Canine Food Allergy Lesions
Graphic by MarVistaVet
Graphic by Mar VistaVet
Your Pet's Itchy Skin
Itchy skin in dogs and cats is often more than just a minor annoyance. Red, oozing bald patches; rashes; and large expanses of hair loss are unfortunate markers of very real discomfort. The cause should be determined.
Food allergy is one of the itchiest conditions for cats and dogs. Animals eat a variety of processed food proteins, flavorings, and colorings thatare 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. In dogs, signs include facial itching, foot or limb chewing, itchy anal area, and recurrent ear infections.
Many people erroneously assume itching due to food allergy requires a recent diet change of some sort. In fact, the opposite is true.
Food allergies require time to develop; most animals have been eating the offending food for years with no trouble.
What Kind of Allergy?
Diagnosing and treating allergic skin disease and its secondary infections make up a large proportion of cases seen in small animal practice. Pets can be allergic to insect bites (fleas are not inherently itchy unless the pet is allergic to flea bites), airborne proteins (such as molds, pollens, and dust mite parts) or foods. Pets can and often do have multiple allergies adding together to make them itchy. The skin infections that come from scratching perpetuate the itching. To solve the problem, the infection must be cleared up and the offending allergen(s) removed from the pet's world.
There is controversy about how common food allergy is in dogs and cats. Some experts feel it is relatively rare while others feel is much more common than we realize. It is hard to tell because there is no simple test for food allergy and the skin lesion distribution is difficult to distinguish from that of airborne allergy, which is frequently concurrent in the same patient.
So what are our clues that a pet has a food allergy? There are several hints:
- The itching is not seasonal (this is obviously hard to tell in areas that do not freeze during winter).
- Itching started when the pet was less than 6 months of age or greater than 5-6 years of age.
- No response to treatment for sarcoptic mange(a condition with a similar itchy skin pattern).
- Corticosteroids have not been helpful in managing the itching. Corticosteroids may or may not work on food allergy itching but they almost always work for other allergies.
- There are accompanying intestinal signs like vomiting or diarrhea. These are seen in 30 percent of food allergic pets.
- The lesion distribution is compatible with food allergy, especially if an itchy anal area and/or recurrent ear infections are involved.
Any of the above findings or observations warrant pursuit of food allergy.
Please note that several of the above criteria relate to what you observe at home. Trouble results when the veterinarian must speak to different family members about the pet and there is disagreement in their observations. It is best to have one person, preferably the one who has the most contact with the pet, be the spokesperson and make the relevant judgments.
The Flea Factor
Ctenocephalides Felis. Photo by Dr. Cathy Wilkie.
Some animals have many allergies. It would not be particularly unusual for a pet to have a food allergy and another type of allergy at the same time.
Ensure immaculate flea control for any itchy pet!
For more information on the current proliferation of flea products, seea product comparison chart so you can pick the best product for your situation. Remember, all dogs and cats in the home must be treated.
How to Deal with the Food Allergy Suspect: The Hypoallergenic Diet Trial
What about Blood/Hair/Saliva Tests for Food Allergy?
The short answer is to not waste money on these tests. Blood tests for allergy can detect antibodies against certain food proteins, but this does not necessarily mean the pet has an allergy. It may mean nothing more than the pet has eaten that type of protein before. Furthermore, the pet's body may alter a food protein during digestion and it is the altered protein that generates the allergy. There is no predicting how a protein could be altered and thus no test can be devised for altered proteins. Laboratory tests are simply not valid for determining if a pet has an allergy against a certain type of food.
The Basic Principle
To determine whether or not a food allergy or intolerance is causing the skin problem, a hypoallergenic diet is fed for a set period of time. If the pet recovers, the original diet is fed for up to two weeks to see if itching resumes. If we see recovery with the test diet and itch with the original diet, then food allergy is diagnosed and the pet is returned to either the test diet or another appropriate commercial food indefinitely.
There is no other way to determine if a pet has a food allergy. Blood tests are not useful.
Before reviewing diet strategies for this process, here are some additional concerns:
- The diet must be strict (meaning the pet should not have any other protein sources besides the test protein). This includes rawhides and chew toys, flavored chewable medications (these will need to be changed for unflavored tablets) and vitamins, and treats.
- All family members must be on board with the trial. No one should be giving the pet other foods or treats when no one else is looking.
