What are Food Allergies?
Canines who develop allergies to foods can experience uncomfortable itching of the skin as well as chronic conditions such as ear infections, gas, and wheezing. An allergy is the immune system of the body responding to a perceived threat, in this case, an ingredient in the diet of the dog. In order to reliably determine which allergen is affecting your pet, an elimination diet may be recommended. This can be time-consuming, but is necessary in order to deduce which ingredient is causing the reaction.
A food allergy is an over-reaction of your dog's immune system to an unwelcome protein that is present in a particular ingredient of their diet.
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Symptoms of Food Allergies in Dogs
Food allergies in canines can develop at any age, but the majority of dogs do not acquire food allergies until they are older than three years old. Skin reactions are often located around the face, groin, under the front legs, or between the toes.
- Bald patches
- Chronic ear infections
- Chronic gas
- Chronically inflamed feet
- Face rubbing
- Head shaking
- Obsessive licking
- Paw biting
- Poor puppy or adolescent growth
- Skin infections
- Skin rashes
Food allergy - An allergy to food is a response by the body’s immune system to defend itself against a threat. An allergic reaction doesn’t happen the first time an individual is exposed to the allergen but rather after repeated exposures. Any food can cause an allergic reaction, but some foods, such as beef, dairy, chicken, and eggs tend to cause allergies in canines more often than others.
Food intolerance - While a food allergy is the body’s immune system reacting to what it perceives as a threat, food intolerance has no immune involvement. An intolerance to a food type is more likely to cause a gastrointestinal response than allergies do. Additional symptoms, such as a change in the consistency or color of the stools and gurgling sounds from the digestive system are common with a food intolerance.
Causes of Food Allergies in Dogs
Allergies of all sorts are due to an abnormally strong defensive response to a protein that the immune system considers to be an invasive substance. It is estimated that around 60-70% of our immune system cells actually reside in the digestive system, and the same applies to our canines. The process of digestion is designed to break down our foods into their smallest parts, which are known as amino acids. These amino acids are then absorbed by white blood cells called enterocytes. When proteins are not properly broken down during digestion, these enterocytes see them as intruders and attack. Over time the response of these cells becomes more aggressive, and symptoms intensify.
Although any food can become an allergen, some foods are more likely to generate a reaction than others. Frequent offenders for canines can include:
- Dairy products
Diagnosis of Food Allergies in Dogs
The symptoms that your dog will be showing due to an allergic reaction will prompt your veterinarian to collect skin scrapings from any affected areas for cutaneous cytology. Cutaneous cytology is the microscopic evaluation of the skin cells to look for problems like mites, yeast infections, or signs of disease. When these are not found on the dermal cells, then a food allergy may be suspected. In order to confirm the allergy, an elimination diet is usually implemented. An elimination diet usually involves changing the dog's food to either a reduced ingredient commercial food or a diet of bland human food, such as a boiled protein and a simple carbohydrate like rice.
Novel ingredients are generally used for an elimination diet, meaning proteins and carbohydrates that are not common in the dog’s current diet. All of the ingredients in the current food should be avoided when determining the proper replacement food. In many cases it may be the entire food family that your pet is reacting to, so switching from a chicken diet to a mammalian source such as rabbit may have better results than switching to another avian species like duck. If the symptoms are caused by an allergy, a properly implemented elimination diet will cause them to cease. Once this has occurred additional ingredients will be slowly added into the diet until the allergen is identified. During this time, it is essential to ensure your dog does not ingest anything other than the food used for the elimination diet. A single treat with the allergen can cause the allergy to resurface. Sources to avoid include:
- Cow hooves
- Flavored medications (including heartworm preventives) or supplements
- Flavored plastic toys
- Flavored toothpastes
- Pigs Ears
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. Use of these treatments may make it harder to determine which ingredient in your dog’s diet is causing the reactions by masking allergic symptoms, so many veterinarians prefer to complete the elimination diet before applying these types of medications. Secondary skin infections are commonly seen with food allergies, and antibiotics may be prescribed to combat this problem.
Once the allergen has been identified, the initial course of action is avoidance of the ingredient. Other supplements, such as Omega-3 oils and probiotics, may be recommended as well after the elimination diet is completed to support the immune system. This will assist your canine’s body in handle any accidental exposure to allergens and to prevent the cultivation of new allergies.
Recovery of Food Allergies in Dogs
Allergies to foods are not curable, but symptoms usually cease if the allergen is removed from the animal’s diet. Any exposure to the allergen can cause a relapse, so care must be taken in the type of treats and flavorings you use for your dog. Unfortunately, if your canine has had an allergic response to one type of food they are more likely to develop an allergy to the ingredients in the replacement diet over time as well.The approach to combat this situation varies within the veterinary profession, with some doctors advocating that your pet remain on a single source of food, while others maintain that a steady rotation of three of four novel protein foods is optimal.
Food Allergies Questions and Advice from Veterinary Professionals
Myself and my dog moved from the US to the UK nearly 2 months ago and ever since we’ve been here she has been having health issues. Before she was shipped she was perfectly healthy and got her health certifications to fly internationally. The first thing I noticed was every time we went on walks she would chew on grass which I’ve never seen her do before. Then about two weeks ago she had bloody diarrhea in the middle of the night. I restricted food for one day and then put her on a boiled chicken, sweet potato, and rice diet for 2 days and her diarrhea improved. After that I put her back on her kibble but kept mixing it with rice/(cooked)sweet potato. I noticed that she had bumps all over and she was chewing obsessively and licking her paws and that her rib cage felt bonier even though she was eating extra calories. She has also been vomiting yellow bile on occasion. My instincts are telling me it may be an allergy to chicken because although she is on a premium dog food it has 3 different forms of chicken in the ingredients, and her treats have chicken too. The food she was on previously was salmon and sweet potato, and lamb and rice as a puppy so she’s never been exposed to it until now. Her vet didn’t seem to be concerned with the bloody diarrhea since it had stopped (which may only be from adding rice to her diet) and was more concerned with what was causing the skin issues so she gave her a topical parasite treatment (advantage) and a steroid injection to hopefully calm the chewing. She stopped chewing for one day but seems to be chewing more than ever and now has sores and thinning hair. She suggested waiting to see if she improved, and then continue with trial and error, but I’m wondering if I can just switch her back to a sweet potato and salmon food and cut out all chicken now in case it could be something as simple as a food allergy. I know she is exposed to a lot of different things environmentally that she could be reacting to but thought of feeding her something everyday that could be causing this reaction is very upsetting.
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