Pets, Places, & Things, Points on Pets

Cats and Allergies

By Jaime Stephens

Cats, like people, frequently suffer from allergies.  The most common of these is caused by fleas, which should be no surprise to anyone with pets.  But did you know that the allergic reaction in their immune system is caused by the histamine-like agents from saliva that are released when a flea bites your pet?  The number one reaction to flea bites is itching, but other allergic symptoms include scratching, particularly the head and ears; chewing and biting themselves; excessive licking (especially around the legs); and red and/or irritated skin (allergic dermatitis). Cats are such fastidious groomers, however, that it’s fairly difficult to find traces of fleas on their bodies.  It’s much likelier that you’ll notice fleas jumping around in your house or even on your body before you see them on your cat.

The best way to treat a cat with skin allergies due to flea bites is by using a topical or injectable corticosteroid.  If the cat develops a skin infection, these may be treated with antibiotics.  Prevention, however, is key – consider using a topical or oral medication or flea collar.


Did you know that pets can also suffer from seasonal allergies?  They can, with symptoms that closely mimic those that humans experience. The same irritants that trigger seasonal allergies in humans do the same to cats and dogs, and both indoor and outdoor cats can be affected.

When do cats experience seasonal allergies?  During any season! One may have summer allergies while another may have winter allergies, and some cats suffer from year-round allergies. During the spring and summer months, the most common cause of allergies is pollen from trees, grass, and weeds. In the fall, ragweed is typically the culprit. With seasonal allergies, symptoms are usually skin irritation and/or inflammation.  In some instances, respiratory problems such as a runny nose, watery eyes, and coughing and sneezing may occur.

Your vet may prescribe steroids for seasonal allergies, which have minimal side effects in cats and are usually effective at relieving allergy symptoms. Steroids do not, however, provide a cure for the allergy, which will return with exposure to the allergen. Another treatment option is desensitization therapy, which  involves repeated exposure to small amounts of the allergen in a controlled environment. Multiple treatments are required in which allergen exposure is gradually increased, until the cat’s immune system is “trained” not to react to the allergen. This treatment is time-consuming and fairly pricey, however, it is usually effective, and, if successful the allergy will not recur or require further treatment seasonally.


According to studies, food allergies are the third most common allergies in cats. The foods typically associated with food allergies in cats include beef, fish, chicken, turkey, and dairy. A cat needs to have been exposed to a food ingredient before developing an allergy to it. An ingredient a cat has consumed for a long time can still cause an allergy at some point in the cat’s life, as it can in humans.

Symptoms include chronic, year-round itching and skin inflammation. This itching typically affects the face, ears, belly, groin, armpits, legs, and paws. This can be so itchy that cats often overgroom themselves, causing significant trauma to their skin (wounds, abrasions) and hair loss. Affected cats may also develop recurrent infections of both the skin and ears. In some cats, these infections may be the only clinical sign of food allergies. Cats with food allergies may also develop gastrointestinal signs such as vomiting or diarrhea in addition to their skin symptoms. The most visible signs of a food allergy—the persistent scratching, the emergence of skin lesions, loss of hair, and a general deterioration of the coat—do not develop overnight. Instead, they tend to become evident and intensify over extended periods of time—months or even longer—as the animal’s immune system gradually mounts a defense against certain protein and carbohydrate molecules that are present in most standard cat foods. According to vets, a cat of any age can be affected, and it can occur in a cat that has been on the same diet for years.

When the signs appear, a cat should receive prompt veterinary care. If a food allergy is indeed suspected, the specific allergen should be identified and removed from the animal’s diet. If your cat has a true food allergy, then any sensitive stomach issues should clear up in 2 to 4 weeks. External symptoms like itchy skin will take longer to resolve.


Asthma is more common in cats than in dogs, but relatively undiagnosed.  Young cats, as well as Siamese and Himalayan cats, are the most commonly diagnosed with feline asthma.  Symptoms of asthma in pets includes shortness of breath, wheezing, and difficulty exhaling.  In cats with asthma, lung tissue that is inflamed causes air to get trapped, resulting in difficulty breathing.

Although related, allergies and asthma are different; allergies can trigger an asthma attack and exposure to allergens can make an asthma attack worse.  The good news, though, is just because your cat has allergies does not mean they will develop asthma.

As always, consult your veterinarian at the first sign of any suspected allergic reaction.

About the Author: Jaime Stephens is a frequent contributing writer who lives with her husband John and their cats in Alexandria.


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