FOOD ALLERGIES IN DOGS & CATS

FOOD ALLERGIES IN DOGS & CATS

 

A food allergy is a reaction by an individual animal to a particular substance in their food. This occurs when the bodies’ response to normal food becomes ‘confused’, causing abnormal reactions. Frequently the food has been part of the diet for a long time. We cannot stop this abnormal reaction so the only effective treatment is to avoid eating the food that causes the problem.Food allergy is one of the itchiest conditions known to cats and dogs. Animals eat a variety of processed food proteins, flavorings, and colorings that are further processed inside their bodies. Proteins may be combined or changed into substances recognized by the immune system as foreign invaders to be attacked. The resulting inflammation may target the gastrointestinal (GI) tract or other organ systems, but in dogs and cats it is the skin that most often suffers from this immunologic activity. Cats itch around the face or neck which produces scabs and hair loss.

Dog food is one culprit behind allergic reactions in dogs that owners often overlook — it’s easy to attribute the itching or licking to an environmental factor that causes skin allergies. Just like us, canines can suffer from food allergies and intolerances. Food allergies in dogs can be very serious and cause not only digestive problems like vomiting and diarrhea, but also skin issues, and even behavioral problems.Food allergies occur when your pet’s immune system mistakes a food protein as an invader and initiates an immune response. This immune response can cause itching, infections, vomiting or diarrhea.A food allergy occurs when your dog’s immune system mistakenly identifies a particular food ingredient (usually the protein source) as harmful. Your dog’s body then creates defensive ant ibodies to fight the invading enemy (the ingredient).

Dog Food Allergy Symptoms

Sneezing. Ear infections. Chronic Diarrhea. Restlessness. Dog food allergy symptoms run the gamut from skin reactions to gastrointestinal troubles to behavioral issues. Below you’ll find a full list, broken down by category, to help you identify whether your pup might be suffering from a food allergy or intolerance.

Most Common Signs of Food Allergies in Dogs

These are the signs you’ll see most often with a food allergy, starting with the single most common symptom: itching.

• Itching (aka pruritus)
• Sneezing
• Itchy paws
• Hot spots
• Skin rashes
• Scaly and/or oily skin
• Pigmented skin
• Leathery skin texture
• Eye discharge
• Red eyes
• Hair loss
• Ear infections
• Secondary yeast or bacterial infections (aka pyoderma) of the skin or ears

Gastrointestinal Food Allergy Symptoms in Dogs

According to Shmalberg, only 10 to 30 percent of dogs with confirmed food allergies have gastrointestinal, or GI, symptoms like vomiting or diarrhea. “This is a condition that is much more often linked to skin symptoms,” he explains (see above). “Sudden and short-lived GI symptoms are almost never caused by a food allergy. On the other hand, food allergies can contribute to or cause certain chronic symptoms.”

• Diarrhea with or without blood and/or mucus in stool
• Straining to pass stool
• Vomiting
• Abdominal pain

Rarer Symptoms of Food Allergies in Dogs

These symptoms aren’t as common as those above but may occur in some dogs.

• Nasal discharge
• Breathing issues
• Seizures (food allergies could trigger them in predisposed dogs)
• Secondary urinary tract infections (due to overgrowth of skin bacteria)
• Weight loss (in combination with severe diarrhea and/or vomiting)

Dog Behavioral Issues from Food Allergies

The symptoms below are also rarer, and usually secondary to or linked to discomfort from symptoms listed above.

• Frequent scratching of self on furniture, owner’s legs, etc.
• Restlessness
• Frequent shaking ears or scratching ears
• Biting at paws, rear end, and/or tail
• Withdrawal or reduced interest in playtime
• Anorexia, or disinterest in or refusal of food

Some pet owners wonder if their dogs can inherit allergies, and the short answer is yes. Essentially, they inherit the allergy from a parent and if they’re exposed to that food, they’ll have an allergic reaction as well.Dogs are most commonly allergic to the following foods (in descending order): beef, dairy, wheat, egg, chicken, lamb/mutton, soy, pork, rabbit, and fish. Rabbit and fish are by far less common food allergens than the others.

  

Most Common Dog Food Allergens

“Meat, dairy, and eggs are often thought to be the most common dog food allergens,Yet generally, it’s the protein part of those foods that tend to be problematic, rather than, say, the meat itself.” Keep in mind, veggies can contain protein, so they’re not automatically safe.

