Why So Many Dogs Have Allergies Now

9 minute read

Every day, itchy dogs shuffle into Elizabeth Falk’s veterinary office. Some can’t stop chewing their feet or scratching their bellies. Others have red, smelly ears, or rashes on their skin. All are intensely uncomfortable because of environmental allergies. “They’re sitting in the waiting room, and everyone else is backing away out of fear that it’s contagious,” she says. “It’s super busy helping as many as we can.” Until recently, Falk was a veterinary dermatologist at Cornell University Veterinary Specialists, where she saw about 15 allergic pets a day and was booked up to six months out. Demand is so high that in April, she’ll open her own pet dermatology practice.

More and more dogs are suffering from atopic dermatitis, otherwise known as environmental allergies: According to a 2018 report from Banner Pet Hospital—the latest U.S. numbers on the subject—there’s been a 30% increase in cases over the past 10 years. In 2021, a teaching hospital in Brazil reported that 25% of dogs they examined suffered from allergies. Though dog allergies aren’t consistently tracked, anecdotally, they’re soaring. “Allergic skin disease is probably the top thing we see,” says Erin Tate, vice president of clinical development at CityVet in Dallas. “I’ve been doing this for 25 years and have definitely seen a dramatic increase in recent years.” Dogs with environmental allergies tend to be “miserable,” she adds, sometimes scratching so aggressively that their hair falls out. Spring is a particularly trying time. “I tell people that if your allergies are flaring up, your dog’s allergies are flaring up, too,” Tate says.

But what’s driving the increase in itchiness? And what helps relieve allergic dogs’ agony?

Some dogs are allergy magnets

There’s a strong genetic component to atopic dermatitis, Falk says. Certain breeds are prone to them, including German Shepherds, Labrador Retrievers, French Bulldogs, English Bulldogs, West Highland Terriers, Shih Tzus, pitbulls, pugs, and Boxers. Allergies look different in different breeds. German Shepherds, for example, tend to get crusts around their lips, Falk points out, while labs develop bumps between their toes.

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Environmental allergies typically first appear when a dog is 6 months to 3 years old, says Matthew McCarthy, founder of Juniper Valley Animal Hospital in Queens, though there are outliers. Allergies are the result of skin barrier dysfunction, or a defective outer layer broken down by inflammation. “The old-school way we used to think about this was, these guys are inhaling [allergens], and they’re getting into their bloodstream, and they're reacting, and that’s what’s causing the histamine to be released,” McCarthy says. “Now, we know that’s probably not the case.” Instead, airborne allergens—like pollen from grass or trees—likely get absorbed through the dogs’ skin. That leads to symptoms such as excessive itchiness, which might prompt dogs to constantly lick or chew their feet or rub their faces. In some cases, atopic dermatitis manifests as frequent skin and ear infections rather than itchiness; an especially unlucky group of dogs experience all of the above.

Climate change plays a role

The main reason why an increasing number of dogs suffer from allergies has to do with the warming planet. “Allergy season has been extended because of climate change and the dramatic change in temperatures,” Tate says. During the winter where she lives in Texas, there might be a couple cold days in the 30s or 40s, immediately followed by a jump to the 70s or 80s. “Every time we get that warm spell in between the cold, stuff starts to bloom again,” she says. “Nothing ever gets a chance to die.”

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Research suggests that warmer weather and increased carbon dioxide concentrations extend the growing season for mold spores and plants like ragweed, while also worsening air pollution. In North America, pollen seasons now start 20 days earlier and are 10 days longer than they were in 1990. Plus, there’s an average of 21% more pollen during each allergy season. Cue the frantic calls to your pup’s vet. “Climate change is affecting humans and dogs,” Tate says.

Dogs used to get dirtier than they do now

Early exposure to microorganisms—through things like dirt, germs, and even dogs—can help protect infants from developing allergies. The same is true of dogs, says Matthew Levinson, a veterinary dermatologist who owns Pet Derm in Chicago. Research suggests that dogs who live in a rural environment, regularly go for walks outside, and have contact with farm animals are less likely to have environmental allergies, while atopic dermatitis is more prevalent in urban environments, where dogs tend to spend a greater amount of time inside.

