Even after all these years, I am still surprised when owners comment that “I didn’t know that pets had allergies” or “I didn’t know pets could develop diabetes”. While pets are not little people in fur coats, dogs and cats are physiologically very similar to humans and can succumb to most of the same illnesses and disease processes that we do. One such condition is allergies, which account for a large proportion of visits to the veterinarian.
Allergies occur when our immune system hyper-reacts to something that isn’t truly a threat. The immune system is our body’s day-to-day defense against anything that is unfamiliar, such as infectious agents (microorganisms, like bacteria and viruses) and parasites. Most of the time, our immune system does an excellent job of keeping us healthy and preventing infection and disease. However, sometimes our bodies mount an exaggerated response to substances in the environment, termed allergens, that are typically viewed as harmless. That response can range anywhere from an annoyance to a life-threatening medical emergency.
Dermatological reactions, otherwise known as skin-based allergies can manifest as itchy skin (pruritus), skin infections (dermatitis/pyoderma), and ear infections (otitis). While these are not immediately life-threatening, skin allergies can certainly be life-compromising and negatively impact your pet’s comfort, long term health, and quality of life when left untreated.
There is a misconception that allergic reactions to food are the mainstay of allergies in dogs and cats. While food allergies do exist, allergies to external parasites like fleas and environmental allergens like pollen, grasses, and dust mites are far more prevalent.
Many cats and dogs are allergic to fleas. In fact, FAD is the most common skin disease in dogs in the United States. Flea allergies often spike in the summer; however, in warmers, and especially humid, climates, FAD can be present throughout the year. Everyday itching from a fleabite isn’t the same thing as a flea allergy. In FAD, your pet’s immune system is reacting to components in the flea saliva and the degree of pruritis is often more intense and longer-lasting. Signs may include constant itching, biting, clawing, or over-grooming, which may result in a rash, papules or pustules, or raw, irritated and bleeding areas on your pet’s body (sometimes termed hotspots).
Dogs often mount their most intense reactions from the mid-back to the base of the tail, as well as on their thighs and underbelly.
Cats are more likely to manifest their reactions near their neck and face or may develop tiny little scabs along their entire back, known as military dermatitis.
Many pets that have seasonal allergies (atopy) are more likely to have an allergic reaction to fleabites as well, creating an overlap in symptoms, which can make the diagnosis of allergic triggers challenging.
Atopy (atopic dermatitis) occurs when your pet’s immune system over-reacts to commonplace and typically innocuous substances in the environment. While some breeds are pre-disposed to atopy, environmental allergies can be diagnosed in any cat or dog. In pets, the most common symptom of allergies is itchy skin (pruritus), which can be localized to certain areas of the body like the feet, flanks, ears, and inner thighs, or can be generalized (the whole body).
When pets scratch and chew in response to their itchiness, small abrasions and sores are created, increasing the risk of bacterial and yeast infections, which further exacerbates the itchiness, establishing a vicious cycle. Typically, the bacterial and yeast infections arise from the commensal populations of microorganisms that normally inhabit our skin. When our skin’s barrier is compromised, this normal population has an opportunity to over- multiply, creating an infection. This can occur on the belly, in the ears, between the toes, on the face…wherever there is skin, irritation is possible.
While dermatological signs are most prevalent, some cats and dogs will manifest their allergies with respiratory symptoms like sneezing, watery or irritated eyes, or coughing, like we see more commonly in humans. Other pets may react to the allergens with gastrointestinal upset, which may result in vomiting and diarrhea. Some animals, unfortunately, may experience allergic symptoms in all the aforementioned categories.
With food allergies, your pet is reacting to a certain component of the diet being consumed. Common symptoms of food allergies include recurrent ear infections, itchy rear ends, and chronic GI upset and gas. While food allergy is less common than the other instigators of allergic dermatitis, we do find that manipulating a pet’s diet can be a very useful tool in managing their symptoms. Many times, animals that have environmental allergies may also have food allergies and/or food sensitivities, and those symptoms can overlap.
When we consider making a dietary transition in an attempt to control allergic disease, we often reach for a novel protein or elimination diet. What this means is seeking a protein source that your pet has not previously eaten or been exposed to in their diets or treats – hence offering them a novel, or new, protein in their diet. For example, if your pet has been eating a beef formula, you could consider transitioning to a fish-based or lamb-based diet. If your pet’s skin condition improves, you can assume that your pet may have been reacting to the beef ingredient. Of course, we all know that we are not operating in a vacuum, so these are just assumptions not diagnoses. Elimination diet trials take time and patience. You may need to systematically eliminate different ingredients over time, but when you have identified the offending ingredient, the results can be excellent.
Regardless if your pet has allergies or not, the quality of your pal’s diet has huge impacts on her skin and coat health. Feeding a diet that is balanced, that offers sustainably-sourced high quality meat proteins, that is free of additives and artificial flavoring or coloring, and that provides an appropriate ratio of omega fatty acids can benefit your pet’s dermatological health and health in general. Probiotics also play a very important role in helping maintain a healthy balance of “good” bacteria, both in your pet’s GI tract and skin.