Does your dog seem overly itchy, or scratch or lick a lot? If the answer to any of these questions is yes, then there is a high possibility that your dog may be suffering from an allergy.
Allergies in dogs are almost as common as they are in humans, although far fewer people are aware of this. In fact, it is estimated that nearly 20% of all dogs suffer from allergies – a statistic that may surprise you.
Again, similarly to the allergies that we suffer, allergies in dogs can be itchy, irritating, uncomfortable, and sometimes very painful. As if that wasn’t bad enough, excessive scratching and licking can cause secondary infections, which in many cases, make the original symptoms even worse. In the worst affected areas, the dog can suffer from hair loss, causing so-called ‘hot spots’ to appear in their coat.
Here, we will explain the different types of allergies in dogs, the symptoms of an allergic reaction, and the best ways to treat a dog suffering from allergies. We will also talk you through how your dog can be diagnosed with an allergy, and explain which breeds of dog are the most prone to suffering from skin conditions.

What Causes Allergies in Dogs?

In all except the most extreme allergies, it takes more than one exposure to the allergenic substance to produce an allergic reaction. White blood cells in the body build up a memory of the allergens, and the more contact that the dog makes with the allergenic substance, the more their body will release histamines and the itchier they will become.
Unfortunately, as with all allergies, there is no cure – but they can be managed.
There are three types of allergies, and we will explore each in greater detail below:

• Atopy (also known as atopic dermatitis)
• Flea allergy dermatitis
• Food allergies

Atopic Dermatitis

Atopic dermatitis is an environmental allergic reaction to certain substances like pollen, mould, dust mites, or even animal dander (skin and hair fragments). In humans, it is more commonly known as hay fever.
Some atopic allergies may start out as seasonal, but as they are progressive, they are likely to worsen and cause your dog to become itchy all year round. Similarly, allergies to dust mites are also very common, meaning that the symptoms will persist year round.
Typically, the symptoms of atopic dermatitis will start when your dog is between 1-3 years old, although the signs have been known to occur from as early as 4 months up to 7 years of age.
What Causes it?
Dogs can come into contact with the allergenic substance either through inhalation or by direct contact. As a result, depending on the presence of the particular allergen, these allergies can be seasonal or all year round.
In most cases of atopic dermatitis, the allergens penetrate microscopically directly through the skin which triggers the itch response. At times when there is a higher concentration of the allergenic substance (such as pollen in the air), the dog’s body will release excess histamine which triggers the symptoms.
What are the Symptoms?
As atopic allergies result in itchy skin, the most common symptoms of atopy in dogs are scratching, licking and chewing affected areas. The worst affected areas are usually their paws, armpits, face, ears, and undercarriage.
If the itching and licking are allowed to continue, you will soon start to see redness in these areas. The dog’s scratching and biting may make the symptoms worse and could cause bacterial infections in their ears and on their skin. As a result, if you suspect that your pooch may be suffering from an atopic allergy, it’s important to check their ears for signs of infection. The best way to do this is to gently pull back the ear flap and look inside for any redness or discharge.
How Can it Be Treated?
As is the case with all allergies, sadly, atopic dermatitis is a lifelong condition. However, although it can’t be cured, the following ways should help you manage your dog’s condition:

• Anti-itch therapy using drugs – these can include antihistamines, corticosteroids, antibiotics to treat infections, medicated shampoos, conditioners and skin lotions or creams. It’s important to note that if you are using drugs to manage your dog’s allergy, you should always consult your vet first and be mindful of any potential side effects
• Removing the source of the allergy – granted, this isn’t always possible, but where you can, try to remove the source of the allergy. Pollen can be carried up to 80km when airborne, and dust mites are everywhere, but you can take practical steps like removing allergenic plants from your garden and washing your dog’s paws to remove allergens after walks
• Collars, socks or t-shirts – special items of clothing like these can help to reduce trauma, reduce the risk of infection, and help when symptoms are only mild and occasional
• Hyposensitation therapy – through the use of allergy ‘vaccine’ shots, your dog will gradually become desensitised to the allergens. While the effectiveness of this method varies, 75% of pets have recognised some relief from this form of therapy
• Supplements – Biotin or omega-3 oils have a natural anti-inflammatory effect that will suppress itching and support coat health

Flea Allergy Dermatitis

Flea allergy dermatitis is the most common skin disease for pets.
Flea allergies in dogs usually develop before five years of age, but they have been known to occur at any age.
What Causes it?
While fleas are certainly not nice in any regard, the saliva from flea bites is the actual cause of the allergy. Adult fleas are the ones that bite, as they need to feed in order to survive. Once the adult flea has laid its eggs on the body of its host dog, it will fall off and the cycle will continue. However, it’s also worth mentioning that an adult flea can’t survive for long without their host pet.
What are the Symptoms?
As is the case with atopic dermatitis, the most obvious symptom of a dog flea allergy is severe scratching and itchiness, also known as pruritis. Symptoms of dog flea allergies are usually episodic although, for most pooches, it will get worse as they get older.
For the worst affected dogs, just one or two flea bites can cause an outbreak of pruritis, and symptoms may continue after the application of flea control depending on the individual dog.
Additional symptoms include hair loss, scabs or lesions on the dog’s skin (usually on the back half of their body) and in some cases, a condition named neurodermatitis (behavioural problems resulting from flea bite hypersensitivity).
How Can it Be Treated?
All dogs should have regular flea control treatment, but for dogs with flea allergies, this is an absolute must. There are plenty of flea control products out there, but you should always be sure to follow the instructions on the packaging and, if in doubt, consult your vet.

Food Allergies

Approximately 10% of allergy cases in dogs are food allergies.
Before we continue, it’s also worth noting that food allergies and food intolerances are not the same. A true food allergy causes the body to produce an immune system reaction and in the worst cases, it can be highly severe. Conversely, food intolerance is usually less serious and will likely only cause digestive issues.
What Causes it?
Many food allergies are genetic and will be triggered whenever the dog is exposed to that particular allergenic substance. Similarly, most dogs with food allergies are usually allergic to more than one thing.
Some of the most common food allergens in dogs include:

• Meat (beef, chicken, lamb, pork, rabbit)
• Fish
• Egg
• Dairy
• Wheat
• Soy

What are the Symptoms?
Different dogs will present different symptoms of a food allergy, which is why it’s always important to get your pooch checked over by a vet to confirm the cause of your dog’s allergy.
Some symptoms of food allergies in dogs include:

• Digestive and gastrointestinal problems
• Diarrhoea
• Itchiness
• Ear inflammation

Are All Dogs Prone to Allergies?

Generally, every dog is at risk of suffering an allergic reaction to an allergenic substance. However, some breeds are more susceptible than others, largely down to genetics which makes their skin more fragile and susceptible to allergens.
These dog breeds are generally more prone to suffering from skin allergies:

• West Highland White Terrier
• Irish Setter
• Shar-Pei
• Maltese
• Bulldog
• Spaniel
• Dalmatian
• Labrador
• Golden Retriever
• Staffordshire Bull Terrier

If your dog suffers from an allergy, we would advise against breeding it as this is often an inherited condition.

The Bottom Line

Allergies in dogs are much more common than many of us think, and the number of dogs that are suffering from allergens is increasing. Many different allergens can affect our dogs, and whilst you can’t cure allergies, you can manage them and help your furry friend live a comfortable and (almost) itch-free life.
We would always recommend consulting your vet or a specialist canine dermatologist if you suspect that your dog is suffering from an allergy, as they will be best placed to identify the type of allergy affecting your dog and determine the best course of treatment.