Derm's dirty Dozen, The top chronic, recurrent cases destined to cause frustration

Derm's dirty Dozen, The top chronic, recurrent cases destined to cause frustration

Oct 01, 2004

Carlo Vitale, DVM, ACVD.
I have noticed that as the years go by, I have begun to feel more and more frustrated with certain skin cases (cats included) that are referred to me in my practice in San Francisco and the surrounding Bay Area.

I don't see any differences geographically with the types of cases in my three practices in San Francisco, San Leandro or Walnut Creek. These cases follow me everywhere.

I have been in private practice for seven years and sense a growing number of cases (or is it just cumulative?) that are on my dirty dozen list.

During recent years, there has been an explosion in the numbers of cases seen daily with very concerned and frustrated owners with pets plagued with very unusual and/or recurrent diseases to treat and manage. I don't recall the existence of these cases as a dermatology resident at the University of California-Davis Veterinary Teaching Hospital (UC-Davis) under the legendary Dr. Peter Irhke. Maybe I was just too naive and actually thought I could cure all.

This month, we will look a little closer at the top dermatological problems that plague your patients.

  • Disease 1:

Canine recurrent superficial pyoderma I wrote an article recently in DVM Newsmagazine concerning this very same topic, so I won't go into too much detail. But this disease is so frustrating that it deserves repeating! I would have to say it also is the most-common case that is referred to me.

First of all, this disease is essentially, an immunologic dysfunction. Staphylococcus intermedius is a resident inhabitant of the normal skin, ear canal, anal sac and dog hairs. They actually live on the skin and hair in normal, healthy dogs. The problem is that some dogs are not normal, they develop pyoderma. Superficial pyoderma manifest usually in the glabrous skin (axillae and groin) or trunk. It spares the face and limbs for the most part. We all know what it can look like: papules that evolve into pustules, epidermal collarettes, or simply redness and alopecia (surface pyoderma). It tends to start early in age (first few years of life), occur in Retrievers, many small breeds such as Terriers (except Border Terriers) and Pit Bulls. Pruritus may be severe or absent. Often an odor accompanies the pyoderma.

Treatment includes anti-staphylococcal antibiotics for at least 21 days such as potentiated sulfa-type antibiotics, cephalexin or fluoroquinolones. I often recommend twice-weekly shampoo therapy with benzoyl peroxide-containing shampoos, chlorhexidine-based or ethyl lactate-based shampoos. We know now that certain dogs with recurrent pyoderma have a higher carriage of cocci on the skin even when the dog appears clinically normal, and these cocci tend to adhere more strongly to corneocytes. So, it makes sense to bathe frequently even when the patient appears normal.

Here is the difficult part: The pyoderma returns after treatment. I believe that the most common reason is still due to flea allergy. A very close second is atopic dermatitis (which is next on the list). Food allergy, primary seborrhea (as described in the Cocker Spaniel) and demodex are distant thirds. A complete work-up also may include thyroid function measurement or an ACTH stimulation test to search for endocrinopathies that are also incriminated in recurrent pyoderma in the dog.

Dogs presented with superficial pyoderma primarily have lesions confined to the trunk. The most common lesions identified included papules and pustules.
After the treatment and diagnostic plan addressing these possible underlying causes reveals normal findings, you will be left with primary or idiopathic pyoderma.