Top Dog Food Allergens (source: BMC Veterinary Research)

Dog Food Allergen	Percentage of Dogs With Reported Reaction
Beef	34%
Dairy Products	17%
Chicken	15%
Wheat	13%
Soy	6%
Lamb	5%
Corn	4%
Egg	4%
Pork	2%
Fish	2%
Rice	2%

 

Two important caveats to keep in mind here.

1. Newer research is needed.
   Many of the studies out there, and those sourced in this review, are older, when dog foods were being made and processed differently than they are today. Allergies tend to change over time along with foods, and as new studies emerge, we may see different allergens rising to the top of the list.
2. The more common a food is, the more likely the allergy.
   For an allergy to a food to develop, a dog needs to be exposed to that food.That may explain why the proteins most commonly found in dog food, like beef and chicken, fall higher on the list.

More facts about dog food allergens that are helpful to know:

• Starches are safer.
  Pure carbohydrates, aka starches, are pretty low in or free of protein, which means dogs usually aren’t allergic to them. There are exceptions: while potato starch is probably safe, whole potatoes might cause an allergy because they contain proteins. Same goes for higher-protein grains like corn and wheat. But overall, grain allergies are much less common than meat allergies.
• With fats, purity matters.
  Pure fats, like fish oil, are free of protein and shouldn’t trigger a response. But traces of protein can sneak into oils and fats during processing, and in a highly allergic dog may cause issues.
• Look out for gelatin.
  Supplemental oils often come in gelatin capsules, and that gelatin can trigger allergies in some dogs.
• Peanut allergies are rare in dogs.
  And if they do occur, they typically aren’t of the severity reported in some humans. Good news if your pup is one of the many who love a PB treat!
• No two foods are exactly the same.
  There’s not a good deal of evidence to suggest that a dog who has a reaction to one food will also react to a similar food. That is, a dog allergic to chicken won’t necessarily be allergic to turkey.
• Watch for additives.
  Chemicals, preservatives, colorants, and palatants aren’t likely to cause a true allergy, but they could trigger an adverse reaction or intolerance symptoms.
• Food labels don’t always tell the whole story.
  Some non-fresh kibble and canned foods have tested positive for proteins even when they’re not listed on the label.

  

7 most common causes of food allergy in dogs

1. Proteins are common food allergens. Feeding your dog a single food for years increases their potential to develop an intolerance or allergy to one or more ingredients. Beef is one of the most common ingredients in a lot of pet foods, which may be the reason it’s the most common food allergen. I feed our three dogs a raw diet and we rotate meats every week. I do this partly to ensure we decrease the risk of developing a food allergy.
2. Some dogs have problems digesting lactose. This is an intolerance, rather than an actual allergy. Lactose intolerance leads to gas, diarrhea, or vomiting. What’s tricky is that a true dairy allergy can lead to these symptoms too, so it’s hard to know if a dog is suffering from an allergy or an intolerance. One important distinction: a dairy allergy may manifest as skin itchiness or related symptoms, whereas lactose intolerance is always about digestion.
3. There are many misconceptions regarding carbohydrate-containing foods for dogs, especially grains. It’s much more common for dogs to have allergies to meat than grains, for instance. However, some dogs do have an allergic reaction to wheat. Check with your vet or pet nutritionist about grains, as every animal should be treated as an individual.
4. An egg allergy means that your dog’s immune system overreacts to the proteins present in the egg yolk. Fortunately, it’s relatively easy to avoid eggs. Just be sure to double-check food labels.
5. The same rules apply here as they do for beef and lamb! Just because it’s plain old chicken doesn’t mean your dog can’t be allergic to this common protein.
6. Many commercial dog foods were made with chicken or beef, so lamb was considered a good option for dogs that experienced allergies while eating “regular” food. However, it’s also a possible cause of allergy. If your dog is allergic to lamb and rice, you could try venison and sweet potato.
7. Some studies have shown that eating soy can cause various health issues beyond allergy, including reproductive and growth problems, thyroid, and liver disease.

Breeds prone to food allergy

While there isn’t any scientific literature on which breeds are most susceptible to food allergies, the following breeds are the most commonly googled along with the search term “food allergies” or “dog food allergies”.