- It is probably best for all animals in the house to be fed the test protein so as not to have food-sharing issues.
- Itching must be managed during the trial in a way that the results of the trial are not foiled.
- Diet trials often span a season change period. If a dog has a pollen allergy and winter comes during the period of the diet trial, it may appear that the diet worked when, in fact, the seasons simply changed. This is why diet challenge is important at the end, even if the pet is doing well.
What is a Good Hypoallergenic Diet?
There are two approaches to test diets: novel protein and hydrolyzed protein. Traditionally, a novel protein is used. This is a diet with a single protein source that the patient has never eaten before. It typically takes years to become allergic to a food protein so the patient should not be allergic to something new.
Fortunately, many pet food companies have discerned the need for diets using unusual proteinand carbohydrate sources with a minimum of additives. Foods can be obtained based on venison and potato, fish and potato, egg and rice, duck and pea, and even kangaroo. Diets used for allergy trials must contain basically one protein and one carbohydrate source and neither can be something the pet has had before. Recently several diets that include duck, venison, and so on have been released to the general market. Be aware of foods that contain these ingredients because these ingredients will not be useable for future diet trials if they were ever used in the pet's regular food.
It is important that no unnecessary medications be given during the diet trial. No edible chew toys (such as rawhides or bones) should be given. Treats must be based on the same food sources as the test diet. (Beware of rice cakes, though, as wheat is commonly used as a filler.) Chewable heartworm preventives should be replaced with tablets.
Over the Counter Food? Therapeutic Diet? Home Cooked?
Recently several pet food companies have released single protein diets for over-the-counter sales. These tend to cost less than the therapeutic diets available from your veterinarian's office directly. While these diets are attractive, they are probably not a good choice for an actual diet trial. Immunological tests on these foods found that many of them contain additional proteins (probable contaminants from prior batches in the pet food factory). These impurities could defeat a diet trial which is hard enough to perform without such issues. The therapeutic diets did not have these contaminants.
Home cooking is a fine alternative to commercially prepared foods for the diet trial. The problem is that the test diets will most likely not be balanced but for the 2 months or so of testing, this should not be a problem. Home cooking is a bit of an inconvenience but for the right person, it is a good choice. Ideally, a nutritionist should be involved in designing the diet. Recipes for appropriate diets can be purchased through BalanceIt, Petdiets.comor by any nutritionist listed at the American College of Veterinary Nutrition web site.
The Hydrolyzed Protein Method
Recently a new approach has been introduced using therapeutic diets made from hydrolyzed proteins. This means that a conventional protein source is used but the protein is broken down into molecules too small to excite the immune system. Some hydrolyzed diets are on the market; discuss with your veterinarian which is best for your pet.
How Long to Feed the Trial Diet
Studies have shown that 80 percent of dogs will have shown a response by 4 to 6 weeks on the diet but by extending the diet to 8 weeks, 90 percent will respond. The Labrador retriever and cocker spaniel appear to require longer trials. Most veterinary dermatologists recommend 8 to 12 weeks, which is a long time to be strict on the diet but that is the only way to detect food allergic dogs.
Photo by VIN
Most commercial diets used in food allergy trials have a 100 percent guarantee.This means that if your pet doesn’t like the food, the food can be returned for a complete refund, even if the bag is opened. This is especially helpful for feline patients, as cats are famous for being choosy about what they are willing to eat.
What to do if the Diet is Successful?
To confirm food allergy, return to the original food; itching generally resumes within 14 days if food allergy was truly the reason for the itchy skin. Many people do not want to take a chance of returning to itching if the patient is doing well; it is not unreasonable to simply stay with the test diet if the pet remains free of symptoms. Often it is difficult to remember 10 to 12 weeks later how itchy the dog used to be before the diet trial. The diet challenge helps make it more obvious whether the diet trial has worked or not.
It is possible to more specifically determine the identity of the offending foods after the pet is well. To do this, a pure protein source (such as cooked chicken, tofu, wheat flour, or any other single food) is added to the test diet with each feeding. If the pet begins to itch within2 weeks, then that protein source represents one of the pet's allergens. Return to the test diet until the itching stops and try another pure protein source. If no itching results after two weeks of feeding a test protein, the pet is not allergic to this protein.
What to do if the Diet is Unsuccessful?
