is caused by primary factors and complicated by secondary factors. Primary conditions include hormonal or endocrine imbalances, such as hypothyroidism and Cushing's disease, allergies to food, pollen, dust, molds, human dander, fleas and insects, and external parasites. Genetic diseases such as primary seborrhea, which causes an excessive production and turnover of skin layers, are important in certain breeds. Fungal infections such as ringworm are commonly seen in younger dogs. Many internal diseases can affect the coat health by affecting the dog's overall immunity. Nutritional deficiencies in vitamin A and zinc can contribute to skin disease. Cancers and immune-mediated diseases also commonly affect the skin.

Secondary problemsbacteria and/or yeasts and self-trauma from persistent scratching or gnawingsometimes must be treated before the underlying condition can be identified.

If a skin problem recurs after treatment, seek a specific diagnosis and ask, are we using the correct antibiotic? Have we treated the infection long enough? Are we overlooking underlying conditions?

Talk with your veterinarian and I'm sure you'll come up with some answers.