There are several common allergies in dogs that can make life difficult for both you and your pup. An allergy is a state of overactivity of the immune system and most allergens are the result of proteins found in plants, insects, other animals, and food.
Clinical signs of dog allergies include itchy skin, stomach problems, runny eyes, inflamed skin, and ear infections, all of which can be very uncomfortable for your canine companion. Most allergies appear in dogs over the age of six months and it can take a process of trial and error to figure out exactly what it is that’s causing your dog’s symptoms.
Getting to the bottom of your pup’s allergy takes time and patience, and it also has its moments of being frustrating and expensive. It can be difficult to know how to help a dog with allergies, so Dr. Joanna Woodnutt is here to talk us through the most common allergies in dogs and how best to tackle each one.
What is the most common allergy in dogs?
"The most common food allergens in dogs are chicken, beef, and dairy products," explains Dr. Godfrey. "However, allergies to pollens and fleas are also very common.
Not every dog with symptoms of allergies has tests performed to find out what they are allergic to. This is because some of the tests can be unreliable, costly, and time-consuming, and they may not change the treatment or what you are able to do about it.
For example, you can’t control your dog’s exposure to pollen, and even with excellent flea control, you can’t stop the occasional flea from jumping onto your dog. Therefore, without testing, it’s not necessarily easy to say reliably which allergies are most common."
1. Allergies to storage mites and house dust mites in dogs
Nobody likes to think of the mites living in their homes, but the truth is that all homes have these microscopic creatures. The percentage of dogs that are allergic to mites varies between studies, but around 60-80% of allergic dogs appear to be allergic to mites.
House dust mites live in the carpet and soft furnishings, where they feed off shed skin cells. Storage mites like to live in dried goods in storage – hence the name. They once would have infested grain stores, but in our homes can more usually be found in old bags of flour or at the bottom of a bag of dog food.
Some studies have shown that over 80% of allergic dogs test positive for mite allergy, so this is as good a place as any to start your search.
What you and your vet can do to help mite allergies in dogs
Although mites are everywhere, there’s lots you can do to help keep on top of them. Storage mites can be reduced by buying smaller bags of dog food or freezing dog food in smaller portions so that the mites don’t get access to a whole bag of food.
Some flea sprays will also be effective against mites, including house dust mites – your vet can tell you which products are legal and licensed in your area, or getting a professional exterminator in might be suitable. Hypoallergenic dog bedding will reduce the places the mites can contact your dog, too – as will regular washing at a high temperature.
Don’t forget there’s a range of medications your vet can give you to help. Once a mite allergy has been diagnosed, your vet can have ‘vaccinations’ made against the allergens – injecting small amounts of the allergen under your dog’s skin can teach their body not to react to it. Around 60% of cases are helped with this method. Drugs may also be necessary to get on top of the allergy, especially as mite allergies usually affect dogs all year round.
2. Allergies to tree, weed and grass pollen in dogs
Can dogs be allergic to grass? Absolutely! Hay fever sufferers will know that pollen allergies are difficult to live with. Dogs can be allergic to tree pollen, weed pollen or grass pollen, or a mixture of all three. Again, the percentages of dogs with this sort of allergy vary from study to study. Birch and elm are common allergens, with over 50% of allergic dogs reacting.
The most common grass pollen allergy is to Timothy grass, and the most common weed allergy is to English Plantain. Mold allergies are also common. To make matters worse, many dogs are allergic to more than one weed, grass or tree – in fact, sometimes they’re allergic to almost everything tested.
In addition, they can gain new allergies as they age, which is a common reason for their symptoms to reappear after being well controlled. Pollen allergies tend to be seasonal to a degree – your dog might suffer in Spring, Summer or Autumn, depending on what they react to. It’s rare for environmental allergens to affect a dog all year round without a break.
For more on grass allergies and how to manage them, 'I didn’t know dogs could have allergies until I found out mine was allergic to grass - here’s how we cope' has some great advice
What you and your vet can do about environmental allergens
Dealing with environmental allergies in dogs is tricky. As with mite allergens, your veterinarian can order a specialized immunotherapy ‘vaccination’, which teaches your dog’s body not to react. For one-third of cases, this works really well, and for a third of cases, it doesn’t work at all. For the final third, it works to an extent, but some other medications may be needed at peak pollen season.
