Grass Allergy in Dogs: Symptoms, Causes and Treatment
- Dr Simon Want BVM&S CertVD MRCVS RCVS
- Jul 28
- 8 min read
Updated: Aug 13
Grass allergy is a type of allergic skin disease that affects dogs. Allergic skin disease is one of the most common conditions we see in dogs, in fact up to 20% of dogs are affected by allergic skin disease. This seems to be mirroring the increase we are seeing in people. It’s often the most popular breeds that are being affected, plus with a limited gene pool to breed from, the rate in dogs is very high.
It’s not just grass that dogs are allergic to, dogs can be allergic to foods, indoor allergens, such as house dust mites and pollens. They can be allergic to tree pollen, weed pollen, crop pollen and, of course, grass pollen.
In this article we’ll discuss:
Can Dogs Be Allergic To Grass?
Yes, dogs are very commonly allergic to grass. The condition that grass allergy causes is called ‘Atopic dermatitis’. Allergy to grass causes a hypersensitivity reaction resulting in an inappropriate response from the immune system. The immune system in normal individuals can screen out harmless allergens such as grass pollen but in allergic individuals our immune system behaves as if it is being attacked. The results are the symptoms we see in allergic dogs.
Why are Some Dogs Allergic to Grass?
We know that Atopic dermatitis (grass allergy) is a genetic disease. If you have an allergic parent or grandparent you have a high chance of being allergic. The same is true for dogs, as for people. Then we become allergic to what we are exposed to, so environmental factors are important.
Dogs that are allergic to grass will have been exposed to that particular grass pollen over time, it’s in:
their local environment
their garden
the fields around where they live and walk
Pollen floats on the air so it can travel. It lands on your dog’s fur and skin and this then elicits the allergic reaction to grass in dogs.
Canine Grass Allergy Symptoms and Signs
The symptoms of grass allergy in dogs are variable and not all dogs will exhibit every symptom. The number one symptom we see in dogs that are allergic to grass is itching. The results of this itch account for the symptoms we see. We can also see allergic conjunctivitis and sneezing, the same as hay fever in people.
Grass allergy symptoms in dogs include:
Rubbing or scratching the face or ears
Scratching the body
Licking the body, legs and feet
Rubbing the bottom
Ear infections and red ears with or without a discharge
Red or greasy skin on the paws
Red skin on the body
Skin infections - think grass rash on a dog’s belly - often due to a secondary bacteria or yeast infection due to the grass allergy
Runny eye - rubbing around the eyes - hair loss around the eyes
Rubbing or scratching the lips
Very occasionally diarrhoea/soft stools or vomiting - more common in food allergy but not impossible
What Does A Grass Allergy Look Like?
If your dog is experiencing a dog allergy, you may notice red skin on their body, runny eyes and red or greasy skin on their paws.
What Does A Grass Allergy Rash Look Like On A Dog's Belly?
An allergic reaction to grass can cause a rash on their belly. This will present as red skin, spots and itchiness. If you notice these symptoms speak to your vet or a veterinary dermatologist.
Veterinary Tests to Diagnose Grass Allergy in Dogs
The diagnosis of Atopic dermatitis (grass allergy) in dogs is made by excluding other causes of itchiness, mainly parasites and food allergy.
Your dog’s history can suggest if they have grass allergy as grass pollen is seasonal. A dog who is itchy between late spring and autumn is likely to have a grass allergy. Also, a dog who is itchy all year round but is worse in the spring and summer may have other allergies, which are worse during the grass pollen season.
It is important to recognise this as the tests vets have to diagnose and document grass allergy in dogs are not 100% reliable. This is why a veterinary dermatologist can be so useful to help navigate the diagnosis and treatment of dog grass allergy.
There are two types of test available to diagnose grass allergy in dogs.
The first type of test is usually only performed by veterinary dermatologists. It is called an intradermal skin test and most dogs are sedated to have this test performed. This is considered the ‘gold standard’ test. A small patch of fur is clipped on the lower side of one chest wall. Small quantities of test reagent are then injected into the skin, not under, and the test is read a few minutes later. The first two injections are our control injections. The first is histamine and this creates a larger red welt in the skin. The second is a non-reactive injection that creates a bleb in the skin. The rest are the allergens we are interested in, i.e. our grass pollens, weed pollens, tree pollens, house dust mites (little mites that live in our carpets, furniture and bedding), storage mites (these live in processed foods). Reactions to any of these are scored against the control injections.
The second type of test is much simpler and is a blood test. This test measures antibody levels to different allergens in the bloodstream. There are numerous on the market and some are superior to others. Antibodies can drop out of the blood and it is possible to miss a grass pollen allergy if you test out of season, such as in the middle of winter.
The best results use a combination of both tests which is why we use both tests at Advanced Veterinary Dermatology.
It should be noted that 90% of grass allergic dogs will give you a positive test but that leaves 10% who may have a grass allergy, but we cannot prove it on the tests currently available to veterinary medicine. We say that these dogs have ‘atopic-like dermatitis’. They fit the criteria but we cannot prove an antibody response.