Assuming secondary skin infections have been controlled, an unsuccessful food trial is strongly suggestive that an inhalant allergy is the primary problem but there are some other considerations that should at least be mentioned:
- Are you certain that the dog received no other food or substances orally during the trial?
- Was sarcoptic mange ruled out?
- Your pet may require a longer diet trial. Are you certain regarding the factor which pointed toward the food allergy?
If your pet has not been biopsied, now may be a good time. If an inhalant allergy has risen to the top of the list, symptomatic relief either via medication, baths with specific shampoos, or allergy shots will likely be necessary. Chronic itchiness can be extremely uncomfortable and prompt relief is our goal as well as yours.
Information on itch relief.
Information on inhalant allergy.
Information on sarcoptic mange.
What are the signs of a food allergy in dogs? ›
In the dog, the signs of a food allergy are usually itchy skin, paws, or ears or digestive disturbances such as vomiting or diarrhea. Other more subtle changes can also occur, including hyperactivity, weight loss, lack of energy, and even aggression.What is the most common food allergy in dogs? ›
Some of the most common allergens in dog food include beef, dairy, wheat, eggs, chicken, lamb, and soy. If you suspect your dog has a food allergy or intolerance, it's important to consult with your veterinarian.What are the symptoms of a dog being allergic to a cat? ›
Some of these symptoms include “lots of scratching and licking, leading to skin changes, such as redness, excoriations (repetitive scratching) and the development of pustules and/or crusts.” Some dogs may also exhibit respiratory signs, such as coughing, sneezing or watery eyes and nose, says Dr.Is cat allergy different to dog allergy? ›
Proteins within dander
' cat dander is slightly stronger than dog dander. That's because of a protein called Fel de 1 in cat dander which is small, sticky and can stay airborne for hours. The fact that cat dander is stronger also means that more people suffer from allergies to cats.
It can take several weeks to months for clinical signs to resolve once the allergenic agent is removed from the animal's diet. Up to 30% of food-allergic pets may have other allergies, such as a flea allergy dermatitis or atopy (environmental allergies).Does Benadryl help dogs with food allergies? ›
What Does Benadryl Treat in Dogs? Benadryl is a great medication for use in dogs with mild-to-moderate allergies. Seasonal allergies, food allergies, environmental allergies, and allergic reactions to snake and insect bites all respond to Benadryl in most cases.What is best food for dog with allergies? ›
- Canine Hydrolyzed Protein Small Dog Dry Dog Food.
- Hill's Prescription Diet® d/d Canine Potato & Venison Formula.
- Purina Pro Plan FOCUS Adult Sensitive Skin & Stomach Salmon & Rice Formula.
- Hill's Prescription Diet® Dog i/d® Sensitive Dry.
Symptoms of Chicken Allergy in Dogs
Symptoms could include red or itchy skin (especially on the paws, abdomen, groin, face, and ears), rashes, fur loss, or hives. Skin and ear infections commonly occur. And wounds or “hot spots” may develop due to trauma from a dog repeatedly licking or chewing their skin.
- Nom Nom Fresh (Limited Ingredient Food) ...
- Wellness Simple (Limited Ingredient Food) ...
- Royal Canin Veterinary Diets Hydrolyzed Protein (Hypoallergenic Food) ...
- Merrick Limited Ingredient Diet (Limited Ingredient Food) ...
- Purina Pro Plan Veterinary Diets (Hypoallergic Food)
Antihistamines reduce the production of an immune system chemical that is active in an allergic reaction, and they help relieve itching, sneezing and runny nose. Prescription antihistamines taken as a nasal spray include azelastine (Astelin, Astepro) and olopatadine (Patanase).
How do you get rid of cat and dog allergies? ›
- Avoid being around dogs and cats; if you have a pet at home, take specific steps to limit exposure.
- Nasal sprays, antihistamines and bronchodilators can help relieve symptoms.
- Consider allergy shots ( immunotherapy ).
Treatment for Dogs That Are Allergic to Cats
“Once your dog has been tested, he can be treated with individual immunotherapy,” says Trimble. “Immunotherapy involves daily exposure to the specific allergens the dog is sensitive to, either by daily injection or by a daily oral spray/oral drops.
Apple cider vinegar, coconut oil, or aloe vera can be put on the skin to calm any itching. A relaxing oatmeal bath can relieve itching, burning, and dry skin.What are the most common pet allergies? ›
- Flea allergy dermatitis.
