Can Cats Be Allergic to Dogs?

I’m worried our cat could be allergic to our new dog. She’d been perfectly healthy previously, but now she’s scratching all the time and is developing some bald spots. We can’t think of anything else that’s changed in the house except adopting the puppy. Is my cat allergic to dogs?

This sounds like something a nervous new dog parent might ask, but it’s actually not a ridiculous question. Yes, cats can be allergic to dogs. Here’s why.

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Can a cat be allergic to a dog?

Cats can be allergic to almost anything, including dogs, people, and even other cats. Learning how environmental allergies work can help you understand how cats can be allergic to dogs. Allergies develop due to an inappropriate immune system response to environmental material that cats inhale or touch. This material can be almost anything: mold spores, pollen, mites, dust, or dander. Dander just consists of dead skin flakes that animals and people constantly shed. It’s maybe best not to think about that too much.

The immune system sees any organic foreign material as a potential invader and works hard to get rid of it. This strategy works well for most cats, and the outside debris is broken down and removed without incident. But cats with allergies can have an overreaction to certain materials. Their immune system goes into overdrive and has an inappropriately severe reaction to some allergens. This results in an overwhelming inflammatory response that can outlast the presence of the offending material.

Vets still don’t understand the exact mechanisms of this response in cats. Because research in this area is still ongoing, the allergic syndrome has gone through a few names as scientists try to accurately describe the disease. The condition has been called “feline atopy,” “feline atopic dermatitis,” “non-flea, non-food hypersensitivity dermatitis,” and “feline atopic skin syndrome.” Most people just call it “allergies,” though. It’s less of a mouthful.

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Allergy symptoms in cats

For cats with allergies, symptoms can range from mild to severe. You can be around your cat constantly and still miss some of the signs, because cats are tricky. That may wait until they’re unobserved to do some secret scratching. Or you may be fooled into thinking your cat is just being extra fastidious this month when they’re really grooming more because their skin itches. Some common symptoms of a cat with allergies include:

• Scratching: One of the hallmarks of allergic skin diseases is intense itchiness. There are some cats that will never show signs of this, but most will make it very obvious that it feels like their skin is crawling all the time.

• Increased grooming: Another sign of itchiness in cats is an increase in the frequency and intensity of grooming. Cats often focus on problem areas that they can reach, like their belly. The uptick in grooming can further damage the skin and set it up for problems with secondary infections.

• Hair loss: That sandpaper-like tongue probably feels great on itchy skin, but it can result in damage to the hair. Inflamed skin also may be more likely to produce unhealthy hair or lose hair from weakened follicles.

• Skin redness: The cycle of skin inflammation from allergies and increased skin trauma from itching and scratching can result in redness. This redness can be limited to problem areas like the neck, face, and belly, or it can be generalized over the whole body.

• Skin lesions: Wounds on the skin can develop due to intense scratching, frequent grooming, or bacterial or fungal infections. These bald areas are often moist, intensely red, and painful.

• Ear infections: Disruption of the skin’s normal function affects the skin lining the ear canals as well. Bacterial or yeast ear infections are more common in cats with allergies.

• Pustules or papules: These often appear early in the onset of allergic skin disease but may not be obvious as they rupture or fade into more generalized skin inflammation.

• Hyperpigmentation: Darkening of skin occurs in cats due to overgrowth of Malassezia yeast or with thickening of the skin due to repeated trauma. The grey or brown color will often fade as the infection and allergies are controlled.

• Nasal congestion: Cats seem to suffer the nasal symptoms associated with allergies less frequently than people do, but they can still occur. Rhinitis can cause sneezing, nasal discharge, and congestion.

• Respiratory issues: In addition to nasal issues, there is a potential link between skin issues in cats due to allergies and feline asthma. In one study, cats with asthma with no skin problems had more significant skin reactions to allergens than those without asthma.

Is my cat allergic to my dog?

Figuring out exactly what a cat is allergic to can be quite the undertaking. A cat can be allergic to a dog, but that’s likely not as common as other types of allergies. Even if your cat’s allergy symptoms started after you got a new dog, it’s not a guarantee that the dog is causing them. Many cats have seasonal allergies that wax and wane with time and progress with age.

