Chicken Allergy in Dogs? The Symptoms, and Why a Blood Test Won't Confirm It

It's late, your dog is up on the couch with you, and she's licking that paw again. The last round of ear drops ended a few weeks ago and her ears are red and gunky again, maybe her poop is softer than you'd like too, and none of it says "food" to you... but that's usually what a chicken allergy in dogs looks like. Kind of boring.

And you can't order the answer online.

The blood and saliva allergy kits sold there can't actually tell you if it's the chicken. Vets confirm it one way, with a strict food trial at home.

Can dogs be allergic to chicken?

Yes. Only beef and dairy set off more dogs than chicken. That's from 2016, when a group of vet dermatologists pooled 19 published studies (297 dogs, each with a confirmed food allergy) and counted up what every dog had reacted to, and beef was far out in front, with dairy just ahead of chicken.

Counting every food in the study, the percentages go over 100, because plenty of these dogs reacted to more than one food. Even the authors say to take the ranking loosely, since most dogs had only been tried on a handful of foods. So why chicken and beef? Mostly exposure, is what Tufts' vets think. They've been going into dog food for decades, those two, so far more dogs have had them.

A dog can do fine on chicken for years and only then start reacting. That's roughly how VCA describes these allergies, they usually build up after a long time on the same food, so "but she's always eaten this" doesn't clear chicken. Sorry.

Chicken allergy symptoms in dogs

Mostly it's an itch. She licks and chews at her feet, scratches, rubs her face along the rug... On a drawing of a dog you'd color in the ears, feet and belly first (the classic spots in Merck's vet manual), then her face and the skin around her rear, which AKC adds.

Check the calendar, too. Her food is the same in February as in August, so this itch usually is too, about as bad in one as in the other.

Ear infections turn up in roughly half of food-allergic dogs (AKC's number), and in some dogs nobody ever notices anything else. A skin infection or yeast that gets treated and keeps coming back is another hint.

And some dogs get it in the gut, with the itch or without: she throws up, she's gassy, her stool is loose, or she just has to go more than three times a day (Merck really lists that one). That's about 30% of food-allergic dogs, AKC says, and more often puppies.

Her age won't settle it. Signs mostly start between 1 and 4 years old, per Merck, but there are cases from under 6 months old up to 13 years.

Food allergy, environmental allergy or just fleas

Honestly, if she's itchy, don't bet on food. It's the less likely answer. A 2017 review found a median of 18% of itchy dogs were food-allergic, and what's "far more common", in Tufts' words, is fleas and environmental allergies. On the dog they can look nearly identical.

An environmental allergy is her immune system going off at pollen, dust mites, mold and things like that. Atopic dermatitis, your vet will write. It tends to begin between 6 months and 3 years old, and it often flares and fades with the seasons (not always), and a dog can have both kinds, which is the annoying one: you switch her food and it helps a lot, just not all the way. Food intolerance is something else. Not an allergy at all, the immune system isn't involved (think of the diarrhea after a fatty scrap). AKC's point is that the fix is usually no different. You change what she eats.

Fleas get dealt with first, almost every time, and it doesn't matter that you've never seen one on her. Your vet will want flea protection on her all year round. If a food trial could come next, ask for a topical or unflavored product, since flavored chewables can throw off the results (Merck mentions it).

How vets confirm a chicken allergy in dogs

With an elimination diet, and then a challenge. It's slow and it's annoying, and it's the only test that counts.

For roughly 8 to 12 weeks your dog eats one diet that your vet picks, and nothing else. No "who wants a treat?" for a while. Tufts' list of things to stop runs from treats to rawhides, dental chews, table food, supplements, flavored medications and even her toothpaste, and AKC adds pill pockets and flavored toys, and wants the other pets fed where she can't raid their bowls. Slip once and it can cost you weeks. Why so long? In a 2015 study of 209 dogs, 5 weeks on the diet picked out about 80% of the food-allergic ones and 8 weeks more than 90%, so the researchers called 5 weeks the bare minimum. Her stomach usually settles before her skin does (PetMD gives digestive signs a week or two, skin and ears as long as 8 weeks).

Once her skin is clearly better, you get to the step you'd rather skip. Chicken goes back in her bowl, on purpose. The itch can return in hours or days, and sometimes it needs 10 to 14 days (Merck's timing). If she flares on chicken and settles again once you take it away... there's your answer. Your vet might then bring other foods back one at a time, around two weeks apart.