• Dachshunds
• Bulldogs
• Golden Retrievers
• German Shepherds
• Pugs
• Pitbulls
• Cocker Spaniels
• Shih Tzus
• Westies (aka West Highland White Terriers)
• Yorkies (aka Yorkshire Terriers)

Food allergy testing for dogs

If you suspect your dog is suffering from a food allergy, the first thing to do is talk to your vet about how to pinpoint the allergen. There are commercial skin and blood allergy tests on the market, and your vet may recommend starting there.

Dog Food Allergy Test and Other Diagnosis Methods

So, how can you tell if your dog is allergic to food?

First, it’s helpful to know how you might distinguish a food allergy from an environmental one. Environmental or flea allergies are far more common.If you suspect either of those, consult your vet, who can help identify and treat fleas, or do a combination of blood tests and/or intradermal allergy testing (which involves injections of potential allergens under the skin) to assess environmental allergies.

But if your dog has the following signs, talk to your vet about setting up an elimination diet trial.

 

Telltale Signs Your Dog May Have a Food Allergy (vs. an Environmental or Flea Allergy):

• If the symptoms occur at a very young age—typically, puppies younger than age 1 don’t experience environmental allergies
• If the symptoms aren’t tied to a seasonal change or don’t change in different parts of the country (e.g. if you travel or move with your dog from a dry climate to a humid one)
• If the reaction doesn’t respond to steroids
• If your dog has both skin and gastrointestinal symptoms

 

Dog Food Elimination Diet

The most reliable way to diagnose a food allergy is to feed your dog something entirely new, and relatively pure, for at least eight weeks. For accurate results, you’ll need to feed a non-contaminated simple ingredient diet (it can be commercial or cooked) for the entire trial. Most importantly, the diet should include a single-source animal or vegetable protein and a single source of carbohydrate calories, without other natural flavors (that could have unidentified proteins)—and it must be a food your pet hasn’t had in the past. Classic examples include venison and potato, rabbit and pea, and fish and potato.” There are newer options out there too, like alligator and coconut.

It’s also important you refrain from feeding treats, table scraps, snacks, and flavored medications and supplements of any kind that don’t match the specific ingredient combo you’re using for the trial. After at least eight weeks, to truly prove the food allergy, you must then feed the original food—the suspected allergic protein or proteins—again. If there’s a reaction or breakout at that point, that’s a pretty good indication of an allergy.

The reality is that most owners don’t complete this part, as they don’t want their dog to have symptoms again,An owner might just continue to feed the trial food if it seems to be agreeing with the dog.” But reintroducing the suspected allergens is really the only way to confirm an allergy. We suggests cycling through potential allergens one by one—chicken, beef, egg, dairy—to see what does (and does not) trigger symptoms.

Other Types of Dog Food Allergy Testing

Aside from elimination diets, there are a couple of other test options worth a look.

• Blood tests:Blood tests exist, but they’re not very accurate. “There are new food allergy blood tests in development, which appear better than those on the market,That means, for now, a food elimination diet is the best option.
• Patch tests:Patch tests are generally thought to be more accurate than blood tests. They’re not commonly done but may be offered in a dermatology clinic, where a protein (e.g. beef) is mixed with petroleum jelly and taped on the skin for about two days, then tested a day later. If there’s irritation (redness, hives), it’s considered a positive test; if not, it’s negative.

 

Dog Food Allergy Treatment

Dog food allergy treatment boils down to one underlying principle: identify foods your dog is allergic to and avoid feeding him those. “That’s why the elimination diet and trial period is so essential,as it’s the only way to identify which foods, and food proteins, a dog can tolerate and which he can’t.” Now, if it’s a food intolerance rather than an allergy (which is far more likely), a food trial is still helpful, but a simple change of diet can be just as effective. A diet with a different composition from the one currently being fed is often enough to improve symptoms.

Unless formulated well, with the advice of a board certified or residency-trained veterinary nutritionist, many homemade diets are deficient in certain critical nutrients.

Aside from that, there are a few other tactics that come up in dealing with food allergies and intolerances. Here’s a brief overview, plus considerations, pros, and cons for each.

Antihistamines and Other Medications

Antihistamines like Benadryl can minimize itching, and they’re relatively safe and vet-approved for use at home. Topical anti-itch shampoos and ointments may help too—just be sure to get your vet’s OK before giving your dog any over-the-counter medication or remedy. Antibiotics and antifungals like cephalexin and ketoconazole, for example, may help in the short term to treat secondary infections that occur when the skin is inflamed, but symptoms usually recur after stopping.As for anti-inflammatory medications like steroids? “They typically don’t do anything to help many food allergy symptoms,” he says.