There aren’t many things you can do to help your dog with environmental allergies. As hay fever sufferers know, avoiding pollen is almost impossible. However, there are some good tips over in our feature on coping with allergic pets.
3. Flea allergies and flea hypersensitivity in dogs
In cats, flea allergies are more common than any other allergy type. In dogs, we think that flea bite allergy is slightly less common, although it’s hard to tell. Many dogs are allergic to fleas as well as to environmental allergens such as pollen and mites.
Flea bite hypersensitivity (also known as flea allergic dermatitis) occurs when dogs are sensitized to the protein in flea saliva. Dogs don’t need to have fleas for their allergy to flare – contact with a single flea is enough to cause a severe itch.
What you and your vet can do to help flea allergy in dogs
Flea allergies are generally easy to keep under control. Your dog will need high-efficacy flea treatment and it needs to be applied on time, regularly and without gaps in cover. Products that repel fleas as well as kill them are sometimes more effective, as many flea treatments need dogs to be bitten to work properly.
Don’t forget to treat the other animals in the house, too – if your cat brings fleas in from outside, your dog is going to keep on reacting. You can learn more about the different treatment options in our buying guide to the best flea treatment for dogs.
4. Food allergies
When a dog starts to show signs of an allergy, many people immediately assume they are allergic to best dry dog food or wet food. But only around one in ten allergies is to something in the food, with the most common food allergen thought to be beef. Chicken protein also commonly causes allergic reactions in dogs.
Grain is often blamed for allergic reactions by dog owners, but grain allergies are thought to make up fewer than one in ten food allergies. So, that's fewer than one in 100 allergic dogs that have grain allergies. Dogs can become allergic to food even if they have been on that type of food for their whole lives. Once symptoms start, they tend not to wax and wane, and they’re never seasonal.
What you and your vet can do to help food allergies in dogs
Food vs environment allergies differ in that food allergies are simple to treat – you simply stop feeding the protein that your dog is allergic to. They’re also theoretically simple to diagnose – you feed them a diet without allergens for eight weeks, and if the symptoms go away, you know your dog has food allergies. You can read more in our article on common food allergies in dogs and cats.
How do I know what my dog is allergic to?
"It’s not always easy to determine what your dog is allergic to," explains Dr. Godfrey. "You might notice that they react very obviously when you change your washing powder or home fragrance. Or you might spot their symptoms straight after you change their dog food or offer them human food they haven’t had before.
However, there isn’t always a clear pattern or cause. In these situations, a vet can take a blood sample to screen your dog for allergies. However, these tests can be costly and aren’t always reliable."
You can find out more about food-specific testing in our guide to dog food allergy tests: do they work and are they worth it?
How do you treat dog allergies?
"If your dog has a known food allergy, it’s easy enough to avoid that. If you want to exclude food allergens as a cause for your dog’s symptoms, you could try feeding them an ‘elimination diet’ for 8 weeks," Dr. Godfrey suggests.
"During this time, feed them food containing ingredients they’ve never eaten before. Ideally, this would be a specific hypoallergenic diet, where the ingredients have been treated with hydrolysis to make sure your dog’s immune system doesn’t recognize them.
If during the elimination diet, their symptoms resolve or improve, then putting them back on their normal diet makes their symptoms return, they likely have a food allergy, and feeding them a hypoallergenic diet long-term will help.
Among the treatments available to manage allergy symptoms, there are various anti-itch and anti-allergy tablets and injections. Your vet can recommend one that suits you and your dog best."
If you think your dog might be allergic, talk to your vet about their symptoms and whether you should be testing for allergies. The most common allergies in dogs are listed here, but there are all sorts of other things your dog could be allergic to, from feathers to newsprint.
After graduating as a veterinarian from the University of Nottingham, Dr Joanna Woodnutt went on to practice companion animal medicine in the Midlands, UK. Dr Woodnutt is specifically interested in consulting and helping her clients understand their pets better, whether it’s around medical problems such as dermatology, behavior, and nutrition.
Dr Hannah Godfrey studied Veterinary Medicine at the Royal Veterinary College London. After graduating in 2011, Dr Godfrey went on to become a veterinary surgeon, conducting surgery consultations on a range of animals at a small independent practice in Cardiff, South Wales, UK. Dr Godfrey has a strong interest in soft tissue surgery. When she’s not helping animals back on their feet, Dr Godfrey writes a number of veterinary and animal-focused articles.
