Food Allergies in Dogs and Cats

Food Allergies in Dogs and Cats

While food allergies are incredibly frustrating to diagnose at onset, treating them after diagnosis is very manageable. Learn how to ease the strain on your pet here.

Food allergies can be frustrating for you and your pet at first because the symptoms resemble so many other conditions. Food allergies affect dogs and cats across sex, age, and breed lines. Since diagnosis is the major obstacle to successful treatment, arming yourself with knowledge is the best way to reduce the potential impact of food allergies on your pet.

Causes of Food Allergies in Dogs and Cats

The most common food allergies in dogs are beef, dairy, chicken, wheat, eggs, corn, and soy. And for cats, the biggest culprits are fish, beef, and dairy. Food allergies in pets are caused almost exclusively by medium to large-sized proteins. Normally, the stomach breaks down food, and enzymes then disassemble proteins for proper digestion. When your pet’s body can’t properly break down a protein, it sets an immune response against the protein. Still, it takes at least two years of exposure to the allergen before your pet will show any clinical symptoms because each time your pet’s body encounters the allergen, the reaction becomes stronger.

Symptoms of Food Allergies in Dogs and Cats

By the time your pet’s body has built up a strong response to the allergen, both you and your dog will start to notice the symptoms. Your pet will get excessively itchy, especially around the head, neck, ears, hind legs, and anus. Because their skin feels itchy, your pet will start to lick and scratch, creating the awful cycle of pruritus, in which your dog’s skin deteriorates and becomes ever itchier simply because they’re scratching it. You may also notice hair loss, open sores, scabbing, and hot spots

While skin problems are the most common reaction to food allergies, you might also see your pet develop ear problems. Dogs, more so than cats, will sometimes develop ear infections and have red, swollen ear canals. Gastrointestinal issues like vomiting and diarrhea are the least common symptoms, so you may or may not see this sign in your pet, even if they do have food allergies.

Treatment for Food Allergies in Dogs and Cats

Because the signs of food allergies in dogs are exactly like the symptoms of inhalant allergies, flea allergies, skin allergies, or parasitic insect infestations, diagnosis can take a long time. Once diagnosed, you will have to find a food source that your pet has never eaten before. Because your pet needs 2 years to develop an allergy, eating entirely new ingredients will always be an effective treatment for food allergies. Some pet parents resort to home-cooked and fresh dog food during this food elimination trial period, but many commercially available products use limited ingredients with food allergies in mind. 

The trial diet should consist of an entirely new protein (often venison, rabbit, or fish) and an entirely new carbohydrate (peas or sweet potatoes, among others). If you’re home cooking, you should talk to your vet about a supplement to make sure your pet gets all of the necessary vitamins and minerals. A commercial pet food, however, will be complete with all the essentials. Your pet will need to stay on this limited diet for 6-8 weeks with no table scraps, no rawhide, no dog treats, or cat treats, no flavored toothpaste, no flavored medication, and no flavored plastic toys so that symptoms are guaranteed to subside.

When the trial diet ends, you can slowly introduce one food at a time at 2-week intervals. If your pet shows no reactions, then the ingredient is safe. If your pet does show symptoms again, you’ll know what’s provoking their allergies. Simply avoid the allergens you identify in the future, and you and your best buddy can return to happy, healthy, allergen-free lives.

This information is for informational purposes only and is not meant as a substitute for the professional advice, diagnosis, or treatment by, your veterinarian. Always seek the advice of your veterinarian or other qualified professionals with any questions you may have regarding a medical condition. Never disregard or delay seeking professional advice due to what you may have read on our website.

The Most Common Food Allergies in Cats and Dogs

Severe itching, especially around the head, may be a sign that your pet has developed an allergic reaction to food. Food allergies in cats and dogs can show up at any age, though they most commonly occur between ages two and six. Learn what types of foods dogs and cats become allergic to most often, and what to do when a change in diet is necessary.

Why Do Pets Become Allergic to Food?

Dog food sensitivity occurs when your pet’s immune system begins responding to certain proteins during the digestion process. After food is broken down in the stomach, enzymes go to work stripping proteins down to amino acids, which are then fully absorbed. However, there are specialized immune cells in the GI tract that will absorb more intact proteins and present them to the immune system as part of an “environmental survey” process. If the immune system is fooled, the body then views this protein as harmful, triggering your pet’s immune system, which starts to react whenever the offending protein is consumed.

This immune system dysfunction can occur shortly after the protein has been introduced to the diet or even after years of consumption. How the immune system is tricked is poorly understood.

Most Common Cat & Dog Food Allergies

In some cases, pets are allergic to more than one ingredient in the food. These cats and dogs are called atopic since they have multiple sensitivities. There’s likely a genetic component to their allergies.

  • Cats most often develop allergies to beef, seafood, and dairy products. They can also become allergic to any protein source that is in the offending food.
  • Dogs most commonly develop allergies to proteins in chicken, beef, dairy products, eggs, wheat, and soy. Much like cats, they too can develop an allergy to any protein source in the food.

You’ll recognize these ingredients in many commercial dog and cat foods. Allergies sometimes develop after a pet has eaten the same type or brand of commercial food for an extended period, so you cannot rule out food allergy just because your dog or cat has been eating their favorite food for a long time. There are special medications for atopic allergy called Atopica for cats and Atopica for dogs.

