Dog Allergies - Food or Seasonal?

If you suspect that your dog’s daily roll in the grass causes allergic reactions, such as excessive paw licking and rigorous belly scratching, you may be surprised to learn that he could actually have a food allergy.

While it’s common for dogs to suffer from seasonal allergies to things like the pollen they come in contact with while playing in the yard, several types of dog allergies can manifest themselves in similar ways, said Dr. Sarah Nold, an on-staff veterinarian for Trupanion, a Seattle-based insurance company.

“Food allergies and environmental allergies can cause similar symptoms. These symptoms can include itchiness, hair loss, skin infections and ear infections. In addition, other conditions can cause similar symptoms. This is why your vet may need to start with diagnostics to first rule out skin mites, fungal infections and endocrine diseases, such as hypothyroidism and Cushing’s,” Nold said.

Dr. Joseph Bartges, a veterinary nutritionist and professor of medicine and nutrition at the University of Tennessee’s College of Veterinary Medicine, said that seasonal allergies typically occur during certain times of the year while food allergies have no seasonality.

However, they do overlap, and approximately 30 percent of pets with the food-responsive disease also have seasonal allergies or allergies to fleas, he said. Many of these allergies present themselves either with skin problems (like itchiness, recurrent infections, ear infections or hair loss) and/or gastrointestinal signs (like vomiting, diarrhea or decreased appetite), he added.

Since many of the signs and symptoms of allergies in dogs are not unique to either type of allergy, treatment may require a bit of educated trial and error to pinpoint the exact cause of your dog’s allergy. A visit to your vet should always be your first step. Here are some general guidelines to help dog owners understand food and seasonal allergies.

Symptoms of Food Allergies

Many owners may not immediately suspect their dog has a food allergy because it can take years for their dog to develop an allergy to the food it is fed every day. Food hypersensitivity can occur at any age in a dog’s life.

Dr. Patrick Mahaney, a holistic veterinarian, says one possible indicator of a food allergy can be the location of the skin problems. “If you notice lesions all over your dog’s body, on the flanks, ribs, hips or knees, there’s a big chance it’s a food allergy,” he said.

Other symptoms include recurrent ear infections, vomiting, diarrhea and itchiness that can lead to self-trauma such as hair loss, scabs or hot spots (areas that have been repeatedly licked or chewed and have become inflamed). Gastrointestinal issues are usually symptoms that are specifically related to possible food allergies.

Diagnosis and Treatment of Food Allergies

Your vet will likely want to start with a review of your dog’s dietary history. It’s important to include the foods that make up his daily meals as well as any treats. Many dogs are allergic to chicken, dairy, beef, eggs, corn, soy and wheat, and some of the additives contained in commercial brands of dog food.

Bartges says your vet may suggest eliminating certain proteins and substituting them for a novel protein, or a protein source that the dog has not been exposed to, such as duck, fish or kangaroo. Other options include a hydrolysate diet (where the protein source has been pre-digested to small pieces that are too small for the immune system to recognize) or a homemade diet of either cooked or raw food.

It can take a few months to see an improvement in your dog’s food allergies, Nold said, but it’s important to diligently stick to the prescribed diet and completely eliminate any treats and table scraps. Even certain medications can be flavoured, Nold said, so make sure to discuss all medications your dog may be taking with your veterinarian to ensure they’re an approved part of the diet.

If your dog does well and shows no signs of an allergic reaction, you can gradually add other kinds of food. But if he shows no sign of improvement, regardless of the food source, it may be time to consider that he could be suffering from a seasonal allergy.

Symptoms of Seasonal Allergies

Seasonal allergies generally occur at certain times of the year. Some of the common causes of seasonal allergies include dust,

dust mites, pollen, grass and flea bites. Mahaney said that lesions on the top or underside of your dog’s feet often point to environmental allergies.

Your dog’s climate and environment can have a major impact on if they have seasonal allergies or not, he said. “In Los Angeles, for instance, it’s always warm, so things are blooming year-round, which can expose your dog to more allergies. But in New Jersey, things bloom in the spring, and then they’re gone in the winter.”

Regardless of where your dog lives, it’s still possible for him to develop year-round allergies.

“Allergies can occur at certain times of the year, but they can turn into year-round allergies for older dogs. The more your dog is exposed to the allergens he’s sensitive to, the more intense and long-lasting his allergic response becomes,” Nold said.

Diagnosis and Treatment of Seasonal Allergies

There are many ways that seasonal allergies can be diagnosed and treated, most of which depend on the allergen. These include:

  • Testing: an intradermal skin test, in which a small number of test allergens are injected under your dog’s skin, can help pinpoint the problem of moderate to severe allergies. Allergens are identified by which injections cause redness, swelling or small hives. Your vet can then create a specialized serum or immunotherapy shot, which can be administered at home or in your vet’s office. Nold says 70 percent of dogs have good results after a year of shots.
  • Fatty acids: omega-3 fatty acid supplements like fish oil can help reinforce the skin’s barrier, reduce inflammation, and can be helpful for all types of allergies in addition to chronic issues including skin, joint and cardiac problems.
  • Antihistamines: the same over the counter antihistamines that people take can be given to dogs to help reduce itching. Depending on the dog and his condition, however, it can take some time and effort to find the right one. “I’ve seen owners give their dog Benadryl because it helped their friend’s dog, but it won’t be effective if your dog has developed a secondary skin infection,” Nold said. “It’s always a good idea to consult with your vet before giving your dog over the counter drugs, so you don’t make things worse.”
  • Steroids: dogs who are severely itchy and uncomfortable may need a steroid, which can quickly reduce itching. But owners should be aware that there are increased side effects of steroid medication, such as high blood pressure and kidney disease. Your dog should receive regular blood and urine testing if he is taking steroids on a long-term basis.
  • Antibiotics: Your vet may prescribe antibiotics if your dog’s constant licking, chewing or rubbing has created a secondary skin infection. His skin may look red and inflamed or have a circular bald patch with a crusty edge.
  • Environmental control: Mahaney said simple things like preventing your dog from making contact with known irritants could go a long way toward providing relief. “Don’t let your dog go on specific surfaces that irritate him like grass. You may have to make a lifestyle change. If you can’t rip out your grass, try putting boots on your dog. Or give him a localized footbath or a cleansing foot wipe down. It may also be a good idea to keep your dog on a regular bathing schedule, which can help remove abnormal bacteria,” he said.
  • Flea control and prevention: It’s common for dogs to have an allergic reaction to flea saliva, which can cause itchy spots and red bumps toward the back end of his body. Ridding your dog of a pesky flea infestation can be a difficult task. Make sure to apply flea preventative medication as directed by your veterinarian, as improper use of flea and tick medication can result in an infestation. Other ways to help keep the flea population down include regularly vacuuming carpeted surfaces, using a flea comb and washing your dog’s bedding weekly with hypoallergenic, non-toxic detergents instead of household cleaners that may contain chemicals.

Overall, getting to the root of your dog’s allergy can take a bit of educated detective work. The most important thing is to seek help from your vet and not to get discouraged with the process.