“We’re more clean and hygienic—dogs aren’t spending as much time outside anymore,” Levinson says. “It’s not like back in the day, where you’d have a dog house in the backyard, and the dog spent most of the day in the yard.”

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Meanwhile, dogs who live in a household with other dogs also appear to benefit from a protective effect. But that doesn't necessarily mean you need to adopt another dog—or try to expose your pet to more germs. It’s difficult to tease apart all the genetic and environmental factors that contribute to allergies, Levinson says. There’s simply “too much variation between the individual dogs, and so much that’s subjective,” he says, making wholesale recommendations tricky.

A silver lining: better treatment options than ever

On any given day, Levinson treats 14 to 17 allergic dogs. He says he feels so guilty knowing how many more are suffering that he often double-books appointments. When an itchy dog arrives in his office, he first takes a detailed history: What areas of the body are itchy, and what times of the year do they flare up? He’ll do a physical exam, looking for redness in their paws and groin, and might suggest an elimination diet to rule out food allergies. Once he’s certain the dog has environmental allergies, he’ll usually advise allergy testing. That means he injects dozens of small amounts of allergens under the dog’s skin, and if the pup is allergic, a hive will form at the site, pointing to the culprit.

Managing allergies is a “marathon, not a sprint,” Levinson stresses, and most dogs require lifelong treatment. There’s no cure, but treatment options are far better now than they were even a decade ago. The majority of dogs respond well to immunotherapy: customized injections, just like the allergy shots humans receive, that train the immune system to become desensitized to certain allergens. It could, however, take more than a year to see results.

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There are other options. In 2013, an oral medication called Apoquel was approved to control itchiness and inflammation in allergic dogs. “It was like a miracle,” Falk says. “We had been waiting for it for so long.” It’s safe and well-tolerated, she adds, and is a “reasonable long-term medication” for itchy dogs who get skin infections.

A few years later, in 2016, another treatment option came on the scene: Cytopoint, a targeted therapy that’s administered via injection every four to eight weeks. It’s a monoclonal antibody to an itch signal called interleukin (IL)-31, Falk explains. “It binds to that itch signal,” she says. “It doesn’t affect the rest of the immune system in any way, which makes it very safe.” The downside, she adds, is that it’s only intended to control itchiness—so allergic dogs prone to infections caused by inflammation will still get them. That’s why it’s important to align medication choices with how a dog manifests allergies: Itchy dogs who never get infections usually do best on Cytopoint, while Falk often prescribes Apoquel for those who do develop infections, since it’s a good anti-inflammatory choice.

However, doggy dermatology doesn’t come cheap, and pet insurance typically only covers treatment if dogs are insured before they become symptomatic. Allergy testing can cost upwards of $1,000 out of pocket, Apoquel is about $90 for 30 tablets, and a Cytopoint injection can range from $50 to $200, depending on the dog’s size.

Is there any way to prevent allergies?

Having an allergic dog typically boils down to bad luck. If a dog is born predisposed to itch, he’s going to itch. But if you’re considering buying a puppy from a breeder, it can be helpful to ask them if there are any allergic dogs in a potential pet’s pedigree, Falk advises. Research suggests that when two dogs with atopic dermatitis are bred, 65% of their offspring will have environmental allergies; if just one parent has the condition, that drops to 21% to 57%; and if neither parent has allergies, 11% will go on to develop problems.

If your dog has allergies (and even if they don’t), make it a point to bathe him regularly—about once a month—to remove potential allergens from the skin, Tate advises. She thinks of dogs as “little dust mops” who pick up a lot when they’re gallivanting around outside. Some people like to wipe their pets down with unscented baby wipes to get the pollen off, she adds.

And, most importantly, if your dog is suddenly scratching a lot more than usual, take him to the vet. Depending on the severity of the situation, your vet might refer you to a specialist, but many cases can be handled by your regular vet. “The earlier you get started with immunotherapy, the better the success rate,” Levinson says. “When the dog is younger, you can mold the immune system a lot easier, versus if you have a dog who’s had allergic symptoms for several years.” The sooner you get on top of your dog’s health, he stresses, the happier you’ll both be.

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