Homemade Dog Food Diets

Homemade diets are sometimes used for elimination diet food trials, and for dogs with food intolerances or allergies. It’s easy to see why they’re effective—the owner has total control over the ingredients. But there’s an issue with homemade dog food diets. Unless formulated well, with the advice of a veterinary nutritionist, many are deficient in certain critical nutrients,and those deficiencies could cause issues in the long run.” The preparation is labor-intensive for the owner, too.

Vegan Dog Food Diets

Likewise, vegan diets are used by some owners and veterinarians during and after food trials, but there’s no evidence they’re more favorable than a carefully selected diet with a single protein. (In fact, vegan diets often include a lot of different vegetable proteins.) But if a dog is allergic to multiple meats, a vegan diet is certainly one way to avoid them. Like homemade diets, vegan diets must be carefully formulated. “Some store-bought vegan diets were found to be deficient in critical nutrients, and they’re really only mentioned by vets because they’re becoming more and more popular among owners.It’s definitely not our top choice for treating food allergies.

Preventing Food Allergies

Is there anything we, as owners, can do to avoid food allergies from developing? This is one of the toughest questions in dog nutrition today. While we still don’t really know how to prevent allergies entirely, there are things you can do that may help your dog fight off numerous allergies.

Promote a healthy mucosal barrier.

This can be done by ensuring that our dogs, and especially puppies, have adequate nutrition and health care.

Watch out for gastroenteritis.

There have been some theories that early gastroenteritis or severe gastroenteritis, especially in puppies or young dogs, can result in an adult dog that is more likely to develop food allergies. Preventing gastroenteritis, in theory, is easy— just don’t let your dog eat anything but dog food and treats. In actuality, this is much harder to deal with. Dogs eat a variety of things, some that are not harmful—grass, dirt, bark, wild berries (i.e., raspberries, strawberries), sometimes a little cow or horse dung—and some that are not good for them (rotten garbage or dead animals). It can be very hard to police what goes in your dog’s mouth.

If you suspect that your dog has gotten into garbage or eaten something that may cause tummy upset, it may be best to feed your dog a low-protein diet (boiled white rice or potato) until the suspected tummy upset passes or you consult your vet. In general, if diarrhea lasts more than 72 hours without signs of getting better or if the diarrhea seems especially severe or malodorous, you should consult your vet. In these cases, do not attempt to treat the dog yourself with over-the-counter medications because diarrhea is the body getting rid of bad things in the gut. To give something that stops the diarrhea can result in keeping the bad things in the gut and causing a serious illness.

Promote effective protein digestion.

In general, your dog should have no problem digesting protein. If you are feeding a homemade cooked or raw diet, grinding or blending your protein source in a food processor can be helpful in improving protein digestion. In kibble-fed dogs, the protein is already ground before it is kibbled so there is no need to grind it.

Choose a dog food with exclusive protein sources.

A food that only has one or two protein sources can be helpful in giving you more choices later on should your dog develop an allergy. For example, if you use a food with five protein sources (i.e., turkey, chicken, duck, salmon, and tuna) and your dog develops an allergy to it, you now have to find a food that doesn’t contain any of these protein sources. This can be challenging. Conversely, if you feed a diet with chicken as its sole protein source and your dog develops an allergy to it, you can easily find a diet that doesn’t contain chicken.

Preventing food allergies may be impossible in dogs that are prone to developing food allergies. Some breeds are becoming noted for food allergies (see sidebar p.82). As a result, it is possible that a propensity for developing food allergies may be genetic, in which case, we should avoid breeding dogs that have food allergies.

Don’t Give Up

Dealing with a dog with food allergies can be challenging and disheartening. Proper diagnosis of food allergies can make it easier and understanding why food allergies start can help us prevent future allergies from starting.

 FAQ ON DOG FOOD ALLERY

Q: How common are food allergies in dogs?

A: Ten percent of all allergy cases in dogs are food allergies. Dogs also can suffer from food intolerance, which is different from a food allergy.

Q: What are the common signs of a food allergy?

A: Anything from chronic ear inflammation, gastrointestinal problems, and chronic diarrhea to chronic gas, licking their feet, or an itchy rear end.

Q: What are the most common things that could trigger a food allergy in my dog?

A: It’s a genetic problem, and when it’s triggered, it’s by exposure to whatever they’re allergic to. The most common allergens are beef, dairy, wheat, egg, chicken, lamb, soy, pork, rabbit, and fish. And, most dogs are usually allergic to more than one thing.