- Food allergies.
- Environmental allergens.
Your doctor will diagnose a pet or animal allergy based on your medical history, symptoms, a physical exam, and allergy test results. Allergy testing is the best way find out if you allergic to a specific animal type. Your doctor can use either a blood test or skin test to help get a diagnosis.Can dogs suddenly become allergic to their food? ›
It's important to remember that food allergies can develop at any time. A food your dog has consumed for years with no troubles may suddenly cause an allergic reaction, or symptoms may develop soon after you change your dog's diet.Can dry dog food cause allergies? ›
Dry dog food allergies in dogs are a result of the hypersensitive immune system of the dog to a particular ingredient within the dry dog food. Dry dog food allergies may not occur immediately; they usually develop over time after being fed the same ingredients on a regular basis. Protect yourself and your pet.Do food allergies go away in dogs? ›
You cannot cure your dog's food allergies, but you can successfully manage them with specialized treatments and a hypoallergenic diet. Once the allergen is identified, the best treatment is total avoidance.How fast does Benadryl work for food allergies? ›
Diphenhydramine has been commonly used as the antihistamine of choice for acute food allergic reactions given its prompt onset of action (15–60 minutes)1 and ready availability, though epinephrine is still the first-line therapy for anaphylaxis.How much Benadryl should I give my dog for allergies? ›
According to the Merck Veterinary Manual, the standard dose for Benadryl is 2-4 milligrams per kilogram of body weight, or 0.9-1.8 milligrams (mg) of Benadryl per pound. Therefore, a simple and practical dose is 1 mg of Benadryl per pound of your dog's weight, given 2-3 times a day.
What foods to avoid for dogs with skin allergies? ›
Along with some other types of fish, salmon is also a good protein source. In fact, salmon is a common ingredient in high-quality dog foods. If your dog is allergic to more common sources of protein like chicken, salmon may be a good alternative.What dog breeds are allergic to chicken? ›
While chicken allergy can affect any dog breed, some are more susceptible, including Labradors, Golden Retrievers, Cocker Spaniels, and German Shepherds.What should I feed my dog if he's allergic to chicken? ›
If your dog is allergic to chicken, there are a variety of protein sources and dog food brands available that are chicken-free and may be a good option for your dog. Some common protein sources that may be used in place of chicken include beef, lamb, fish (e.g. salmon, whitefish), duck, turkey, and venison.Does Zyrtec help with cat and dog allergies? ›
Pet allergy relief
When you can't live without your pet, a medicine for dog and cat allergies can help control your pet allergy symptoms. ZYRTEC® starts working at hour 1 and stays strong day after day, so you can reduce your cat and dog allergy symptoms.
When strict flea control is not possible, or in cases of severe itching, your veterinarian may prescribe antihistamines or corticosteroids (steroids) to block the acute allergic reaction and give immediate relief. If a secondary bacterial infection is present, an appropriate antibiotic will be prescribed.Is Claritin or Zyrtec better for pet allergies? ›
You may be wondering whether Claritin or Zyrtec is the best pet allergy medicine—but which antihistamine works best for you depends on the severity of your symptoms. For example, a person with a mild allergy to cats or dogs may do well with Claritin. Another person with more severe allergies may do better with Zyrtec.Does Benadryl help with cat allergies? ›
How to treat cat allergies. Avoiding the allergen is best, but when that's not possible, the following treatments may help: antihistamines, such as diphenhydramine (Benadryl), loratadine (Claritin) or cetirizine (Zyrtec) corticosteroid nasal sprays such as fluticasone (Flonase) or mometasone (Nasonex)What does a vet do for a cat with allergies? ›
Corticosteroid therapy (especially for asthmatic cats) Allergen-specific immunotherapy (a.k.a. allergy shots) for severe cases. Prescription dietary supplements. Prescription or vet-approved lotions, ointments, ear drops or eye drops.How long do cat and dog allergies last? ›
How long do pet allergy symptoms last? Pet allergy symptoms will last until the animal is permanently removed from the home. However, many symptoms can last for months afterward as pet dander and fur can stay in a home for months and even years later. Often, carpets hold animal dander and fur much longer.
