April showers, bring May flowers. Most of us are familiar with this saying. But April showers also bring pollen and mold, and for those with allergies that means runny noses, puffy eyes, sinus pain, sneezing and headaches. For our pets, allergies can also be problematic. While their exposure can be from inhaled molds and pollens (allergens), pets absorb many of their allergens through their skin. The process of absorbed allergens to allergy response and symptoms is a complex one. Inhalant allergies, also called atopy, is a genetic tendency to have a heightened immune response to common, usually harmless, allergens. The important point to understand is that these allergens are harmless to those who are not allergic to them.
There are several features of atopy. It is typically seasonal, with spring and fall being the most common seasons. However, over time, the season for most pets increases and can become year-round. The onset of atopy symptoms in 70% of pets is in the first 1-3 years of life. The final feature of atopy is they respond rapidly to steroids. In comparison, food allergies are more variable and frequently do not respond at all to steroids.
The diagnosis of atopy is a clinical one, not based on testing. Symptoms in pets are primarily itchy skin. Dogs chew, lick or rub their feet, legs, around the eyes, muzzle, arm pits, ventral abdomen and anus. In cats, their pattern of irritation is not as characteristic and will mimic those found in several conditions. Twenty five percent of cats have more than one type of allergy. Genetically predisposed breeds include: Dalmatian, Golden Retriever, Labrador Retriever, West Highland White Terrier, Shar Pei, Dalmation, Cairn Terrier, Lhasa Apso, Shih Tzu, Boxer, and Pug. After a diagnosis is made, intradermal skin testing or serum antibody testing is used to find what your pet is allergic to. Intradermal skin testing involves shaving the area of skin, injecting small amounts of antigen and watching for a skin reaction, usually swelling or redness. Serum testing does not look for a direct skin response but measures antibody levels in the blood to specific antigens.
Once a diagnosis is made, there are several options for treatment. Many pets with allergies have secondary skin infections which need to be addressed at the same time. Secondary infections are either bacterial (Staphylococcus) and/or yeast (Malasezzia). These are normal organisms that live on the skin and penetrate deeper tissues because of damage from chewing and scratching. These secondary infections can further the allergic response and the prevent resolution of symptoms until they are addressed. Direct treatment options for the allergy include the following:
- Omega 3 Fatty Acids: Omega 3 fatty acids alone are not a treatment for allergies. However, increasing the amount of omega 3 fatty acids in your pet’s diet can decrease the production of inflammatory mediators and decrease the body’s reactivity. They take about 6 weeks to be effective, and their use can decrease the amount of other medications needed.
- Antihistamines: These can be effective in mildly affected patients. A 10-20% response is expected for any given antihistamine. Fortunately, there are many to choose from. Cats tend to respond better to antihistamines but sometimes they can be difficult to medicate orally. Antihistamines and omega 3 fatty acids are synergistic and help each other work better.
- Steroids: These have been the workhorse for the treatment of allergies for years. They work well in the short term to quickly and effectively control atopy. Steroids are started at a higher frequency and then tapered down to the lowest effective dose, usually every other day or every third day. They can have the short-term side effects of increased drinking, appetite and urination. Steroids can suppress the immune system and bring out latent urinary or upper respiratory infections. In cats, long acting injectable steroids are frequently used but can cause diabetes in susceptible cats. Short term use of steroids, less than 90 days’ worth in a calendar year, will have no long-term health effects. Long term side effects on the body occur in those patients where their atopy gets worse with time or those patients with year-round atopy.
- Cyclosporine: This is an immune modulator used commonly in organ transplants. Cyclosporine is a safe, effective and reliable treatment for atopy without the side effects of steroids. It has the down side of a 1-2 month onset of action, making it unsuitable for short term atopy.
- Oclacitinib: This is a relatively new treatment for atopy. Oclacitinib is a Janus kinase inhibitor that targets proinflammatory cytokines involved in itch and inflammation. It has a minimal negative impact on the immune system.
- Monoclonal antibodies: Monoclonal antibodies are designed to target a specific compound in the body. In this instance, the antibody targets a cytokine called Interleukin-31 (IL-31). This is the cytokine primarily responsible for itch and inflammation associated with allergies. By blocking IL-31’s effects, the allergy symptoms are minimized.
- Desensitization: Pets can be desensitized against their allergens just as people are. Once their allergens are identified, an injectable or oral vaccine can be made. These can take up 4 to 12 months to help. Fifty percent of patients will be helped enough to not require medication, 25% of patients will still require some medication during their worst time of year and 25% will not benefit. Allergy injections are tapered to once a month for life and oral vaccination is given twice a day for life.
Choice of the best treatment option should be a discussion between you and your veterinarian and be based on the severity and seasonality of your pet’s allergies.
Finally, reducing your pet’s allergen exposure can also help to reduce symptoms. Bathing weekly can reduce allergens on your pet’s skin. Pets with atopy have abnormal attachments between their skin cells allowing antigens to get in. Picture a brick wall where the mortar between the bricks is damaged and rain water can seep in. Using a therapeutic shampoo containing phytosphingnosine can help rebuild the skin’s natural barrier. Phytosphingnosine can repair the mortar between the bricks. Avoid stuffed toys and wash bedding regularly as this can decrease antigen exposure, especially for dust mites. Using an air conditioner and a filter system can also decrease exposure. Keeping pets indoors while mowing the lawn can decrease antigen exposure to grasses or other pollens churned up by the lawn mower.