Treatment Options for Grass Allergy in Dogs
The one treatment we have that can tackle the causes of grass allergy in dogs by redirecting the immune system is immunotherapy.
Immunotherapy requires a positive allergy test as we use the history and documented allergens to create a vaccine. These ‘allergy shots’ are injected under the skin. They are administered for life. 80% of dogs will respond from excellent, good to fair. 20% may not respond and the effects can take from 3 to 9 months up to 1 to 2 years to be seen.
Other treatments that target parts of the immune system responsible for allergy include tablets, oral solutions and injections.
These include:
Cytopoint® injections
Apoquel® tablets
Zenrelia® tablets
Ciclosporin A - Atopica®, Sporimune® and Cyclavance®
Steroids
Redonyl® - a naturally occurring lipid (fat) compound
Antihistamines
Other treatments:
Essential fatty acid supplements
Topical steroid sprays and creams
Topical antiseptics - shampoos, foams, sprays, gels
How to Stop my Dog From Itching After Being in Grass
If your dog has a known grass allergy then washing your dog after a walk can help wash off grass pollen. It can also help soothe the skin, especially if you use a soothing shampoo.
Walking your dog early in the morning can help but if the pollen count is high you can expect a worsening of symptoms, which may require increased levels of treatment.
Are There Any Safe Home Remedies To Relieve A Dog's Grass Allergy Itching?
There are not really any home remedies for dogs. It is against the law to medicate your dog with antihistamines unless under the supervision of a vet and some antihistamines can make your dog ill, including heart rhythm problems.
People often think dog grass allergy will respond the same way hay fever does, but grass allergy is not a histamine-based disease and so only 10% of dogs may get some limited benefit from antihistamines. This is why it is best to see your vet if you suspect your dog has a grass allergy.
“The only thing I could suggest is sunflower oil. The addition of this to your dog’s food can help skin barrier function, but on its own this is usually not enough.” Dr Simon Want BVM&S CertVD MRCVS
When Should I Take my Dog to a Vet for a Suspected Grass Allergy?
If your dog gets rashes or signs of itchiness at any time of year but especially during grass allergy season you should see your vet.
If the symptoms are not being satisfactorily controlled or wish to find out about other options of treatment available to a veterinary dermatologist, such as immunotherapy, then ask your vet to be referred to a skin vet with advanced dermatological training. You can also contact a veterinary dermatologist yourself and make an appointment.
Frequently Asked Questions
How Often Should I Wipe my Dog's Paws if They Have Grass Allergies?
Every time after a walk if they have a grass allergy and as often as directed by your vet. Some dogs are prone to secondary infections and you may be advised to use antiseptic wipes 2 to 3 times a week.
Are Certain Breeds of Dogs More Prone to Grass Allergies?
Yes, certain dog breeds are more prone to grass allergies, and it is all of the most popular breeds:
Labradors
Golden retrievers
Cocker & Springer spaniels
Cavalier King Charles spaniels
Cockerpoos/Cavapoos/Labradoodles/Goldendoodles
French bulldogs
English bulldogs
Miniature dachshunds
The list goes on!
Is it Possible for a Dog to Suddenly Develop a Grass Allergy Later in Life?
The most common period to start with grass allergy is between 1 and 3 years of age. However, we have seen it in dogs 6 months and younger and up to 7 years of age.
What’s The Effectiveness of Immunotherapy for Grass Allergies in Dogs?
There are many studies relating to immunotherapy and dogs, and many studies are ongoing.
The statistics I quote to clients are:
20% will respond so well they won’t need anything else
40% do really well with it and are better than without but will need other treatments to support immunotherapy
20% have a fair response - they may have fewer flare ups or be less itchy but the overall response may be harder to quantify
20% probably do not respond at all - this matches what we see with other anti-allergy drugs
Sources and References:
Rosser, E.J. (2004), Comparison of the results of intradermal testing and aeroallergen-specific IgE serum testing in dogs with warm weather, seasonal atopic dermatitis. Veterinary Dermatology, 15: 3-4.
Olivry, T., D. J. DeBoer, C. Favrot, H. A. Jackson, R. S. Mueller, T. Nuttall and P. Prélaud (2015). "Treatment of canine atopic dermatitis: 2015 updated guidelines from the International Committee on Allergic Diseases of Animals (ICADA)." BMC Vet Res 11: 210.
Forster S, Boegel A, Despa S, Trout C, King S. Comparative efficacy and safety of ilunocitinib and oclacitinib for the control of pruritus and associated skin lesions in dogs with atopic dermatitis. Vet Dermatol. 2025; 36: 165–176.
Tham, H.L. and Olivry, T. (2022), Determination of the efficacy rate and time-to-efficacy of subcutaneous immunotherapy in dogs with atopic dermatitis. Vet Dermatol, 33: 155-e44.
Fennis EE, van Damme CM, Schlotter YM, Sinke JD, Leistra MH, Bartels RT, et al. Efficacy of subcutaneous allergen immunotherapy in atopic dogs: A retrospective study of 664 cases. Vet Dermatol 2022; 33: 321–328.
Written and Approved by:
Dr Simon Want BVM&S CertVD MRCVS
RCVS Advanced Practitioner in Veterinary Dermatology
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