Ask the Vet

Treating Skin Problems

by Dr. Cheryl Burke

Ask the VetDear Doctor,
My 3 year old Pit bull rescue has been itchy, miserable and stinky for at least 6 months. I have bathed him with special shampoos, given him medications and stopped all people food. Nothing is working! What can I do?
Frustrated in Federal Hill

Dear Frustrated,
The treatment of skin problems in veterinary medicine can be an arduous and sometimes expensive task. Without knowing the specifics of your dog’s case, I would like to respond in general terms with how I approach a persistent skin problem.

Home and Medical History:
A thorough history that includes the previous and current details of diet, medications and treatments, including flea and tick medications, heartworm preventative, and supplements. We will ask about any seasonal patterns, household changes,  an owner’s smoking habits and whether any humans in the house have lesions. The outdoor environment that a dog exercises in, any recent travel, the established presence of foxes or coyote in the neighborhood and whether other pets are similarly affected all has relevance in solving the riddle.

Examination:
We will perform a head to toe examination of your dog, noting evidence of flea infestation, areas of irritation or pruritus (itchiness) and specifically any areas that appear to be infected. We may sketch areas on the chart or photograph specific areas that we want to focus on.

Diagnostic Tests:
The following are commonly used tests that veterinarians will perform in the office that can provide valuable information, allowing us to treat specifically or at least logically.

Skin Scraping: We will scrape several areas of skin and put the scrapings on a microscope slide in oil. This allows us to look for the 2 most common forms of skin mites, demodex and sarcoptes.

Skin cytology: After we scrape the skin we will press a clean slide against the skin to obtain a sample of organisms on the surface of the skin or in the lesion. We will stain this slide and can look for the presence of bacterial, fugu or yeast.

Black light: We will often turn out the overhead lights and look at the skin with a black (fluorescent) light. This is a screening test for ringworm that is looking for green hair shafts indicating infection with Microsporum Canis. Not all ringworm infections will fluoresce but if it does, it is virtually diagnostic and therefore specifically treated. Ringworm is a fungal infection of the skin and the 3 common species that infect dogs (and cats) can all infect the skin and hair of humans. It is a zoonotic infection.

Fungal Culture: In our office, we use  a sealed, new toothbrush and comb through the dog’s coat and through the lesions. This toothbrush is pressed into a special culture media that can support fungal growth and will change to a specific color if the organism is in fact ringworm.  A fungal culture takes 10 days or more to grow, but allows us to speciate the fungus, thus better helping us to plan appropriate treatment.

Bacterial Culture and Sensitivity:  Some bacterial infections have been treated with several different antibiotics without success making it possible that the bacteria are resistant to the common antibiotics available. If we suspect this we will obtain a sample of material from a lesion or pustule and submit it to a reference lab for identification and most importantly for a list of antibiotics that are effective against that bacteria. Dogs that live with human medical personnel have an increased risk of being infected or colonized with MRSA (methicillin resistant Staphylococcus aureus.)

Skin Biopsy: Depending on the pattern and severity of the skin changes as well as what treatments have failed, we may suggest that we perform a punch biopsy of  the skin lesions to identify the problem. Certain immune diseases or unusual infections are identified this way. We can often do this with a local anesthetic, but some areas will require a sedative for your dog’s comfort. The samples would be put into formalin and read by a pathologist who looks at the layers of cells and the tissue characteristics to diagnosis the problem.

Blood Tests:  Occasionally a medical or hormonal problem will have dermatologic symptoms. If we suspect a medical problem, we will generally screen a dog for thyroid and other metabolic problems.

Now what??
If parasites have been ruled out by the available in office tests, I often start treatment with antihistamines for allergy control, medications for secondary infections and a plan to begin an elimination diet. This diet would generally be food and protein source that the dog has not had before. Currently I consider fish, venison, and kangaroo to be my preferred elimination protein sources. This doesn’t mean that these proteins are superior in any way ..just different. The most common food allergy in dogs is beef;  organic, grass fed, or raw.. it does not matter. Mixing beef in with venison for example, is not an appropriate elimination diet. Food trials take 8-12 weeks to complete so I generally start this at the beginning of the treatment plan and after the transition is complete, require total loyalty to the regiment.

One of the premises of treatment is to resolve the most severe symptoms and provide relief if we can, even as we work to get to the bottom of the problem.  A second premise is to use less expensive tests, treatments and medications first whenever possible. We strive to use medications with few side effects  and to inform the owner what to expect and what to look for in the event of a drug reaction.  It is important to complete a treatment in order to judge its effectiveness so sometimes patience is needed to complete the course.  Recently we have had clients sharing images electronically to allow us to observe the skin without having to bring the dog in every two weeks.

Of all of the problems your dog might have, skin disease is one that you and your vet will need to be partners in diagnosing and treating.  Good communication of expectations and plan will go a long way to success. By working together logically and carefully, most common problems can be successfully treated in a general practitioner’s office. At any time, or after the routine in office work has been completed, a patient may be referred to a veterinary dermatologist who specializes in the diagnosis and treatment of skin disease in animals.  They have years of additional training that make them experts with challenging problems. Good luck with your little one!

Dr. Cheryl BurkeDr. Cheryl Burke, DVM, CCRP is the proud owner of Paradise Animal Hospital for the past 22 years, practicing companion animal medicine and canine rehabilitation in her hometown community. To reach Dr. Burke or Paradise Animal Hospital call 410-744-4224, or visit www.paradiseanimalhospital.com.

– See more at: http://www.marylanddogmag.com/_articles/2014/spring/ask_the_vet.html#sthash.nyW1fDtJ.dpuf

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