White cat with food bowl

Cats with allergies can show skin signs, such as itchy skin.

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What is hypoallergenic cat food?

By Dr. Liz Barton MA, VetMB, MRCVS Veterinarian

Updated on the

Changing your cat's diet to hypoallergenic cat food is one way that could help reduce your pet's allergies.

Certain cats can be allergic to all sort of things, including certain foods, which can lead to them vomiting or having diarrhoea. Yet which foods a particular cat is allergic to depends totally on the individual animal. One answer to solving the allergic reaction is to change their diet – probably with the help of a vet. Another is to try them on hypoallergenic cat food, which is food for them that is relatively unlikely to cause an allergic reaction.

What is the best hypoallergenic cat food?

To be truly hypoallergenic, cat food needs to be broken down so there are no large protein that may cause an allergic response. These foods – known as hydrolysed diets – contain smaller proteins, less likely to trigger an immune response.   

What ingredients in cat food cause allergies?

With all allergies, cats are most commonly allergic to things they are frequently exposed to. Beef, chicken, seafood, egg, dairy and gluten are common triggers. It is also common to be allergic to more than one type of protein and often the exact ingredient triggering the allergy is unknown.

There is no accurate data on how common food allergies are in cats, because the underlying cause of allergic response can be difficult to diagnose – often there is more than one allergy trigger for an individual cat. Food allergy is thought to affect 1 to 11 per cent of cats with skin conditions, in various studies.

How can I tell if my cat is allergic to their food?

Cats with food allergy may show gut signs, including diarrhoea and vomiting. They may also suffer from itchy skin and present with hair loss and scabs. The only way to prove the food is the cause is to exclusively feed a novel source of protein and carbohydrate – or a hydrolysed diet – for 12 weeks. If the symptoms disappear, then food allergy is likely to be present.

What protein are cats most allergic to?

Beef, chicken, seafood, egg, dairy and gluten are common food allergens in cats.

What is the best food for cats with allergies?

A hydrolysed diet should be the least allergenic for your cat. But they are expensive to produce and not often the tastiest food and some cats won’t eat these diets. The best diet for your cat may be one with a novel protein source, which does not trigger allergy, such as duck or venison. It’s a case of trial and error to find a diet your cat likes to eat, which does not trigger allergies.

How do I know what my cat is allergic to?

The only way to prove a food allergy is to feed a novel or hydrolysed diet until the allergy symptoms have gone away completely. Then by reintroducing a protein, such as chicken, on its own and seeing if this causes the symptoms to return will show whether it truly is an allergic trigger. This diet ‘challenge’ step is often skipped, as when a cat is settled on a diet few people want to feed a diet to see if the allergy returns.

Allergens that are not eaten but inhaled, such as grass pollen and house dust mites, can be diagnosed with an intradermal skin test with a veterinary dermatologist, if they cause itchy skin. Blood tests can also be used to check for antibody levels to certain allergy triggers, but these are not always reliable as antibody levels can vary.

Can a cat be allergic to cat litter?

Cat litter may cause adverse reactions even if they are not truly allergic. Some cat litter contains chemicals, bentonite, silica dust, clay and fragrances that may irritate the airways or skin through contact allergy. This may lead to litter box avoidance. If your cat suffers from asthma, then dust particles in the litter may trigger difficulty breathing. Using litter with low dust content can reduce the risk of breathing problems.

Can clumping cat litter make cats sick?

Clumping cat litters absorb liquid to clump. Theoretically, cats ingesting large quantities could suffer from obstruction in the gut, if the litter were to clump internally. In reality, most cats may ingest small amounts from cleaning the litter from their feet and fur, but it is very unlikely for them to eat enough to cause a clinical problem. Kittens may ingest more out of curiosity, so it is best to avoid clumping litters until they are older (and wiser). Perfumes, anti-odour chemicals and dust in clumping litter may cause allergic or irritant reactions.

What are the symptoms of a cat with allergies?

Cats with allergies typically show skin signs, such as itchy skin, overgrooming and hair loss; or gut signs including vomiting and diarrhoea. They can also show breathing signs, as cats can suffer from asthma.

What is the best cat litter for cats with allergies?

A low dust cat litter with minimal chemical perfumes is the best for cats who show sensitivities. Pellets made from rolled-up recycled newspaper or compacted wood are good options.

When should I see a vet?

It is important to see a vet if your cat suffers from diarrhoea or itchy skin that has been persistent for a few days.

What should I ask a vet about the best diet plan for a cat with allergies?

If you think your cat has an allergy, it is important to tell the vet about what you feed your cat – including all the treats and tit-bits. Knowing when the allergy started and what makes it worse can also guide what is most likely to be the cause. The vet may want to rule out common causes of allergies before starting a diet trial, for example flea allergy, if your cat has itchy skin. They may also want to take and check a faecal sample for parasites and gut infections, if your cat has vomiting or diarrhoea.

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