Dog Allergies Treatment Options — Get to the Bottom of the Itch

Some dogs itch because they are allergic to what is growing outside. Two other common culprits: flea or food allergies. Seek treatment now.

Spring is upon us. I’m in Washington, D.C., right now, and yes, I missed most of the cherry blossoms. But the dogwoods and the redbuds and the azaleas and lilacs are all in bloom, as are a million other potential allergens. You may be sneezing and your dog may be itching.

Spring (and fall) are the most allergic seasons for dogs because the majority of canine allergies are inhalant allergies that manifest in itching. Dogs like yours itch because they are allergic to what is growing outside. (They can also be allergic to molds growing inside, dust mites, etc.)

For people, these “hayfever” seasons produce respiratory symptoms; for dogs, skin symptoms.

Flea allergy and food allergies are the other two most common reasons for a dog to be a chronic scratcher. (Next week I’ll discuss cat skin allergies.)

My Dog Never Had a Flea

Today this might be true. And what a relief for fleabags! With the invention of products like Advantage and Frontline, skin problems in dogs have improved tenfold. Before these products, my late summer/early fall appointment schedule was filled with dogs with severe flea-allergic dermatitis. They were scratching until their skin bled.

The owners’ homes were infested. The owners were being bitten. It was a vicious cycle. People used worrisome products on their dog  and were often forced to use harsh chemical insecticides to rid their homes of severe flea infestations. The dogs had to be treated with steroids, antibiotics, flea shampoos, ointments, sprays, dips, you name it. It was a nightmare.

This poor pup has fleas.

Despite the revolutionary improvement in flea prevention, dogs still get fleas and flea allergy. I have come across the occasional Birkenstock-and-sock-clad client who doesn’t believe me. Telling them their dog has fleas is like telling them their child isn’t gifted.

Often I have to find the flea, or at least find the flea feces, and stick it under their fragrance-free nose to convince them that yes, their dog has fleas! After I listen to the suggestion that their dog must have caught that one and only flea IN MY CLINIC, I try to persuade them to treat the fleas before the problem gets out of hand.

No Fleas, Now What?

When presented with an itching dog, I obviously examine the patient’s skin, the lesions, the pattern, etc. Then the first question I ask is, “When does your dog scratch?” After the client says 24/7, I ask them to narrow down the time period. Very frequently, the dog has been itching for the past two weeks. I check the chart, and remind the client that they were in my clinic a year ago, same time, same complaint.

If we can determine that the dog has transient itching for maybe a month or two out of the year, and for the rest of the year he never scratches, we probably have a diagnosis of seasonal skin allergy (atopy).

Short-term or mild skin allergies can be treated with antihistamines (not very effective) and/or corticosteroids, just as with people who need help with allergies that flare-up. A judicious use of a drug such as prednisone (a corticosteroid) is highly effective and generally safe as long as it is used for a short period of time.

Unfortunately, allergies often get worse with age. The young dog that needed to take a steroid for only two weeks out of the year may begin to itch for several months out of the year, and then steroids are not a great option anymore.

Skin testing is the gold standard for determining what your dog is allergic to. This is generally done by a veterinary dermatologist. Blood tests for allergies are also available. These may not be as accurate but can be very valuable and do not require a referral to a dermatologist. If your dog needs more than occasional steroids or antihistamines to control itching, hyposensitizing with allergy injections can help about 75% of allergic dogs. You need to be willing to invest a bit in the diagnosis and treatment, and you need to be willing to give the injections. It can take many months for the dog to improve.

Desensitization works better if begun earlier rather than later. Talk to your veterinarian if you have treated your dog for seasonal allergies multiple times.

But I Changed His Food, and He’s Still Scratching

Food allergies are less common than inhalant allergies but are a serious cause of chronic itching. A few basic facts can help you toward a diagnosis of food allergy so that you can stop wasting your money on buying 30 different kinds of dog food.

If a dog has a spring allergy, once the season passes, so should the itching. If he is allergic to something he is eating, he should itch until the food is eliminated. Typically, a food-allergic dog should be itchy all the time.

So when a dog comes in to me in January and the owner says he has been scratching for a year or more, I think less about inhalant allergies and more about food. However, if an atopic dog began scratching in April and the owners didn’t do anything about it, that poor dog may still be scratching in January. A good history is very important.

I Want to Test My Dog for Food Allergies

There is no, repeat, NO reliable blood test for food allergies. If you had “allergy testing” done and someone told you your dog is allergic to corn or chicken based on a blood test, don’t believe it. The only way to determine a food allergy is to put your dog on a hypoallergenic diet for a minimum of two to three months. If Mitch stops the itch on a limited-ingredient diet, then you’re on to something. If there is no reduction in itching, food is probably not the culprit.

Ten times a week I hear, “But the lamb and rice diet didn’t help.” Or, “He’s been on a grain-free diet, and he’s still itchy.” Okay. Let’s get to the bottom of this.

