March 5, 2026, 3:43 pm | Read time: 6 minutes

Allergy or Intolerance? An Overview of the Differences

Food Allergy (Immunological Reaction of the Immune System)
An allergy is an excessive, pathological immune response. In a food allergy, the body reacts to a foreign substance from outside and classifies it as dangerous. This immune response causes the associated allergic symptoms, which persist as long as this substance continues to be introduced into the body.

Food Intolerance (Metabolic or Digestive Problem)
Food intolerance does not trigger an immunological reaction in the body. It is usually an enzyme defect that causes symptoms because the metabolism and digestive organs cannot normally digest and process the substance. A typical example is lactose intolerance in dogs.

How to Recognize a Reaction Specifically to Food?

The symptoms of a food intolerance or allergy in dogs are often similar and therefore not always clearly attributable. However, the triggers for an allergy do not always have to be related to food. Dogs can also react to airborne allergens or contact allergens such as pollen, grasses, house dust mites, mold, cleaning agents, or flea saliva.

This should be clarified and ruled out, just like a parasite infestation, before considering food as the cause. If the following characteristics apply to the animal regardless of the season, it is likely a reaction to food.

The most common signs of a food allergy or intolerance are:

• Gastrointestinal issues such as diarrhea, bloating, cramps, or vomiting
• Itching, leading to increased licking or biting, often on paws, ears, the abdominal area, or the anus
• Skin irritations such as redness, inflammation, dandruff, or pustules
• Anal gland inflammation
• Dull-looking coat or hair loss
• Recurring or chronic ear infections
• Behavioral disorders

Possible Triggers

In a reaction to food, the dog’s body reacts to:

• Animal or plant proteins, such as a specific type of meat (often beef or chicken), other protein components (egg, fish), or histamine
• Carbohydrate-containing foods such as grains (gluten), soy, milk, etc.
• Chemical additives, such as artificial preservatives, colorings, or flavor enhancers

Since our household dogs are usually fed with food and treats composed of 3–4 different protein sources, the allergy potential is relatively high.

Measures for Food Intolerance or Allergy in Dogs

• Switching to hypoallergenic food: However, this food is usually made on an insect or plant basis and contains few other nutritionally important components. Unfortunately, it often does not ensure a species-appropriate, healthy, and balanced diet in the long term.
• Medications: There are specific medications for allergic symptoms. Since these often have undesirable side effects, this treatment is not a permanent solution.
• Accurate diagnosis of the allergy trigger.

Ways to Diagnose an Intolerance or Allergy

It is important to identify which protein is responsible for a food intolerance or allergy in the dog to replace it permanently. There are various methods for this.

• Blood test (serological allergy test) at the veterinarian or animal healer: Unfortunately, this test is not always fully conclusive and clear in dogs, and the costs are very high (up to 800 EUR).
• Skin, saliva test, or hair analysis: Unfortunately, not all relevant allergens can always be clearly identified, especially when it comes to food.
• Exclusion diet (elimination diet): In this very promising method, the dog is fed exclusively with one protein source, i.e., one protein and one carbohydrate source, for at least 6–8 weeks, with which the animal has never had contact before. Suitable options include varieties such as insects, horse, ostrich, goat, or kangaroo, combined with (sweet) potatoes, millet, amaranth, or oats.

During this time, other food, snacks, and treats or table scraps should be strictly avoided to prevent skewing the results. If symptoms improve while feeding the new protein, the allergy trigger is usually already found. If the first attempt fails, the exclusion diet can be repeated as often as necessary.

In the long term, a combination of a meat source and a carbohydrate source does not provide a balanced diet for a dog, so an exclusion diet is unsuitable for puppies.

It should gradually be supplemented with minerals, vitamins, trace elements, high-quality fatty acids, and fiber, or slowly transitioned back to suitable commercial food. During an exclusion diet, a veterinarian or animal healer should accompany and support the owner and the animal.

Special Food Types for Dogs with Food Allergies

• Monoprotein food, consisting of only a single protein source
• Hydrolyzed food, where the protein molecules are so cleanly and finely broken down that they do not trigger an immune reaction
• Home-cooked food or BARF feeding according to an individually created feeding plan from a veterinarian or nutritionist

More on the topic

Itching and Rashes How to Identify Food Allergies in Dogs and Cats

Diagnosis, Treatment Cats and Dogs Can Also Develop a Pollen Allergy — These Are the Symptoms

Are There Breeds That Are More Often Affected?

No, an intolerance or allergy can be present in any dog or develop over the course of its life. However, some breeds are more prone to it. These include the German Shepherd, Labrador Retriever, Dalmatian, Cocker Spaniel, Boxer, and West Highland White Terrier.

How Can I Prevent Food Intolerance or Allergy in Dogs?

• High-quality and healthy nutrition: good quality food, snacks, and treats with clearly declared ingredients, without unnecessary additives
• Cautious approach to changes and transitions in feeding and food: always proceed slowly and controlled, closely observing the organism’s reaction (ideally with expert support), possibly keeping a food diary
• Pay attention to gut health: maintaining and strengthening the gut flora through probiotic supplements or detoxification after medication, anesthesia, or deworming treatments