5 March 2025
Allergies in Cats
Anyone with allergies would agree that they’re no picnic. Unlike illnesses, in which the body's immune response is responsible for fending off, an allergy occurs when a cat’s immune system reacts (or overreacts) to a particular substance. Any substance that causes an allergic reaction in cats is called an antigen or an allergen.
In this article, we look at some of the most common allergies in cats, how to spot the signs of allergies in cats and how to manage your cat’s allergies.
What Causes Allergies in Cats?
Several different things can cause allergies, which are quite common in cats. It is very rare for a cat to be born with an allergy. Instead, allergies develop over time because of exposure to particular allergens, including food, pollen, and dust.
Some cats can also develop allergies to multiple allergens at once, which can make diagnosis tricky. However, you can learn how to manage cat allergies without a diagnosis. However, prescription allergy treatments for cats are only available if you’ve received a diagnosis from your vet and a valid prescription.
While allergies are rarely a life-threatening condition, they can be lifelong, meaning learning how to spot the signs of allergies and manage them is essential for any current or prospective cat owner.
Allergy Symptoms in Cats
There are several symptoms of allergies in cats, but the most common signs are inflammatory responses caused by the immune system, such as:
- Itchy skin (causing excessive scratching or licking, which may lead to cats overgrooming the area)
- Sores, scabs, lumps, bumps, or hives on the skin
- Flat or swollen skin
- Poor or unkempt coat (patches of hair loss are also common)
- Coughing, wheezing, trouble breathing, shortness of breath.
- Sneezing, watery discharge from the nose.
- Stomach upsets (such as vomiting, diarrhoea, blood in stool, change or loss of appetite)
- Facial swelling, particularly around the nose, mouth, or eyes.
- Anaphylaxis (in rare cases)
Note: It is a medical emergency if your cat is having difficulty breathing. You should contact your vet as soon as possible to have your cat examined. Anaphylaxis, while rare in cats, is also a medical emergency, and you should seek emergency veterinary help as soon as possible.
Common Allergies in Cats
Like humans, cats can be allergic to numerous substances, but veterinarians typically recognise four main types of cat allergies. These are:
- Food Allergies
- Atopic Dermatitis (environmental allergies)
- Flea allergy dermatitis (allergies to flea bites)
- Allergic contact dermatitis (a rash caused by allergens making direct contact with your cat’s skin)
In addition to the above, cats may also suffer from allergy bronchitis (feline asthma), which affects between 1 and 5% of cats, and skin reactions to medications (also called cutaneous drug eruptions).
It’s important to remember that cats can have more than one of these allergies at any one time, which can make finding the root cause a bit tricky.
Below, we delve into each of these main allergy types to help give you a better understanding of what may be causing your cat’s symptoms. If you think your cat may be suffering from any of the allergies mentioned above, it’s imperative you consult your vet as soon as possible to begin a treatment regime.
Food Allergies in Cats
One of the most common allergies in cats is food allergies. Food allergies occur when a particular ingredient(s) in a cat's food triggers the cat's immune response. Some cats, such as Siamese cats, may be more prone to food allergies because of their breed.
Most cats have allergies to a particular protein (such as chicken, beef, pork, etc), although cats can be allergic to any protein, carbohydrate, preservative, additive or dye in their food. This can make finding the food allergen affecting your cat tricky, which is why some vets may recommend a food elimination trial to try and find the allergen responsible.
Food elimination trials take a long time—sometimes months—to complete and should only be done under the supervision of your vet.
To conduct a food elimination trial, you’ll need to do a couple of things:
- First: Switch your cat to a hypoallergenic or anallergenic food, like this ROYAL CANIN® Veterinary Health Nutrition Anallergenic Dry Cat Food. You must also ensure your cat eats only their elimination trial food for the duration. This means restricting treats to hypoallergic ones only and preventing your cat from eating anything that could compromise the trial. (e.g. human leftovers, bin scraps, and anything else they might eat)
- Next: Monitor your cat’s condition while eating the new hypoallergenic food. If a food allergy is responsible for the allergic response, the symptoms should ease within a few weeks.
