Does my dog have allergies?

By HUB SmartCoverage Team on June 14th, 2023

Every dog scratches once and a while, but when they itch all the time there’s something else at work.

The first step with any itchy dog is to try and determine the cause. This involves looking at factors such as the dog’s age, breed, history, seasonality of symptoms, Dogs can be itchy – the medical term for this is pruritus - for many reasons.

In Ontario, allergies are one of the most common reasons. Canines can be allergic to 4 main things: food, things in the environment such as trees or dust, contact allergies such as fleas, shampoos, creams. If the allergies tend to get worse during certain times of the year, external parasites, biting insects, or environmental factors tend to be the more likely culprits.

Most allergies can emerge at any age and once there, they are often for life.

The Difference Between Allergies and Sensitivities

The terms “allergy” and “sensitivity” are loosely used but it is important to understand the difference. An allergy occurs when a reaction is triggered by the dog’s immune system. A sensitivity is a reaction triggered in the digestive system.

According to the American Kennel Club, the most common signs of allergies include:

Excessively licking their feet and paws
Rubbing and scratching their face
Scratching and itching their armpit regions
Rubbing and scooting their bums
Itchy, runny eyes
Red, inflamed skin
Chronic ear infections
Sneezing
Vomiting/Diarrhea
Hives
Swelling of face, ears, lips, eyelids or earflaps

The most common causes of itchiness

Fleas Flea allergy dermatitis is typically the easiest allergy to diagnose since it is found by identifying fleas on your dog’s body. This is the easiest to treat by applying a product that kills fleas before they can bite. It’s also a reason to keep your fur-friend treated year-round.
Food allergies These are typically seen in dogs less than 6-8 months of age and will have a non-seasonal pattern. Some dogs with a food allergy will also have concurrent gastrointestinal symptoms such as diarrhea or vomiting. The most common allergy food ingredients include beef, dairy products, chicken, pork and lamb. These types of allergies are not all that common in dogs - only about 5 per cent are affected.
Seasonal allergies Dogs with seasonal allergies may become itchier during autumn when pollens are high, or in spring when grass or tree pollens are present. Seasonal allergies can also be called atopy or allergic dermatitis, which is an inherited condition that develops because of a complex interaction between genetic and environmental factors. In dogs with seasonal allergies (atopy), the itchiness is usually noticed after exposure to moulds or pollens. Approximately 1 in 10 dogs in this part of the world have environmental allergies.
Skin infections These infections can be bacterial, fungal (yeast), or both. Dogs with skin infections will typically have concurrent hair loss, redness and a bad odour. The most common areas for infection are the feet (particularly between the toes), armpits and groin region. Most skin infections in dogs are secondary to other conditions, such as allergies and management of those conditions is important.

What can you do at home

Consult your veterinarian for a proper diagnosis and they can help formulate a successful treatment plan. However, there are some things you can safely do at home. If you suspect your dog has a food allergy, avoiding the most common ingredients that cause allergies is a start. Remember that this also includes treats and snacks!

Fish oil supplementation (omega fatty acids) can be beneficial in dogs with seasonal allergies as they provide a natural anti-inflammatory effect. Although omega fatty acids work best when combined with additional therapies, you can safely try this at home.

Antihistamines have been shown to be somewhat beneficial in the treatment of pruritus in dogs, but they are unlikely to help with acute flare-ups. Consult with your vet about their use. Benadryl (diphenhydramine) is a safe antihistamine to use in dogs and most veterinarians recommend 2 mg/kg every 8-24 hours as needed. But they should be used with caution in dogs that have known sensitivities or have respiratory diseases such as asthma, liver disease, and seizure disorders. Avoid antihistamines that contain pseudoephedrine as this is extremely toxic to dogs.

Regular bathing of dogs with seasonal allergies with a regular, aloe and oatmeal-based shampoo every week can help since it reduces the pollens and contaminants from your dog’s fur. Avoid using fragrant shampoos as they can be irritating to your fur friend’s skin.

Treatment and your vet

Diagnosing allergies is often complicated. The first thing your veterinarian may choose to do is rule out any other condition that could be causing your dog’s symptoms. They may also propose allergy testing to try and determine the cause of the allergen that is causing the reaction. There’s a wide range of treatments such as allergy shots or medications.

Food allergies are often diagnosed using an elimination diet. A food trial consists of feeding a dog a novel (i.e. one) source of protein and carbohydrate for 12 weeks.

Good communication with your vet about your dog’s allergies is essential. Results will vary, but the dogs that are treated consistently have a greater chance of success. Never discontinue medications or treatments without first discussing it with your vet.