Allergies in Dogs: Symptoms and Treatment

Dog Allergies

The information in this article was reviewed and approved by registered veterinary nurse, Beth Walker

Animed Veterinary Nurse, Beth Walker

Just like us, dogs can experience allergic reactions. Allergies are caused by the immune system mistakenly responding to a substance as if it were a threat. Usually, the immune system does a good job of protecting the body from threats like viruses and bacteria, but allergies occur when a dog’s immune system reacts unnecessarily. Lots of things can act as allergens to dogs, with common examples including specific foods, external parasites, and other environmental factors.

Spotting Dog Allergy Symptoms

One of the most common and obvious signs of allergies in dogs are skin problems. Itchy, irritated, red or scabby skin, as well as continuous scratching or biting of the body, are all signs that a dog is allergic to something nearby.

Other allergy symptoms may include:

  • Coughing, sneezing or wheezing
  • Discharge from the eyes or nose
  • Digestive upset such as vomiting, diarrhoea or loose stools

Diagnosing Allergies in Dogs

If you notice any of the symptoms discussed above, it’s crucial to take your dog to the vet so that you can work out what the allergen is. It can be a lengthy and difficult process to pin down what exactly a dog is allergic to, particularly as the symptoms are usually very similar to a wide range of other skin issues.

In terms of actual diagnostic tests for allergies in dogs, there are only two effective ones, both of which can be very expensive. We’ll come to those later. Before considering those, there are several steps we can take that may help us figure out an allergy:

Step 1: Take a thorough history of the dog and address any lifestyle factors

Your vet will ask you lots of questions about your dog to help identify any changes that might have taken place around the time the symptoms started.

If the symptoms started after your dog changed food, your vet might simply suggest changing the food back to what it was before. If this solves the problem, it would not usually be necessary to undertake a food allergy profile.

Asking questions about your dog’s lifestyle also allows your vet to find out if they’re receiving regular enough flea treatment. If they’re not, applying a flea treatment (or switching to a different one) is a simple way to rule out flea allergies being the cause.

Other parasites can also be ruled out through hair plucks, tape strips, wet paper tests, and skin scrapes. These tests all look for anything that may be causing itchiness.

Step 2: Attempt to break the ‘itch cycle’

A lot of itchy dogs will end up with skin infections from where they’ve scratched so much that they’ve caused trauma and damage to the skin. These infections will in turn cause more itching and a cycle ensues.

Treating the skin with the appropriate medication to help it get back to a healthy ‘normal’ can sometimes be enough to break the cycle of itching and cure symptoms.

Step 3: Conduct a food elimination trial

If the symptoms persist after these steps, your vet may recommend a food elimination trial.

Food elimination trials involve feeding your dog a specific diet recommended by your vet and nothing else for a fixed amount of time – usually around 6-8 weeks. If symptoms improve during this time, the dog’s old food (or a specific ingredient if a particular one is suspected) is then gradually reintroduced to check if symptoms reappear. If they do, your vet will be able to confirm a food allergy.

These trials are very inexpensive compared to the cost of full investigations, so they are well worth the time and effort if you’re able to commit to them.

Step 4: Diagnostic tests

After a food elimination trial, if you’re still unable to pinpoint the cause of your pet’s symptoms, your vet may recommend you go ahead with allergy diagnostic tests.

Despite some companies offering allergy tests that involve sending them samples or saliva or hair to be analysed, these have been shown to be very inaccurate and should not be used. In fact, there are only two tests for diagnosing allergies in dogs.

  1. Allergy blood test – Also known as a radioallergosorbent test (RAST). A blood sample is sent to a lab to test against allergens, and you receive a complex list of anything your dog is sensitive to. This can include foods, plants and more.
  2. Allergy skin test – Also known as intradermal skin testing (IDST). This is where a small amount of the potential allergen is injected into the dog’s skin and the area is observed for redness and swelling, which will confirm an allergy to that substance. This test is carried out under sedation, and the fur is clipped. The dog can’t be receiving any allergy medication when this test is carried out.

Once your vet is able to confirm whether your dog is allergic to fleas, food or something else in the environment, they will be able to recommend an appropriate treatment plan.

Flea Allergies in Dogs

Flea saliva is by far the most common insect allergen in dogs, causing flea allergy dermatitis. When a flea bites a dog, they inject their saliva, triggering an allergic response. Dogs that suffer from this allergy will react by itching, biting, scratching and may even remove large amounts of fur from their body.

Treatment for Flea Allergies in Dogs

Flea allergies can be easily treated with year-round flea treatment for the affected dog as well as any other pets in the household.

Getting rid of fleas requires a 360° approach, particularly if your home is already infested. As well as treating your pet, you’ll also need to deep clean carpets, bedding and other soft furnishings in the home, and apply household flea sprays.

Food Allergies in Dogs

Food allergies, nutrient intolerances or Adverse Food Reactions (AFR) are another cause of allergic reactions in dogs. Dogs can develop food allergies for almost any protein or carbohydrate component of food, but it most often develops in response to proteins. The most common allergenic protein for dogs is beef, followed by dairy and chicken. Other common allergens include lamb, wheat gluten and soy.