Q: What causes these allergies?

A: It’s a multi-factorial thing, but certainly you have to have a genetic predisposition to develop allergies. The environment can affect it, too.

There’s a lot of research going on right now to determine what, in early puppyhood or early kittenhood, makes the immune system more likely to express that trait. There’s an immune education process happening in the first few weeks of life. Young animals treated with antibiotics could potentially be predisposed to problems later in life because antibiotics change the environment inside the gut, which is the largest immune organ in the body. That could be a predisposing cause, but then the trigger would be being exposed to the allergen.

Q: Are some breeds more prone to food allergies?

A: There are some, but I think it depends on whom you talk to. It also can vary by country or part of the country. It may be as simple as what breeders, with their line-bred family of animals, are in your area. So if you have a very prominent breeder who is breeding a line known for their allergies, you’re going to think that breed commonly has food allergies. In my experience, retrievers, German shepherds. Dachshunds, cocker spaniels, and rex cats are the most commonly affected breeds.

Q: How do I determine if my dog has food allergies, or something else is causing the problem?

A: There’s only one way to diagnose food allergies accurately, and that is an elimination diet and challenge. So what we do is take the dog off all the foods it’s eating and we put him on a food that they have never had before. With all the exotic diets out there now, this can be pretty difficult. Once the dog has improved, we start reintroducing the old foods that we think caused the problems in the first place. If they have a reaction, which usually takes a few days to a few weeks, then we know they have a food allergy.

There’s specific testing to rule out other problems as well. For instance, you might take a sample of discharge from the ears to see if there’s a problem there, or do skin testing for environmental allergies. Blood testing is not an accurate test for any allergy.

Q: Will changing my dog’s diet trigger a food allergy?

A: If the dog has been sensitized to something in that diet it could. There’s no way of knowing if your dog has been sensitized to an ingredient, though.

Q: Can my dog suddenly develop a food allergy to something that they have eaten for years with no problems? Will this keep happening?

A: That’s common in food-allergic dogs. They have to be sensitized; they have to have been exposed for some period of time. So, in general, they’re not going to react really dramatically the first time they eat it but a dog that has eaten a food for years could suddenly become allergic to that food.

If an elimination diet improves the pet’s clinical signs and the owner is able to find two to three diets the dog can tolerate, I recommend rotating through them every two to three months. The whole point is to keep them stable for a period of months to years so you can eventually do their challenge testing to identify what the dog is really allergic to. If you’re really lucky, then you can go back to a more normal diet and not these expensive, exotic diets.

And if they’re young enough, food allergies sometimes do resolve themselves.

Q: How do I treat a dog with food allergies?

A: You can try to cover up the signs, but if you’ve got a disease that’s caused by what you put in your mouth every day, the best treatment is to stop putting that in your mouth every day. I use herbs all the time, and I do think they can help, but not as much as avoiding what’s causing the problem.

Q: Should I cook for my dog, rather than buy them food? What about a raw diet, will that help?

A: The upside of a cooked diet is you know exactly what’s going in it and you can control that. The disadvantage is it’s more trouble and, unfortunately, most people won’t do it right. They will leave off supplements, they won’t follow instructions, and they’ll end up giving their dog or cat an unbalanced diet.

There’s nothing magical about raw diets. Some dogs do very well on them and some dogs do not do very well on them. The protein structure might be different from that in a cooked or processed diet and that does make a difference for some dogs. But it’s not common enough that we need to tell everybody they should try a raw diet.

Q: Is there anything I can do to keep my puppy from developing food allergies?

A: I don’t think anyone is going to tell you that you can prevent food allergies if your puppy is predisposed. My opinion is that if you provide a diet that has some variety in it, so they’re getting a natural rotation, you’re maintaining gut health by doing that.

I do recommend for young puppies and kittens that people put them on probiotics. I’m very concerned about the use of antibiotics in growing animals. I think it messes up their gut balance and I think it may make them more likely to become allergic over time. So for puppies, I try to avoid antibiotics and use probiotics up to six months to one year of age and give them a diet that’s fairly high in variety.

DR AMIT BHARDAWJ,CANINE SPECIALIST,PUNE

https://www.pashudhanpraharee.com/common-causes-of-skin-problems-in-dogs/

https://veterinarypartner.vin.com/default.aspx?pid=19239&id=4951526

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