What does a hypoallergenic diet or limited-ingredient diet mean? It means you are using a diet that, let’s hope, contains novel ingredients your dog has never been exposed to. This means the diet should be limited to a new protein, a new grain, and nothing else. That’s why fish and sweet potato is a good limited-ingredient diet to try, for example.

Most dogs have not been fed whitefish and sweet potato. But if a dog had been raised on a fish farm or dug up sweet potatoes for a living, then this is not a novel diet to try on this dog!

Back in the day, when diagnosing food allergies was in its infancy, veterinarians tried to develop a diet made up of novel ingredients that owners could try on their own. Dog food never contained lamb and rice back then. So we had the owners homecook lamb and rice and feed it exclusively for eight to 12 weeks.

This is why “lamb and rice” diets became so popular. But the dog food industry misled the public, marketing these diets as “good for skin” and “veterinary recommended.”

Veterinarians had not been recommending lamb and rice because of its skin benefits; we were trying to diagnose food allergy. These commercial lamb and rice diets were neither “limited-ingredient” nor did they offer any special skin benefits. But consumers began buying them to solve their dog’s undiagnosed “skin problem.” The pet food industry represented lamb and rice as a doggy version of Botox.

Now the pet food industry is turning out diets composed of international buffet items. It’s getting harder and harder to find a diet that your food-allergic dog has never been exposed to. There are now hydrolyzed protein diets, true limited-ingredient diets and homecooked recipes available through your veterinarian that can be helpful in diagnosing food allergy. “Grain-free” is not a hypoallergenic diet.

No Fleas, No Food, Now What?

So if the fleas are gone and the strictly-adhered-to food trials didn’t help, we’re back to inhalant allergies as the most common cause of chronic or seasonal itching. (This  article does not address the other, less common causes of pruritis, such as other skin parasites, primary seborrheas, autoimmune disease, recurrent bacterial pyoderma… and the list goes on.)

Don’t let your dog scratch for too long before seeking veterinary help. The longer dogs scratch without medical help, the harder it will be to stop the itching. Remember, allergies don’t usually begin until your dog is a few years old, but they get worse with age. Each time your dog is exposed to an allergen, the response is more severe.

How do I know what my dog is allergic to?

Skin test or blood test. Talk to your vet about whether this is necessary, and discuss what to expect when you get the results.

Can I limit my dog’s exposure?

Yes and no. You can bathe your dog once a week and keep him inside and not let him roll on freshly cut grass and keep him in air conditioning. You can try to protect him, like Seinfeld’s Bubble Boy, but he has to live and breathe and pee and poop, let’s hope outside. Think about when there’s a high pollen count advisory for people with allergies. Staying inside helps, but you still have to breathe and open a door once in a while.

What are my treatment options again?

If your dog has mild scratching because of allergies, your veterinarian may prescribe antihistamines, corticosteroids, fatty acid supplements and shampoos, to name a few. If your dog has been skin tested or you have sent out blood samples to a special allergy laboratory and the dog is diagnosed with allergies, you will begin giving allergy injections.

Unfortunately, there are no easy answers, and an allergic dog may need treatment for the rest of its life. Some of America’s favorite breeds are over-represented in this category,  including Golden Retrievers, Labs, westies, to name a few. But any dog can develop allergies, including mutts.

Continual itching is obviously annoying and harmful for your dog, but many clients don’t bring the dog in until they themselves are at their wits’ end. “The dog kept me up all night scratching!” is a common complaint. But what about the poor dog who may have been scratching to a lesser degree for the past month?

Dogs can’t help themselves. They’re like little kids. I was a little kid once… with chicken pox. A 3-year-old wants to scratch at those lesions until the itching stops. They’re unaware of the consequences, just like your dog. I remember my grandmother covering me from head to toe in calamine lotion and wrapping my hands in socks. I still managed to do a little damage. “See that scar on your forehead,” my grandmother would say to me for the rest of her life. “You wouldn’t listen. YOU KEPT SCRATCHING.”

Your dog needs your help to get to the bottom of the itch. Sooner rather than later. Real help. Spraying bitter apple on the problem or using home remedies might be as helpful as buckets of calamine lotion. No help at all. (In fact, calamine lotion may be toxic to your dog.) Putting socks on your dog’s back feet to stop the damage may last as long as the socks on my own little paws — not too long.

So don’t keep covering your itchy dog in Vaseline and corn starch and baking powder and eye of newt and dragon’s blood, particularly if these things are not working. Get that dog some help so everyone can have a nice sleep!

Welcome spring with the sounds of birds cooing. Not your dog biting and itching and thumping.

Photos, from top to bottom: TheGiantVermin/Flickr, apes_abroad/Flickr, Shutterstock

Dr. Debora Lichtenberg, VMD

View posts by Dr. Debora Lichtenberg, VMD
Dr. Debora Lichtenberg, VMD, is a small animal and exotics veterinarian who has split her time between a veterinary practice in Pelham, Massachusetts, and her studio in New York City. Dr. Lichtenberg is a graduate of the University of Pennsylvania School of Veterinary Medicine with 30 years of experience. Her special interests are soft tissue surgery and oncology.


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