- Then: Begin to slowly introduce potential allergens one at a time back into your cat’s diet. For example, you could offer them some cooked chicken to see if that triggers an allergic response or try reintroducing grains like wheat. If your cat’s symptoms don’t return after eating the potential allergen, make a note of it and continue on.
This can be a very slow process, and it can take up to twelve weeks to get an answer. However, if your cat eats anything not included in their elimination diet or excluded from the potential allergens list, the trial has to start all over again because of cross-contamination.
How to Treat Food Allergies in Cats
Once you and your vet have determined the allergen your cat is responding to, such as a chicken allergy in cats, the key to managing their condition is to ensure they don’t eat anything that contains that allergen. Depending on their allergy, this might mean switching to a hypoallergenic cat food or grain-free cat food.
Flea Allergies in Cats
An allergy to flea bites, also called flea allergy dermatitis, is when your cat’s immune response is triggered by flea saliva. That doesn’t necessarily mean your cat is infested with fleas because it only takes one bite to cause an allergic reaction. Plus, with cats being such fastidious groomers, finding live adult fleas or flea dirt in their coats can be tricky, especially if only one or two fleas are biting your cat.
While cats with fleas may display symptoms similar to flea allergy dermatitis, like itching, chewing, or overgrooming, the symptoms will be much more pronounced if a flea allergy is the culprit. Most cats who suffer from a flea allergy will focus on the area just before their tail, with some even licking the hair off their legs. Fleas are also commonly found around a cat's neck and neck, so check these areas for small scabs that look like millet seeds if you think fleas might cause your cat's allergies.
How to Treat Flea Allergies in Cats
The best way to treat cat flea allergies is to eradicate potential fleas on your cat and in your home. Maintaining a strict parasite prevention plan can help you prevent allergy flare-ups, as any fleas that land on your cat will die before they can bite. We recommend using a spot-on cat flea treatment that kills fleas on contact, like the Advantage for Cats Spot-on Flea Treatment, or a long-term flea treatment, like the Seresto Flea and Tick Collar for Cats.
If your cat is infested with fleas, our Complete Guide to Getting Rid of Fleas provides further advice on managing the infestation.
Seasonal Allergies in Cats
Another common allergy in cats is environmental allergies, also called atopy. Atopy in cats can be caused by several potential allergens including, but not limited to:
- Pollen
- Dust
- Mold or spores
- Yeast
- Storage mites
- Animal or even human dander
Atopy in cats is characterised by itchy and inflamed skin and may be more present in certain breeds, such as Abyssinian and Devon Rex cats, and domestic short-hair cats under 3 years old.
How to Treat Seasonal Allergies in Cats
If your cat is suffering from atopy, the key is to minimise their exposure to allergens.
Unfortunately, you can’t allergen-proof your home, as dust accumulates naturally, and pollen can easily be brought in on clothes, shoes, or open windows. Instead, you can minimise your cat’s contact with allergens by:
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Dusting and/or vacuuming more frequently, especially where your cat spends the most time
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Using dust-proof materials such as plastic and wood for furniture
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Washing your pet’s bedding weekly on a hot wash (at least 60 degrees Celsius)
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Avoid having too many pillows or throws, and wash these regularly, too.
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Wash your cat’s soft fabric toys and clean cat furniture more regularly.
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Wiping your cat’s face after feeding with a pet-safe wipe like these CLX Wipes®.
Depending on the severity of your cat's seasonal allergies, your vet may also suggest treating the condition with antihistamines, which they will advise on.
You can also manage your cat’s allergy symptoms with cat allergy treatments like this Allerderm Spot-On treatment to help nourish your cat’s skin and help alleviate skin problems associated with allergies.
