ALLERGIES: When the Itch Strikes, Strike Back!
Having an itchy pet can be a frustrating ordeal for not only the pet, but also for you, the owner. And when a pet has multiple episodes of itchiness or has been itchy for a prolonged period, it's important to not only stop the itching, but to understand why the itching occurred in order to hopefully prevent future outbreaks.
A few key points to remember are:
- Scratching is not the only sign of itchy skin. Other signs include rubbing, scooting, biting, chewing & licking.
- There are MANY things that can cause a pet's skin to itch, but the skin can only react in a limited number of ways so a lot of skin issues look the same to the naked eye.
- In most cases we have to treat secondary infections (bacteria +/- yeast) before treating or perhaps even diagnosing an underlying cause. This is because there are normally a small number of bacteria & yeast that live on skin. When the skin becomes inflamed, it sets up a perfect environment for these organisms to multiply & cause an infection.
- Following a systematic approach to reach a diagnosis will minimize time, expense & frustration later on.
- The ears are an extension of the pet's skin. A pet that gets multiple ear infections, even if only one ear is involved, most likely has an underlying disease such as allergies. In fact, in 20% of dogs with allergies, the only clinical sign they have is ear infections.
- Simple dry skin as a cause of itching isn't nearly as common as it once was as most pet foods are formulated to contain at least a modest amount of essential fatty acids and most commercial pet shampoos are pretty mild. That being said, if you're using a harsh soap or chemical based shampoo (many flea shampoos are harsh, as is Dawn detergent), you will likely want to stop & get a recommendation from your veterinarian for something that won't contribute to dry skin.
So if your pet has itchy skin, what could it be? Most often, itchy skin is the result of either bugs, hormones, allergies, or rare autoimmune or mineral deficiencies. Bugs consist of fleas, ticks, lice, mange, fungi, bacteria & yeast. Although some can be seen with the naked eye, most of the bugs require microscopic identification, culture, or even a treatment trial to rule them out. But because these organisms are among the easiest to diagnose and are most likely to result in a complete cure, they should be ruled out before pursuing other more aggressive (and often costly) tests.
Some hormonal skin diseases like hypothyroidism, a condition seen in some dogs, can be diagnosed relatively easily via bloodwork. However, the treatment is to administer a thyroid supplement indefinitely resulting in control of the condition. Routine labwork is required to ensure appropriate thyroid levels are being maintained.
Allergies, which can be the most frustrating of all the skin conditions, can be divided into 3 types: flea, food, and atopy (allergies to things in the environment):
Flea -- This is the most common form of allergy, but it's important to remember that you may not see the fleas! For flea allergic pets, even the bite from a couple fleas is enough to cause intense itching (think of the person allergic to peanuts or bee stings!). Fleas are such quick critters living so close to oftentimes dark colored skin, it's easy for a couple to be overlooked. For these poor pets, strict year round flea control with a safe, effective, fast acting product is the key.
Atopy -- The second most common form of allergy. Atopy is allergies to things in the environment like pollens, grasses and dust mites. Initially, it was thought these allergies were inhaled by the pet. However, we now know that the allergens (protein substances the pet's immune system reacts to) enter the pet's skin through breaks in the protective lipid or oil barrier. The diagnosis of this disease can be by exclusion of other diseases, blood testing = serum allergy testing, or most accurately through intradermal skin testing. Historically, the intradermal skin test, usually performed by a veterinary dermatologist, has been considered the “gold standard”, though the serum testing has gotten increasingly accurate. Because serum testing is almost as reliable, it can be performed by most general veterinarians and its results can be used to formulate injections or oral medications to try and desensitize the pet to the allergens (which is especially useful if the allergens cannot be avoided, the pet's itching is really intense or the owner doesn't want to simply give the pet oral medications long-term with no attempt at cure).
Food -- Lastly, some pets suffer from food allergies. In order to diagnose this, a very strict hypoallergenic diet trial must be performed for a minimum of 8-12 weeks. In many cases we will rule this out prior to diagnosing atopy, although pets that have an allergy to one thing are more likely to be allergic to multiple things.
Some skin conditions fall outside of those listed above -- the zinc dermatosis, autoimmune disorders, and some hormone imbalances -- and will require a skin biopsy for diagnosis. Fortunately, however, these conditions are rare.
Understandably, an itchy pet can be frustrating. But if a plan is developed early on, everyone commits to following through with it, and following up with rechecks (which are crucial to not only resolving secondary infections but determining underlying causes), the entire process will go much smoother for everyone!