Why blood, saliva and hair tests don't count

Because they find allergies in healthy dogs. And in things that aren't dogs. For a 2018 report, somebody took fur from stuffed animals, swapped the saliva for plain water, mailed it all to a hair and saliva test, and got back a list of allergies.

When Tufts' nutrition team looked at the research, healthy dogs often came out just as "allergic" as the allergic ones. In one study of 30 healthy dogs, 60% to 100% tested positive for at least one food, and in another the saliva test gave the healthy dogs more positives than the allergic dogs.

These tests are quick and the list looks tidy, but "chicken" on it may only be a lucky hit, and no chicken on it hasn't really cleared chicken.

In 2017 Olivry and Mueller reviewed the evidence and couldn't recommend a single one of these tests for diagnosing food allergy in dogs. The blood IgE tests came in anywhere from 58% to 87% accurate.

Where chicken hides in your dog's week

Say the kibble is beef or salmon now and the scratching hasn't stopped. Check everything else that ends up in her mouth, because chicken is in a lot of it:

• Treats, jerky, training bites etc.
• The dental chew, and some rawhide-style chews.
• Whatever gets poured over her dinner, chicken broth or a topper.
• Flavored medications, chewable supplements.
• Pill pockets, and the piece of rotisserie chicken her pill gets hidden in.
• Food with another protein on the label. A 2018 study of wet limited-ingredient foods turned up undeclared chicken in four cans, and the labels said turkey, rabbit and duck.

So turn the bag over and read it.

"Chicken meal", "chicken by-products" and "poultry" all count. Chicken fat is harder to call. Properly rendered, it has no intact protein left in it, says a nutritionist writing for Whole Dog Journal, which is how it ends up in some allergy diets. Ask your vet before you rely on it.

Our own soft chew is beef-flavored, with no chicken ingredient on the label. The label does name shellfish and soy as potential allergens, and since the chew is flavored, tell your vet about it before a food trial starts.

What to look for in dog food for chicken allergy

For the trial itself, walk past the pet store's limited-ingredient bags. Tufts says skip them and so does PetMD. A 2013 study checked 12 dry limited-ingredient foods against their labels, and only 2 matched. The other 10 had animal proteins that weren't listed, and cross-contact like that can be enough to keep her itching.

Your vet is more likely to bring up one of two diets.

One is hydrolyzed. The protein gets chopped into pieces so small that her immune system, ideally, doesn't recognize them, and Merck rates the extensively hydrolyzed kind as less likely to cause a reaction. Useful when you can't really say what she's eaten over the years, and who can? Some of them are hydrolyzed chicken, though, or even chicken feathers, so check with your vet that it suits a dog who reacts to chicken. The other is a novel protein diet, one protein and one carb that are both new to her (rabbit, say, or venison). You have to know everything she's ever eaten for that to work, and "novel" depends on the dog, as Tufts puts it.

Food allergy can't be cured. The treatment, VCA says, is keeping her off the food, plus medication for some dogs when a flare gets bad. During the trial your vet can also give her something for the itch, to keep her comfortable.

Can dogs be allergic to other things?

Plenty. These come up a lot:

• Grass. Yes, though it's the pollen she reacts to (an environmental allergy), and PetMD says she can have it without even being on the grass. Expect itchy paws, face, armpits and sides.
• Bees. Most stings leave a sore spot she licks at and some mild swelling. If her face or muzzle swells, or she vomits, has diarrhea or turns weak afterward, that's a vet right away.
• Peanut butter. Any protein she's eaten before is one she can react to, but xylitol is the bigger worry in that jar. Some nut butters are on the FDA's list of products that may contain it, and within an hour it can pull her blood sugar down.
• Cats. It happens, though PetMD says it isn't very common. Cat dander or saliva sets it off, and then it's itching, sneezing, watery eyes and ear infections.

If the itch keeps coming back, two things travel with allergies often enough to be worth reading about: how to stop your dog from licking her paws, and what a dog paw yeast infection looks like. After that it's a vet appointment and a couple of months of plain, boring dinners. She'll forgive you, and you'll finally know.

Photos don't show diagnosed cases.