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Itching and Rashes

How to Identify Food Allergies in Dogs and Cats

Dog Scratches Itself on the Sofa
If the dog keeps scratching, a food allergy might be the cause. Photo: Getty Images
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November 14, 2025, 1:31 pm | Read time: 3 minutes

Itching, skin rashes, or inflamed paws—when such symptoms repeatedly appear in dogs or cats, alarm bells ring for pet lovers. The cause might be closer than many think: The food itself can be the trigger. Animals, too, can have an allergy to certain food components. What owners should know—and how an elimination diet can help identify the culprit.

When the Pet’s Immune System Overreacts

The answer might lie in the food bowl. Dogs and cats can develop food allergies over time, according to the German animal welfare organization Vier Pfoten (Four Paws). When this happens, the animal’s immune system mistakenly identifies harmless protein components in the food as a major threat. As a result, messenger substances are released, causing unpleasant symptoms. 

Common triggers for food allergies, according to Four Paws, include: 

  • For dogs: beef and lamb, poultry, grains, dairy products
  • For cats: beef, chicken, fish

These Are Signs of a Food Allergy

In addition to itching, rashes, recurring inflammations, and hair loss, these symptoms are typical of food allergies: 

  • Dogs may experience vomiting, diarrhea, and flatulence.
  • Cats often exhibit excessive grooming, as well as increased scratching and licking, sometimes leading to skin wounds.

If you notice that your four-legged friend is suffering from such symptoms, it should be clarified with a veterinarian—also to rule out other diseases. 

More on the topic

Clarifying Suspicions with the Elimination Diet

What exactly is my pet reacting to? The so-called elimination diet comes into play in the search for an answer. It should be conducted in consultation with a veterinarian. 

Initially, the pet’s diet includes only a single animal protein source. Horse meat, for example, is well-suited as it is considered hypoallergenic. 

Grains and dairy products are initially off-limits in an elimination diet—after all, they can also be potential allergy triggers. “You might choose food that also contains carbohydrate additives like sweet potato or parsnip,” advises veterinarian Sabrina Karl from Four Paws. 

Dogs or cats should be fed the elimination diet for at least six to eight weeks. During this time, allergy symptoms should subside. The most important rule to ensure this plan works: no exceptions. “Snacking on other treats is absolutely forbidden during this time,” says Karl. 

Gradually Testing

Once the period is over, pet owners can introduce a second protein source and feed it for a few weeks. Do the symptoms return? If so, you’re on the trail of the trigger. If the pet remains well, owners can gradually add more protein sources—until symptoms reappear. 

Found the trigger? Very good. It should be consistently removed from the pet’s diet in the future. Four Paws recommends seeking advice from a veterinary practice or specialists in animal nutrition on what to focus on in the diet to ensure the pet is well-nourished.

With material from dpa

This article is a machine translation of the original German version of PETBOOK and has been reviewed for accuracy and quality by a native speaker. For feedback, please contact us at info@petbook.de.

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