Most pet foods contain ‘intact’ or whole proteins which vary a lot in size. Non-allergic pets will be able to tolerate the larger protein molecules without any issues, but an allergic dog’s immune system will mistake the large dietary protein for a potential allergen, responding by triggering an allergic reaction. This results in skin problems and other uncomfortable symptoms for the dog.

Treatment for Food Allergies in Dogs

If you have been able to work out the specific ingredient that causes an allergic reaction in your dog, you can simply choose pet foods that don’t contain that ingredient. Always follow your vet’s advice when changing diets.

Hill’s offer a range of special Food Sensitivities diets for dogs with food allergies that contain hydrolysed protein. Hydrolysing a protein is where the molecules are cut into pieces so small that the immune system doesn’t recognise them as a threat. This way, your dog’s nutritional needs are still met without causing their immune system to trigger an allergic reaction.

Environmental or Atopic Dermatitis

If parasites and food allergies have been ruled out, it’s likely that your dog is allergic to something in the environment.

Atopy (also referred to as skin allergies) is the genetic tendency to develop allergies to a wide range of environmental factors. These may include plants, pollens, mould spores, dust mites, shed skin cells, as well as insects. The skin barrier doesn’t function as well as it should, allowing potential allergens to pass through the skin banner where they can trigger a reaction from the immune system.

Atopy is an inherited condition and some breeds, like terriers, are affected more than others. It causes inflammation that leads to redness of the skin, rashes, ear inflammation and recurrent infections.

Treatment for Environmental Triggers

It can be difficult to avoid environmental triggers altogether, but there are ways to minimise exposure. If your dog is allergic to dust mites for example, it is recommended that you clean your dog’s bedding at least once a week and vacuum regularly. This will help to limit their exposure to dust. If your dog has a pollen allergy, air purifiers can help to keep the home free from allergens.

Regularly bathing your dog can help to remove allergens in and on the coat to stop them being absorbed through the skin. It’s best to use prescription or hypoallergenic shampoos that are designed to soothe itchy and inflamed skin, and avoid bathing your dog too frequently. Over-bathing can dry out their already-irritated skin.

However, it’s nearly impossible to avoid environmental allergens altogether, so in some cases, medication such as steroids will be required to control your dog’s immune response.

Allergen-specific immunotherapy (also known as hyposensitisation or desensitisation treatment) is another form of treatment, which involves gradually building up your pet’s tolerance to the specific allergens that are causing their allergic reactions. Small amounts of the allergens are injected under the skin, usually at the scruff of the neck, over a period of time. This continuous low level exposure to the allergens allows your dog to build up tolerance to the allergens so they no longer produce an allergic response.

Your vet may also recommend a specialist diet, such as Hill’s Prescription Diet Derm Complete. This is specifically designed to support dogs with environmental and food allergies, and contains limited ingredients with just one intact novel animal protein. It also contains high levels of essential fatty acids to support skin barrier function, and bioactives and phytonutrients to support a healthy immune response.

How Common are Allergies in Dogs?

All dogs could potentially experience an allergic reaction, and unfortunately it is fairly common in all breeds and backgrounds. However, some breeds are thought to be more prone than others. With regard to food allergies, more susceptible breeds include:

  • Labrador Retrievers
  • West Highland White Terriers
  • Cocker Spaniels

The risk of developing environmental allergies is thought to be higher in the following breeds:

  • Chinese Shar-Peis
  • Wirehaired Fox Terriers
  • Golden Retrievers
  • Dalmatians
  • Boxers
  • Boston Terriers
  • Labrador Retrievers
  • Lhasa Apsos
  • Scottish Terriers
  • Shih Tzus
  • West Highland White Terriers

Some allergies are thought to be inherited, so the likelihood of a puppy developing certain allergies is higher if their parents were allergic.

The onset of environmental allergies tends to be between 6 months and 3 years of age, whereas the age of onset is much more variable with food allergies, as is the intensity of symptoms.

Dog Food for Allergies

Your vet may recommend a special diet to support your dog with their allergies. As well as the ones already mentioned in this blog, Hill’s Science Plan Hypoallergenic dog food is another great range for dogs who suffer from allergies. There are small, medium and large breed versions available, and all are formulated with just two intact protein sources, which are high quality salmon and tuna. Gentle on the stomach, they’re perfect for dogs with sensitivities and they contain plenty of omega-3 and omega-6 fatty acids for healthy skin nourishment.

Hill’s also offer a range of hypoallergenic dog treats.

Wrapping Up

Allergies can cause a lot of discomfort for our pups, and it’s important to get to the bottom of what’s causing their symptoms as soon as possible. Food elimination trials and other tests are essential to helping your vet make a diagnosis, and then you’ll be able to discuss suitable treatments and ways to limit your dog’s exposure to the allergens.

Sometimes skin conditions are a result of something else rather than an allergy. Read our blog on dog skin conditions for more information about the different causes of skin problems in our canine companions.

Visit the Animed Direct website for our full range of skin and allergy products and to search our prescriptions A-Z.