Allergic Contact Dermatitis in Cats
Allergic contact dermatitis is a delayed reaction from the body’s immune system after the skin comes into contact with a particular substance. While rare in cats due to their strict grooming habits, allergic contact dermatitis can occur if your cat’s skin makes contact with:
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Plants (including pollen, grasses, and trees)
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Medications (such as spot-on treatments, ear medications, soaps and shampoos, and insecticides)
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Home furnishings (certain fibres, dyes, polishes and cleaners can cause allergic contact dermatitis in cats)
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Other substances (such as rice flour or chlorinated water from pools or water features)
The symptoms of a contact dermatitis in cats include many of the allergy symptoms mentioned, such as itchy or flaky skin, rashes or sores, and hair loss, but only at the spot where the allergen or substance came into contact with the skin.
How to Treat Contact Dermatitis in Cats
As with other allergies, there is no sure cause for contact dermatitis. However, it can be treated. Your vet will decide the necessary treatment for contact dermatitis depending on the severity of your cat’s reaction to the substance. This treatment may include:
- Medicated shampoos
- Topical anti-itch treatments
- Allergy medications
- Steroids
Contact dermatitis may also cause secondary infections if left untreated, so contact your vet if you notice anything abnormal with your cat’s skin.
How to Treat Allergies in Cats
There are no cures for allergies in cats, but they are manageable with the right treatment and care. Depending on the type and severity of the allergies, various cat allergy treatment options are available, including non-prescription allergy treatments intended to soothe their symptoms.
Cat allergy treatments may include:
- Changing foods
- Antihistamines
- Immunosuppressive therapy or drugs
- Immunomodulating drugs
Any treatment options for your cats' allergies should first be discussed with your vet. They will assess your cat’s condition and recommend the appropriate treatments, such as prescription allergy treatments.
Cat Allergy Supplements
As most allergies in cats cause skin reactions, you can help soothe their symptoms by introducing skin and coat supplements packed with Omega 3 and Omega 6 Essential Fatty Acids, like this COATEX® Essential Fatty Acid Skin and Coat Supplement. These fatty acids are essential for nourishing your cat’s skin and helping to maintain their skin’s integrity.
Cat Allergy FAQs
Can Cat Litter Cause Allergies in Cats?
Yes, certain types of cat litter, particularly dusty cat litter. Cats with allergies to their litter may display symptoms like itchy skin, breathing problems, and sneezing.
If you suspect your cat is allergic to their litter, we’d recommend switching to a new, dust-free cat litter, like this FRESH NEWS® Recycled Paper Cat Litter, which is 99% dust-free and 100% non-allergenic.
Can Cats Develop Allergies Later in Life?
Yes! There is no time limit on when cats might develop allergies. Food allergies and environmental allergies can be common in cats later in life, particularly those between 4-5 years old.
How Long Does Flea Allergy Dermatitis Last in Cats?
How long flea allergy dermatitis lasts will depend on your cat’s sensitivity to the flea bites, and how many times your cat has been bitten. With treatment, flea allergy symptoms can start improving within a few days, but it may take a couple of weeks to fully recover.
What is The Most Common Food Allergy in Cats?
Proteins are the most common food allergies in cats, specifically chicken, beef and fish. Dairy products are another common allergen to be aware of in cats.
Do Cats Allergies Get Worse in Spring?
If your cat has environmental allergies, they may worsen in springtime as pollen levels are higher.
Between March and May, tree pollen from birch and hazel trees is at its highest. From June to August, grass and weed pollen is higher, with weed pollen levels peaking in September. Depending on what environmental substance your cat is allergic to will impact when their flare-ups are at their worst.
No matter your cat's allergies, find the best cat allergy treatments, including skin and allergy supplements and hypoallergenic cat food, at great prices from Pet Drugs Online. You can browse our full range of cat allergy treatments now with fast delivery as standard.
This post is an opinion and should only be used as a guide. You should thoroughly discuss any change to your pet’s care or lifestyle with your vet before starting any program or treatment.