Is Benadryl or Zyrtec better for dogs? ›
Other safe antihistamines for dogs include Claritin (loratadine) and Zyrtec (cetirizine). They produce less sedation than Benadryl does but could still make your dog drowsy. Warning: Make sure your OTC allergy medicine only contains antihistamine.What can I feed my dog for itchy skin? ›
- Fish Oil. The Omega-3 fats found in fish oil help reduce inflammation, which can lessen the intensity of many allergies. ...
- Coconut Oil. Coconut oil can improve many skin conditions including itchiness and dryness. ...
- Digestive Enzymes. ...
- Quercetin. ...
Apple Cider Vinegar For Dog Skin Allergies
ACV can help relieve itchy skin and rashes caused by yeast and poison ivy. The best way to apply it is by making a 50/50 solution of apple cider vinegar and water in a spray bottle. Apply it directly onto itchy spots.
Most often, pet allergy is triggered by exposure to the dead flakes of skin (dander) a pet sheds. Any animal with fur can be a source of pet allergy, but pet allergies are most commonly associated with cats and dogs.What foods are toxic to dogs? ›
- Onions, garlic and chives. The onion family, whether dry, raw or cooked, is particularly toxic to dogs and can cause gastrointestinal irritation and red blood cell damage. ...
- Chocolate. ...
- Macadamia nuts. ...
- Corn on the cob. ...
- Avocado. ...
- Artificial sweetener (Xylitol) ...
- Alcohol. ...
- Cooked bones.
- Wash up. Ideally, you'd wash your pets once or twice a week. ...
- Declare the bedroom a pet-free zone. ...
- Brush or comb regularly. ...
- Clean and pick up. ...
- Use an allergen-capturing air filter. ...
- Consider the whole environment. ...
- Get medical help. ...
While many tests – using blood, saliva, and even hair – that can be performed a veterinarian or purchased by a pet owner online (and even sometimes shockingly, through a Groupon!) advertise that they can diagnose food allergies or “sensitivities”, there is no proof that they work.Can the vet tell if my dog has allergies? ›
Seasonal/environmental allergy testing can be performed in dogs by either skin testing or blood testing. Skin testing is the most accurate type of allergy test, and it's generally performed by board-certified veterinary dermatologists.Do I need to take my dog to the vet for allergies? ›
Some causes and symptoms of dog allergies are mild and can wait until your pet can see a general vet, while others are seen as more harmful and require your pet to need emergency care. If you notice your dog is having these problems, it's better to get them to see by a vet as soon as possible.How do dogs act when they are allergic to something? ›
Common symptoms include scratching/itchy skin, licking (especially the paws), and face rubbing. Affected dogs may also experience red skin, loss of fur, and recurrent skin and/or ear infections. You may see red skin or fur loss on your dog's paws and lower legs, face, ears, armpits, and belly.
How do you treat food allergies in dogs? ›
Treatment of Food Allergies in Dogs
It can take several weeks for the elimination diet to reveal the allergen and during this time your pet may still be experiencing some symptoms. Corticosteroids may be recommended by your veterinarian to reduce swelling as well as antihistamines to calm the itching.
First and foremost, make an appointment to take your dog to your veterinarian if you suspect your dog has a food allergy. Food allergies symptoms can mimic other diseases, so it's vitally important that you have your dog checked out by a professional.Can a dog suddenly become allergic to his food? ›
It's important to remember that food allergies can develop at any time. A food your dog has consumed for years with no troubles may suddenly cause an allergic reaction, or symptoms may develop soon after you change your dog's diet.How do vets test for food allergies in dogs? ›
Skin testing — officially called intradermal skin testing — involves giving your dog small doses of several types of allergens directly into the skin, much like tuberculosis tests for humans. Skin tests are performed at a vet clinic since your dog will need to be sedated for this process.What medication can I give my dog for food allergies? ›
Antihistamines like Benadryl and Zyrtec
ANTI-histamines, such as diphenhydramine (Benadryl®), certirizine (Zyrtec®), and hydroxyzine, are commonly taken by humans to treat allergy symptoms and can be used for dogs as well. These medications work by preventing histamine from binding to cells and exerting its effects.
Unfortunately, allergies are quite common in dogs of all breeds and backgrounds. Most allergies appear after the pet is six months of age, with the majority of affected dogs over the age of one or two. This is because it takes time for the body to become “sensitized” to the substance the pet is allergic to.