How to help dog allergies

dog itching leg

Just like humans, dogs can also develop allergies. What is an allergy? It’s an exaggerated response from the immune system to a trigger (also known as an allergen). 

Dog allergies are complex, and there are many different types of allergies, but they can generally be split into three main categories: parasites (fleas), food and environmental.

To make things more confusing, dogs can have allergies to more than one of these categories. These categories tend to be linked to chronic (longer-term) allergies; there are also shorter-term allergic reactions, like contact allergies and anaphylactic shock. 

What are the common allergy-causing substances (allergens)?

The most common environmental triggers include pollen, mold spores, dust, and storage mites. The most common food triggers are chicken, dairy and beef.

Flea allergies are caused by a response to the flea saliva when it bites your dog. Contact allergies tend to result from substances like certain fabrics, washing powder and other cleaning products. 

Symptoms of allergies in dogs

Allergies are fairly common in dogs. Up to 10% of dogs in the UK have atopy (environmental allergies). Food allergies are less common but are still seen regularly. The signs of atopy usually start between 6 months and 3 years old, and they can be seasonal or all year round. Food allergies can start at any age. 

The symptoms of allergies tend to mostly affect the skin and ears. The most common sign is itching - also known as the medical term pruritus. Itching may present as scratching, licking, or biting excessively. Other signs include red skin, rashes, ear infections and hair loss. It’s not just the skin that is affected by allergies. 

Respiratory symptoms

Dogs may have gastrointestinal or respiratory signs too. These include vomiting, diarrhea, sneezing, a runny nose, and itchy eyes. In some cases, you might notice your dog is quieter and more lethargic than normal. 

Anaphylactic shock is life-threatening but fortunately, quite rare in dogs. It tends to be related to insect stings or bites. The symptoms of this include a swollen face, excessive drooling, vomiting, breathing difficulties and collapse. Dogs showing these symptoms need emergency vet treatment. 

Are certain breeds more likely to have allergies?

Certain dog breeds have a higher susceptibility to allergies compared to others.

  • Breeds including Labrador Retrievers, Golden Retrievers, Chinese Shar-Peis, English Springer Spaniels, Boxers, Hungarian Vizslas, Basset Hounds, Rhodesian Ridgebacks, West Highland White Terriers, Bull Terriers, French Bulldogs, and Bichon Frise’s have demonstrated are more likely to develop environmental allergies.
  • Breeds including Labradors, West Highland White Terriers, French Bulldogs, Cocker Spaniels, and Irish Setters are at a higher risk of food allergies.

Diagnosing allergies in dogs

The diagnosis of allergies is not easy, it can be time-consuming and frustrating. Often, it’s a case of ruling out other causes.

Vets need to do skin tests to rule out parasites like mange, and to determine what abnormalities are present on the surface of the skin (bacteria, fungal etc.). Blood and urine tests may also be needed. 

A diet trial is needed to rule out food allergies in most dogs showing signs of allergies. This involves using a novel protein or hydrolysed protein diet for at least 6-8 weeks to assess the response. 

There are allergy tests that can be done in practice, either blood tests or intradermal skin tests. Intradermal skin testing is considered the most reliable way to diagnose allergies among skin specialists. It involves injecting tiny amounts of allergens just under the skin to assess the reaction. 

Dog allergy treatment and prevention

The best way to treat allergies is to use a multi-modal approach. This involves dietary changes, supplements, topical products, good parasite control and, when needed, prescription anti-itch medication. 


Diet is an extremely important factor in managing allergies, even if food allergies have been ruled out. There are diets available that are specifically made to help support dogs with symptoms of allergies. They include high levels of fatty acids to help strengthen the skin barrier and a single novel protein.

Dogs with food allergies will initially be on a novel protein or hydrolysed diet. Many of these can be continued long-term, or it may be possible to trial other diets, depending on the symptoms. 

Topical products

Shampoos and mousses can help relieve dogs with mild skin infections, greasy or oily skin and irritated skin.

Regular ear cleaning with vet-recommended products can help reduce recurrent ear infections.


Supplements containing fatty acids can help support the skin barrier. These are usually given by mouth.

Probiotics can be useful for dogs with tummy upsets. 

Dogs suspected of having a flea allergy

Need strict regular, long-term vet-recommended flea control. 

All in-contact pets will also need to be kept up to date.

It may be recommended to use a household spray that gets rid of adult fleas, flea eggs and larvae. This is necessary if there is an infestation but can also be useful long-term. Some of these products also reduce dust mites. 

May also need short term anti-itch or antibiotic medication for any flare-ups or if they have allergies to other things too. 

How to help at home

  • Regularly clean your dog’s bedding, collar, and bowls
  • Dust and vacuum the house often and avoid sprays or perfumes in the house
  • Avoid smoking in the house
  • Brush your dog regularly and check for any abnormal areas of skin or hair loss

Prescription medications

Parasite control to protect against mange is only available on prescription.

Anti-itch medications are useful for moderate to severely itchy dogs to make them more comfortable and prevent self-trauma. These come in many different types and forms, including tablets, injections, and sprays. 

When to consult a vet

Our Joii vets help dogs with allergies every day, they can help recommend the best food, supplements, and topical products for your dog. They are available 24 hours a day for advice. 

When do you need to see a vet in practice?

  • Any dogs with frequent itching, where it’s not controlled with topical products and it’s interrupting their normal routine.
  • Any dogs with widespread areas of inflamed, scabby, or moist skin all over the body.
  • Any dogs that have suspected mange.
  • Any dogs with thick, swollen ears or ears that have yellow/green discharge. 

What to expect

If your dog has been diagnosed with flea, food, or environmental allergies, it unfortunately means long-term treatment. Regular vet checks - at least every 6 months - are essential to keep on top of the symptoms and avoid the development of secondary infections.

Allergies cannot be prevented or cured, but they can often be well managed so that dogs can live normal, happy lives.

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