By Dr. I Elizabeth Borgmann. During our first article on skin I talked about eliminating secondary skin infections as a step towards determining the underlying problem your pet may have with skin disease. In this article we will discuss skin infections, why they occur and how to treat them.

OK, why does a pet get a skin infection? Because the defence mechanism of the skin has been compromised! Yeast and bacteria live on the skin in low numbers because the skin has a host of ways to prevent infection. Something must happen to break down that mechanism.

There are skin infections that are simply due to a one-time event. For example, skin infections can occur after grooming too roughly, or after a run through the prickly bushes. In these cases there has been physical damage to the skin and it gets infected. And young animals are more likely to get a skin infection simply because their immune system is immature. Just like kids!

But what if the skin keeps getting infected? If skin infections become recurrent issues, there must be an underlying problem that is interfering with the skin defence mechanism. This might be allergies (food allergies or atopy), endocrinopathies (most commonly a low thyroid level), or immune mediated health problems. To get to the underlying problem, your vet needs to clear up the secondary skin infection first.

What do those infections look like? Take your pick! They could be smelly thickened ears, or feet. They could be pustules. They could be red rings in the groin. It could be flaky greasy skin on the back. And skin infections are itchy! Some pets will be more bothered by the infections than others.

How will your vet recognize that your pet has a skin infection? Well, some lesions are so obvious it’s like being slapped in the face. To confirm suspicions and to detect more complicated situations, your vet will take impressions of the skin, swabs, or scrapings and examine them under the microscope. This is done to determine if your pet has bacterial overgrowth (we like to call this BOG) or Malessezia (yeast) overgrowth (we call this MOG), or both. Yes, it’s not uncommon to have both!

Once your vet knows what they are up against, they will treat your pet for BOG, or MOG, or both. Here is what you really need to know! Treat for long enough!!

The number one reason treatment for bacterial and yeast overgrowth fails is that the treatment is not of adequate duration. Skin must be treated for at least 3 weeks, and sometimes up to 6-12 weeks to return bacteria & yeast to normal levels. The skin will start to look better much sooner than the bacteria & yeast are restored to normal levels. Treatment must continue a minimum of 7-10 days beyond the absence of clinical signs. Don’t stop treating your pet just because the skin looks ok!

In the event that the skin never responds and the infection does not go away, your vet may need to send a culture to the lab. Methicillin resistant
Staphylococcus infections do occur and if your pet is not responding to treatment your vet needs to take this a step further. Luckily, these resistant infections are not yet common.

Topical skin therapy through the use of special antibacterial or antifungal shampoos may be added to your pet’s treatment regime. This is often important if heavy scabbing is present.

So why do you need to clear up the signs of skin infection before you can get to the bottom of the skin problem? It simply complicates the situation. For example, is your pet itchy because of the skin infection or because of some other problem? You need to clear up the skin infection to see if the pet is still itchy. Is the thyroid level low because the body is trying to fight infection (euthyroid sick syndrome) or because the thyroid level is really low?

If it is determined that your dog or cat needs skin biopsies, then the pathologist’s job is a lot easier (and more accurate) if they are not trying to sort through two skin processes rather than just one.

It takes time and patience to get to the bottom of skin problems. The issue must be approached systematically. Sorry, no quick fixes here!
Next time, I’ll discuss ringworm (which isn’t a worm…it’s a fungus!). We see a fair bit here in our nice damp moist climate.

Dr. I Elizabeth Borgmann

Dr. Borgmann has been practicing in the Fraser Valley for over 11 years and can be reached at the Whatcom Road Veterinary Clinic