The first thing is figuring out if your cat truly has environmental allergies or if something else is going on. Environmental allergy symptoms in cats are similar to those in other skin conditions. Flea-bite hypersensitivity, food allergies, mange, lice, autoimmune conditions, fly bites, and skin infections can all look like environmental allergies. Working with your vet or a veterinary dermatologist to get to the bottom of your cat’s skin issues is the best way to get them some relief.

Your vet can look for evidence of parasites that can cause skin issues or may recommend a skin biopsy of severe lesions to help rule out non-allergic causes of skin disease.When determining what kind of allergies you cat has, there are two types of tests available:

• Serum allergen testing: This type of test is easier to do; your vet just needs to send blood to an outside laboratory for analysis. It can be done even if a cat is on steroids or antihistamines. There are some concerns about the possibility of false-positive or false-negative results with different labs that do the analysis.

• Intradermal skin testing: This involves injecting small amounts of different allergens under the skin. It is a bit more intense and often requires sedation. It also requires that cats be off steroids and antihistamines completely for two to four weeks to get accurate results; it can be tough for cats with severe allergies to go without these medications. The benefits of intradermal testing are that it targets the affected organ (the skin) specifically and that there are a wider range of allergens available for testing.

There’s still some controversy about which test works best for cats, so each vet will approach testing differently. Note that serum and intradermal allergy tests don’t work well for food allergies. The GI tract seems to handle things differently, so the best way to diagnose a food allergy is by doing an ingredient elimination trial.

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How to reduce cat allergy symptoms

The benefit of having allergy testing (whether serum or intradermal) done is that you can get a profile of what exactly is causing your cat’s allergy issues. This allows for the creation of a treatment that’s specific to your cat. Allergy immunotherapy desensitizes cats to allergens through regular exposure to them. They can take the form of injections beneath the skin or a liquid given under the tongue. Although this therapy doesn’t give immediate results (it takes over three months), it is effective at controlling symptoms in over half of treated cats.

Other strategies to reduce allergy symptoms in cats include: incorporating HEPA filters into the environment to reduce circulating allergens, regular cleaning to help get rid of dust mites and materials tracked in from outdoors, and wiping down pets after they’ve been outdoors. If your cat is allergic to dogs, bathing your dog regularly can get rid of some dander before it falls off on its own.

If your cat is having a bad allergy flare-up, your vet can prescribe medication to help control their symptoms. Commonly used medications include steroids, like prednisolone, immunosuppressives like cyclosporine. Some vets think that oclacitinib (Apoquel) helps cats, though it is not labeled for use in cats and its efficacy is not proven. Antihistamines may help reduce the frequency of flare-ups, but aren’t much help once an allergy flare-up has started.

Bottom line

Skin allergies in cats can have a big impact on their quality of life and appearance. Testing to find out the cause of your cat’s reaction can help you target the specific allergens at fault. Once the allergens have been identified, your vet can target therapy to reduce your cat’s sensitivity to them and incorporate strategies to reduce their presence in your cat’s environment.

References

• Bajwa, Jangi. “Atopic dermatitis in cats.” The Canadian Veterinary Journal vol. 59,3 (2018): 311-313.

• Jensen-Jarolim, Erika et al. “Pollen Allergies in Humans and their Dogs, Cats and Horses: Differences and Similarities.” Clinical and Translational Allergy vol. 5 15. 7 Apr. 2015,doi:10.1186/s13601-015-0059-6.

• Moriello, Karen A et al. “Pilot study: prevalence of positive aeroallergen reactions in 10 cats with small-airway disease without concurrent skin disease.” Veterinary Dermatology vol. 18,2 (2007): 94-100.doi:10.1111/j.1365-3164.2007.00573.x.

• Ravens, Philippa A et al. “Feline atopic dermatitis: a retrospective study of 45 cases (2001-2012).” Veterinary Dermatology vol. 25,2 (2014): 95-102, e27-8.doi:10.1111/vde.12109.