Twice as many people are allergic to cats as to dogs, according to the American College of Allergy, Asthma, and Immunology. With pet cats residing in almost 50 million households in the United States, that’s a lot of sneezing, wheezing, watery eyes, runny noses, and other uncomfortable symptoms to be with the felines we love.
But guess what? Cats suffer allergic reactions, too, with the same sneezing and wheezing, often accompanied by itching so bad that it leads to vehement scratching and subsequent skin lesions. Sometimes cats whose allergies cause itching or related discomfort on their paws chew on them so vigorously that their paws end up swollen.
What proportion of cats have allergies? One study estimates the number is somewhere around 15 percent. Since there are almost 100 million pet cats in the U.S., that means about 15 million of them have to contend with allergy symptoms. It comes to one cat out of every six or seven. One of them may very well be yours. Certainly, says Tufts veterinary dermatologist Ramón Almela, DVM, “many cats are referred to our dermatology clinic because they are itchy or have skin lesions compatible with allergies.” Adds Tufts veterinary internist Michael Stone, DVM, allergic symptoms in cats “are one of the most common reasons for evaluation.”
Things cats are allergic to
“Fleas by far” cause the most allergic reactions in cats, says Dr. Almela. It’s a common misconception that house cats can’t get fleas because they don’t go outside, he says. But they often make their way into people’s homes, not as fleas but as flea eggs, on shoes or on the back of the family dog. It does not mean you keep a dirty home. Fleas happen.
Second to fleas in triggering allergic reactions in felines are airborne allergens. These are often the same ones that cause allergy symptoms in people: dust mites and pollen. Other instigators include perfumes and household cleaning products. Cigarette smoke can predispose a cat to suffering an allergy or make an allergy worse.
In some cases, cats are allergic to certain foods. Cats can only be allergic to proteins, and that tends to be what they are exposed to. Think chicken, beef, fish. In addition to the symptoms of other allergies, allergies to foods can cause vomiting and diarrhea.
People will say their cat can’t be allergic to a certain food because the pet has eaten it his whole life and never had a problem. But that, too, is a misconception, Dr. Almela says. A cat can develop an allergy to a particular food (or other substance) at any time of life.
Diagnosing an allergy
As is often the case, you will be the first healthcare worker to detect that something is wrong. If your cat is wheezing or coughing or has watery eyes, a rash, hives, or other symptoms that seem like an allergy might be interfering with her comfort, you should take her to the veterinarian for a professional evaluation.
Unfortunately, says Dr. Almela, there are no reliable serum allergy tests for felines. Diagnosis is made by the process of exclusion. Adds Dr. Stone, you want to rule out problems like infections, which can also cause itchiness.
Sometimes allergies are seasonal, just like they are in people. That is, your pet may be allergic to pollen, grass, or weeds.
To nail the instigating substance, the doctor may ask you to keep a log of when your cat appears to develop symptoms and work backwards from there. It could take some sleuthing ingenuity — for instance, assessing whether your cat starts to feel sick when you use a certain household cleaning agent or wear a certain scent.
Treating the allergy
No matter what the problem substance might be — and even if it’s determined that a cat’s symptoms are not the result of an allergy — the veterinarian should be making sure that your pet is on scheduled doses (usually monthly) of flea and tick medicine that you apply yourself at home.
Brands Dr. Almela recommends include Bravecto, Revolution, and Advantage II. They are all topicals containing active ingredients that kill fleas and ticks when those bugs bite the cat. Instead of a topical, you can also choose a collar. One made by Seresto lasts 8 months.
It’s important to avoid flea and tick preventatives that contain permethrin or pyrethrins, Dr. Almela advises. They kill fleas and ticks by destroying their nervous systems, but they are dangerously toxic to cats’ nervous systems as well and can keep them from functioning properly.
Beyond flea control
If it’s determined that your cat is allergic to certain chemicals either in your cleaning products (including dryer sheets) or personal care items — perfume, deodorant, shampoos, conditionings, styling gels — the solution is straightforward. If you stop using the item, the allergy symptoms should disappear.
But oftentimes, the offending agents are determined to be airborne agents like dust mites or grass, which you can’t make go away. In such cases, medicine can help mitigate symptoms. “Corticosteroids are the mainstay of treatment initially,” says Dr. Almela (along with flea preventatives), but they come with untoward side effects, including but not limited to increased thirst and urination, increased hunger, and a general loss of energy. “Over the long term we try to switch to other drugs with fewer and less intense adverse effects,” the doctor says.
One of those is cyclosporine, Dr. Stone remarks. If the allergy is seasonal, chances are good that you will not have to administer medications all year.
What also helps cats allergic to airborne allergens is frequent vacuuming of rugs, upholstery, curtains, and other fabrics along with frequent wipedowns of surfaces with a wet cloth — a couple times a week. The more that gets sucked up into the vacuum cleaner or a wet cloth, the less that gets into your pet’s system.
In the rare case that a food ingredient might be causing the allergy symptoms, a veterinarian will help you try an elimination diet for as many as 8 to 12 weeks to see if feeding meals that don’t have any of the suspected ingredient makes the symptoms disappear. During this process, if you have more than one pet in the house, you have to make certain that your allergic cat is not getting into the other animals’ food. Even a very tiny amount can trigger an allergic reaction, and then you are back to square one as far as determining whether food is in fact the culprit.
If you follow the elimination diet strictly and there are no unpleasant reactions, your vet can prescribe a diet that will not have any of the offending substance. If your pet is very sensitive, a therapeutic diet purchased from the veterinarian rather than bought over the counter may be necessary, as the cat can react to even microscopic cross-contamination from other foods processed in the same facility.
Bottom line: If your cat is suffering from what appears to be an allergic reaction with the same symptoms a person would get, or if she is scratching herself crazy, take her to the doctor. While you can’t cure the allergy, there’s much that can be done to cut down on, and even eliminate, the symptoms.
Once in a while, cats have an allergic “contact” reaction to plastic — their plastic bowls, specifically, with which they are in frequent touch. They end up with pus-filled bumps around their chins. If that’s the case, the solution is easy. Switch the bowl for one made of metal or ceramic.