Food allergies in cats

Cats can develop an allergy to certain ingredients in their food at any point in their lives. Around 1% of all cats and 15% of itchy cats have food allergies. The most common signs of food allergies are itchy skin, ear infections, and stomach upsets such as vomiting and diarrhoea. 

Food allergies are also called cutaneous adverse food reactions or food hypersensitivity. They cannot be cured but can be managed well, and cats can live a full, happy life. Some cats may need medication to help with severe flare-ups, but most can be managed with a special diet alone.



What are food allergies in cats?

The cause of these allergies is an overreaction of the immune system to a food or ingredient that it has already been exposed to.

  • Any ingredient, but most commonly the protein source (i.e. chicken, dairy, or fish) can cause a reaction.
  • Your cat can be allergic to one or more ingredients in their food.
  • A food allergy involves the immune system, whereas a food intolerance does not. Food intolerances are more common and tend to be less severe.
  • Food allergies can occur at any age, even if they have been on the same food for years.
  • Once the allergy has developed, it cannot be cured but can be managed to stop or reduce the symptoms.

Food allergies can cause severe symptoms. If you suspect your cat has any allergies, speak to a vet for advice and to form a treatment plan to help improve their health. Our Joii vets are available 24 hours a day, call us now for advice.



Symptoms of food allergies in cats

It’s not always easy to tell if your cat has food allergies. The signs might not be seen daily, can be vague, and are often linked to other allergies.

Skin signs often start around the head, face, and neck and include

  • Itchy skin and overgrooming
  • Hair loss, red skin, rash, ulcers and plaques
  • Swollen lip or chin
food allergies in cats
Itching and scratching is a common sign


food allergies in cats symptoms
A swollen lip is a common sign of allergies in cats

Signs can affect other parts of the body too

  • Itchy ears and ear infections
  • Gastrointestinal signs such as vomiting, soft stools or diarrhoea, hairballs, and weight loss
  • Lethargy
  • Respiratory signs such as sneezing, wheezing, rhinitis, or asthma.
signs of food allergy in cats
Red and itchy ears can indicate your cat has an allergy


Find out more about what else can make your cat itchy



Are some cats more at risk of food allergies than others?

Food allergies can affect cats of all ages, breeds, and sexes. The following may be more at risk

  • Breeds: Siamese and Siamese crosses.
  • Age: It can occur at any age but is more common in younger cats (in up to 50% of cases, signs start when they are under 3 years old).



How are food allergies diagnosed in cats?

The diagnosis of food allergies can be tricky, and it is often a process of elimination. Cats may have other illnesses that are linked, such as environmental allergies (atopy) or flea allergy.

The following tests can help rule out other conditions:

  • A thorough physical examination
  • Skin scrapes, hair plucks and skin biopsy
  • Blood and urine tests
  • Intradermal allergy testing
  • Imaging of the abdomen, such as x-rays or an ultrasound
  • Stool tests


Elimination diet trial

An elimination diet trial is used to help diagnose food allergies in cats

  • Outdoor cats will need to kept indoors throughout the trial.
  • A hydrolysed protein or novel protein diet is used for at least 6–8 weeks to assess the response. A novel protein is one that your cat has never been exposed to before.
  • No other food, including treats, supplements or chews, should be fed during the trial.
  • If the symptoms resolve during the trial, it indicates a food allergy. A re-introduction challenge to their old food which causes the symptoms to return confirms the diagnosis.
  • Partial improvement of the symptoms indicates that there is not only a food allergy but also a concurrent allergy to something else.
  • At the end of the trial, a veterinarian can advise you on the next steps.

food allergy cat not eating


Most foods that are used for food trials can be used long-term too.


Vet treatment

Vet treatment for food allergies in cats

Allergies in cats can be very complex. A multimodal approach is often needed to treat allergies. This involves using different products, including special food, medications, and supplements, to help control the symptoms.

Initially, your cat may need

  • Anti-itch medication, such as steroids, anti-histamines, and Atopica.
  • Antibiotics for any skin, ear or gastrointestinal infections
  • Parasite control for any fleas or mites
  • Pain relief

Once under control, most cats with only food allergies can be managed alone with a special diet.

If the condition is complicated or not responding to treatment, your vet might refer your cat to a skin specialist (Dermatologist).


Home treatment

How to look after a cat with food allergies at home

Feed your cat a complete and balanced diet in the long term, avoiding any known allergens, such as

  • Hydrolysed protein diets contain proteins that are broken down into tiny pieces to avoid an immune reaction. Hills Prescription diet z/d is a hydrolysed diet that is clinically proven to reduce symptoms from food allergies and is used for food trials and long-term.
  • A novel protein diet contains proteins that your cat has never been exposed to. These are usually the lesser-used sources, such as venison, duck, and insect content. Such as Hills Prescription diet d/d.
  • A home-made diet is also possible. Only under direct advice from a veterinary nutritionist; otherwise, it can be unbalanced and lead to deficiencies.

Clean their ears regularly

  • Use a vet-recommended ear cleaner once every 7-10 days to keep the ears clean and prevent infection. Cleaning the ears out too often can create problems too.

Skin supplements and special shampoos

  • Supplements containing omega oils can help reduce itching and support the skin barrier.
  • Shampoos can protect and soothe irritated skin.

Probiotics for soft stools or diarrhoea

  • Probiotics usually come in paste or granules and help soothe the digestive tract as well as replenish the natural bacteria.

If your cat is very itchy, a buster collar or pet medical suit can prevent self-trauma.

Speak to a vet before starting any supplements or ear cleaners as they are not always appropriate for every cat.

Our Joii vets are available 24 hours a day for advice.


Tips on how to prevent food allergies in cats

Unfortunately, it is not possible to prevent food allergies in cats.

If your cat has any symptoms of itchy skin, ears, or stomach upset, speak to a vet as soon as possible to find and treat the cause. Our Joii vets are available 24 hours a day for advice.


Is my family at risk of catching food allergies?

Food allergies in cats do not spread between cats or from cats to humans.


When to worry

When you should be worried about food allergies in cats

Seek help from a vet if

  • Your cat is constantly itchy
  • Your cat has severe vomiting and diarrhoea, especially if there is blood
  • Your cat is lethargic and losing weight

Call us and speak to one of our Joii vets if

  • You want to do a diet trial for your cat
  • You have any questions about your cat’s short or long-term nutrition
  • Your cat has mild vomiting or diarrhoea
  • Your cat has mildly itchy skin or ears
  • You have any questions about the best skin supplements, shampoos or ear cleaners to use
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