An allergy occurs when the immune system responds violently to a perceived threat, in this case, carrots. Carrots are not a common canine allergen, but they are used for sweetness in some foods and treats, and allergies can develop to any substance the dog is exposed to. Individuals who develop food allergies, such as allergies to carrots, will experience inflamed and itchy skin and may also develop chronic conditions such as indigestion, ear infections, and wheezing. Anaphylactic shock may also occur with food allergies, although it is rare with canines. Dogs who have confirmed allergies to other types of foods are more likely to develop allergies to new food sources, such as carrots.

An allergy to carrots is an over-reaction of your dog's immune system to an unwelcome protein that is present in the carrots themselves. As with any food related allergy, a diet containing carrots can be problematic if your pet has a sensitivity to them.

The symptoms of an allergy to carrots could include: 

Anaphylactic shock due to food allergy is not a common occurrence for dogs, but it does happen. Anaphylactic shock is an emergency, and your pet should be rushed for treatment to the nearest veterinary hospital if signs develop. These symptoms could include:

If your canine companion is not allergic to carrots, there are many great reasons to add carrot into their diets. Raw carrots are low in fat, and their texture is beneficial for cleaning the teeth. They are not particularly digestible for dogs due to the cellulose present in plant cells and most of the significant nutrients, like Vitamin A and Beta-Carotene, go right through their system unless the carrots are cooked prior to ingestion. Once the carrot is cooked, weakening the cell structure, the gastrointestinal system of the dog can utilize the vitamins, minerals, and fiber that are locked inside. Although carrots are generally a safe addition to your dog’s diet, moderation is necessary. If overly large quantities of Vitamin A build up in the body over time, it can cause distressing symptoms, including visual disorders, bone pain, and liver damage. Dogs with allergies to pears, apples, celery, cherries, tree nuts, or birch pollen may be more likely to develop allergies to carrots.

Allergies to carrots are due to an unwarranted defensive response to a protein in the carrot that your dog’s immune system views as an invader. Around 60-70% of the immune system cells of the mammalian body are estimated to reside within the digestive system mostly in the form of white blood cells known as enterocytes. The purpose of the digestive system is to break down the food we eat into their smallest parts, called amino acids, which are then absorbed by the enterocytes. When the proteins from the carrot are not thoroughly broken down during the digestive process, the enterocytes view them as intruders instead of  than nutrients and attack them. The response of the white blood cells to the proteins in the carrot will, over time, become more aggressive causing the symptoms to become more intense.

An allergic reaction produces symptoms that will prompt your veterinarian to collect skin scrapings.The samples from the affected areas will be used in a process called cutaneous cytology, which is the microscopic evaluation of the collected skin cells to search for signs of mites, yeast infections, or disease. A food allergy is likely to be suspected if no other underlying causes are brought to light. 

An elimination diet is usually employed to confirm the diagnosis of an allergy. An elimination diet is completed by replacing the diet your dog is currently eating with either a diet of limited-ingredient or hypoallergenic commercial dog food or a temporary diet of bland human food for several weeks. It is essential that your dog does not ingest anything other than the replacement food during the elimination trial. A single treat with an allergen can derail the entire process by causing the allergy to resurface. Each of the ingredients in the dog’s current diet should be avoided when choosing a replacement food as the symptoms may be triggered by multiple allergens. It is also possible that your pet is allergic to the entire food family, so switching from a chicken diet to a red meat source such as bison or venison is a more valuable diagnostic technique than turning to another avian species like duck or goose. If your pet has a predisposition for food allergies multiple allergens may be involved. A properly executed elimination trial will cause the signs of allergy to cease until the allergen is reintroduced.

Elimination diets usually take several weeks to confirm an allergy exists, and longer to reveal that the allergy is to carrots or in the carrot family. During this time your pet may continue to experience symptoms until the problematic food antigens have been expelled from their system. Many veterinarians will choose to complete the diagnosis through the elimination diet before applying any medications such as corticosteroids or antihistamines to relieve itching and swelling. Although these preparations can be highly efficient at easing dermal symptoms they are also capable of obscuring the origin of the allergic reaction by masking the signs and symptoms of the allergy. Secondary skin infections are common due to the damage to the epidermis and antibiotics may be prescribed to eradicate these conditions. Once the source of the allergy has been identified as carrot, you will need to avoid feeding that ingredient to your dog in the future.

Food allergies are not a curable disorder, but the allergy related symptoms are easily dispersed by cutting the allergen from your dog’s diet. An allergy to birch tree pollen is an indicator that allergies may later expand to include plants with a similar protein structure such as pears, apples, celery, cherries, tree nuts, and carrots. If your canine has had an allergic response to one kind of food, they are more likely to acquire additional food-related allergies, particularly foods similar to the one they are allergic to. The approach to combat this situation varies within the veterinary profession, with some doctors maintaining that a steady rotation of three of four novel protein foods is optimal and other advocating that your pet remains on a single source of food as long as new allergies do not develop.