Symptoms of Pet Food Allergies

Reactions to food allergens include an itchy rash, bumps, scaly skin, swelling, hair loss, sores, hot spots, inflammation, and sometimes vomiting and diarrhea. Itchiness occurs predominantly around the head, neck, face, ears, feet, and under the armpits but can also affect the entire body. Your pet’s eyelids may become swollen, and you may notice your pet scratching constantly, shaking or rubbing their head, or licking their feet more often.

Diagnosing Dog & Cat Food Allergies

Food allergies can be tricky to diagnose, so it may take a long time to isolate the exact cause of your pet’s discomfort. Once your vet has determined that their symptoms are likely due to diet, an elimination diet may be suggested. This involves removing ingredients from your pet’s diet until symptoms are normalized, using limited ingredient diets from premium dog food brands. These diets are specifically made for these conditions and use single sources of ingredients like kangaroo and oats, or rabbit and peas.

Alternative Pet Foods to Try

After your cat or dog has been diagnosed with an allergy to a specific protein, commercial food may still be available for your pet. Hypoallergenic pet food that eliminates common food allergens is available. These dog allergy diets break the protein down into very small particles in hopes that your pet’s immune system will not recognize them.

Pay careful attention to the labeling of other commercial products and snacks. If your pet is allergic to beef, make sure to avoid foods and treats that have beef fats and beef proteins. Even monthly heartworm tablets made with beef flavoring can set them off! Also, look for specialized pet food like Hill's Science Diet’s Hill's Prescription Diet z/d Skin/Food Sensitivities Dry Cat Food and Hill's Prescription Diet z/d Skin/Food Sensitivities Dry Dog Food.

Some pet parents try serving home-cooked dog food to avoid extra ingredients. Be sure to go over any diet changes with your veterinarian or a board-certified veterinary nutritionist, and ask about supplement recommendations to ensure that your pet is still getting essential vitamins and minerals in their diet.

What foods are dogs and cats allergic to?

Food allergies in dogs and cats may happen at any age, even in pets eating a consistent diet for months or years. The unexpected part is that allergies can develop without changing your pet’s diet. The most common culprits of food allergies/reactions in dogs include beef, wheat, and dairy products. Cats can be allergic to beef, fish, and dairy products. According to Melissa Boldan, DVM and a graduate of the University Of Missouri College Of Veterinary Medicine, food allergies may happen when an overenthusiastic immune system reacts to a specific protein. It ends up treating the protein like a foreign substance and kicking it into gear, causing inflammation in the animal’s body. The response leads to reactions like swelling, itching, redness, and increased tear or fluid production. When the gastrointestinal tract produces extra fluid, it causes diarrhea and/or vomiting.

How do I tell if my dog is allergic to his food?

You can detect a food allergy in your dog by looking for symptoms such as itchy skin, paws, or ears. The animal may also experience digestive disturbances such as diarrhea or vomiting. Besides these evident signs, you may notice subtle changes like lack of energy, weight loss, hyperactivity, and even aggression. Statistics show that 20–30% of dogs with food allergies may also suffer from other allergies like atopic dermatitis or hypersensitivity to flea bites. These are other signs that ring warning bells for pet parents. According to the American Kennel Club, allergic reactions may not be visible immediately after a dog consumes a specific food. Some dogs develop symptoms within two months of eating the offending food, while others may get them after two years. 

How can I test my dog for food allergies at home?

An elimination diet trial is currently the only way you can diagnose a food allergy in your canine companion. Amy Fox, a veterinarian who graduated from Cornell University, notes that the elimination trial involves excluding certain common triggers from your dog’s diet to see if its symptoms improve over time. If you pay close attention, you will notice what works and what doesn’t when it comes to feeding your pet. Most vets recommend an 8-week test period when your dog must have only one food. This way, you can find the potential culprits and eliminate them from your pet’s diet to prevent food allergies in the long run. For example, if your furry friend is allergic to yeast, you can save it from developing yeast infections by eliminating yeast sources from its diet.

Can dog food allergies go away?

Unfortunately, there is no cure for canine (and feline) food allergies. Avoiding allergens is the best way to help them. That depends on finding out the culprits through elimination diet trials and steering clear of them altogether. At the same time, you can feed your pet a hypoallergenic diet. You can easily get specialized prescription diets for dogs with food sensitivities to help your pet get the right nourishment without risking allergies and intolerances. These tailored formulas support sensitive stomachs, prevent digestive upsets, and maintain canine immune systems. Some dogs may need medication during severe episodes. Taking your pet to a vet is important if the allergy seems to make it uneasy and sick. 

How can I tell if my cat is allergic to his food?

Food allergies are rarely found in cats. PetMD states that only 1% of these animals have food allergies, which means most cat parents do not have to deal with them. According to Andie Lenhard, DVM, and RN double licensed, cats and dogs with allergies commonly show symptoms like itching, skin problems, fur loss, and red, moist spots. Other signs of food allergy in cats include vomiting, diarrhea, difficult bowel movements, ear infections, sneezing, coughing, wheezing, and discharge from the eyes and nose. If you see one or more of these red flags, schedule a visit to the vet as soon as possible. The sooner you get an allergy test, the less your feline companion suffers. 

At what age do cats get allergies to food?

Cats are usually allergic to protein sources like fish or chicken. Since these pets are most likely to be exposed to the offending allergen as they grow older, most of them encounter food allergies between the age range of 2 to 6 years. In most cases, allergy signs appear only when your cat eats the food culprit every day. However, there are exceptions, as a cat may develop an allergy at any point during its life, even to a food or ingredient it has always been eating for years without any issues. That’s the reason you should watch out for symptoms indicating that something is amiss. 

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