Veterinary Acronym of the Month - FAD

Flea Allergy Dermatitis and other things that make your pet scratch

Nobody likes it when their pet is scratching. From mild itching to raw skin from continuous irritation, skin disease can present a serious problem for pets and owners.

I typically approach itching pet cases with three main causes in mind - parasites, environmental allergies, and food allergies. While there are many contributing factors, I like to break it down into these three main categories to make it a bit more manageable for everyone involved.

Parasites

When I first mention parasites, most people think fleas. To be fair, the vast majority of cases that come in with itching are due to fleas, hence the title of this post. These bugs are small and fast making it really hard to catch them in the act of terrorizing our pets. Most of the time, even us veterinary professionals don't see them on examination. In these cases, we search for evidence they've been there - most commonly, this is flea dirt. Dark brown or black specs through the fur that turn a reddish brown when wet. (Flea dirt = flea poo, if you didn't know). Other signs are small scabs, usually over the base of the tail or around the neck. I always remind owners that it only takes one flea bite to cause a serious itch reaction, especially in pets with an allergy to fleas - this is where the term flea allergy dermatitis came into play.

Essentially, derm = skin, itis = inflammation. All-in-all we end up with inflamed skin secondary to an allergy to fleas. Simple enough, right? Well, no. This irritation leads to scratching and scratching leads to damage to the skin surface. This allows bacteria to enter the skin, leading to infections and further discomfort. Did we mention that fleas drink your pets blood? Severe cases of flea infestations can lead to anemia, or a lack of red blood cells.

So now what? Of course, as we've mentioned in numerous previous posts, we recommend year round flea, tick, and heartworm prevention. Talking with your veterinarian to determine the best option for you and your pet will help reduce the risk that your pet is even exposed to fleas. What about your pets who never go outside? We recommend treating them too. It's easy to carry fleas into the home on our clothing and other pets who go outside can easily bring them in as well. Once they're in, it takes 3 consecutive months of treating all furry animals in the home along with heavy vacuuming and laundering of bedding to rid the home of fleas. While there are products out there to treat your space, some are not safe for pets, so we strongly recommend reading labels carefully and contacting a professional exterminator for guidance.

That first paragraph made it sound like there are other parasites out there causing itch that aren't fleas and you would be correct. While they aren't causing FAD specifically, different mange species can cause skin disorders, itch, hair loss, etc. These are microscopic parasites that can be seen with certain tests performed by your veterinarian. Many of the prescribed flea/tick preventatives available through your veterinarian will treat them.

Environmental Allergens

This category seems fairly self-explanatory. These are the same allergens that plague us humans - grasses, molds, pollens, mildews, etc. This category can be frustrating because, like our next category, it isn't as easy to test for. There are blood tests available to evaluate an animal's sensitivity to different allergens, however there has yet to be a test that is both sensitive and specific enough to be entirely reliable. Essentially, it is out there, but the results are not always accurate. For owners interested in knowing exactly what makes their pet itch, I recommend referral to a dermatologist for skin testing, just like we do in people. This is the most reliable testing we have available as of now and is performed by a specialist who will make tailored recommendations for your pet.

That is not to say that there is no hope if you don't pursue a referral appointment. A majority of environmental allergens will have a pattern to them. Usually they appear seasonally if they are outdoor allergens (particularly here in Upstate New York where we have varying temperatures and plant growth throughout the year). Most commonly we will see that pets show itchy feet, ears, eyes. Some pets will have an allergy to something specific they came into contact with, such as laundry detergent, and may show irritation where they touched the allergen.

Treatment options vary. For dogs, we have a few different medical management options. These can include medicated shampoos used regularly as directed by your veterinarian to removed topical allergens and help build the skin barrier. It may include Apoquel, an oral medication used to tell the body not to create an itch response, or Cytopoint which is an injection given once every 6-8 weeks that works in a similar manner. Both have side effects that should be discussed with your veterinarian prior to pursuing. Hill's Science Diet released a prescription diet not too long ago that is meant to replace the need for either of these medications. The diet should be the sole food fed to pets, though they can have hard boiled eggs as a snack if your veterinarian agrees. We have seen this benefit pets with both environmental allergies as well as mild food allergies.

Cats have fewer options, as is the theme through veterinary medicine. We do use Atopica, a version of cyclosporine that is meant to reduce itching in cats. Additionally, steroids are occasionally used for pets, though this practice seems to be falling out of favor as a general statement. Again, side effects should always be discussed with your veterinarian prior to pursuing any medications.

Food Allergens

The final category I divide my itchy pets into is the food allergen category. Despite a societal trend of blaming grains for allergies in pets (see my post on choosing a diet for your dog), the most common food allergens are actually chicken and beef. Yes, they are also of the most common ingredients found in dog food. So what is one to do?

Sure, there are diets out there for sensitive skin and stomachs, and some of them really do help pets with mild sensitivities. That being said, a true food allergy requires a hypoallergenic diet. These diets are cooked in a way that denatures their proteins, essentially making it so that when they are digested they don't cause inflammation. These are by prescription only and should be the only diet fed to a pet with food allergies. This means no outside snacks, treats, or table scraps. It takes 6-8 weeks to see an effect from changing to a hypoallergenic diet, so many vets will prescribe medications to help keep pets comfortable during that transition. Why prescription? They're made in special facilities to ensure no cross contamination of products to keep your pet safe and they're guaranteed to meet nutritional requirements.

So you mean to say that food allergies can irritate the skin? Sure can. Most dogs with food allergies will have itchy feet, recurrent ear infections, recurrent skin infections, and anal gland irritation. Cats can show similar discomforts, though many of their signs are commonly missed (because they're sneaky ninjas, it's what they do). They are more likely to show signs of intermittent vomiting, diarrhea, weight loss, which dogs can also show when they have food sensitivities.

As I mentioned a few times above, it's important for your veterinarian to examine your pet to help identify causes of irritation, treat any secondary issues like those pesky bacterial infections, and develop a plan for allergy management moving forward. In many cases, we may approach all of these aspects at one time by starting flea/tick prevention (after all, we do recommend all appropriate pets be on year round flea, tick, and heartworm prevention!), a medical option to control itch while treating the underlying problem, and considering a diet trial with one of the prescription hypoallergenic diets. Once a pet is well-controlled, we may try discontinuing a medication to see how they respond or testing small individual foods to see how a pet tolerates them. It is essential that a veterinarian be involved throughout this process to monitor response and determine when to make changes.

With temperatures rising and pollen blowing in the breeze, we sure are seeing more itchy pets lately! If you notice your furry friend licking and chewing at themselves, we recommend you give us a call to schedule an appointment and talk about treatment options!