What Causes Allergies in Dogs?

What Causes Allergies in Dogs?

It would be nice and easy if the answer to this question was straightforward.

Vet bills would be a lot less expensive and dogs wouldn’t have to endure the suffering from allergies for as long as they do.

The problem is that there are many reasons why dogs develop allergies.

In broad terms, allergies in dogs can be categorized into groups. These groups are:

  1. Allergic Dermatitis (skin allergies resulting in itching).
  2. Dog Food Allergies (various symptoms which can also include skin allergies)
  3. Life-Threatening Dog Allergies (allergens causing anaphylactic shock)

Allergic Dermatitis is grouped into further sub-categories:

  1. Flea Allergy Dermatitis (specifically caused by fleas)
  2. Contact Dermatitis (skin allergies caused by coming into direct contact with various substances)
  3. Dog Food Allergies (specifically causing skin irritation)
  4. Environmental Allergies (typically caused by airborne allergens such as pollen and dust)

Dog food appears in both lists above because it can cause various symptoms and not only skin allergies.

Allergic dermatitis is the chief cause of the itching associated with allergies in dogs.

In this post I’ll be covering all the topics above in greater detail.

The more in-depth information that follows should be able to help you identify what is causing allergies in your own dogs.

Causes, Symptoms, and Treatment of Allergic Dermatitis in Dogs

As mentioned in my introduction, the main groups (and causes) of allergic dermatitis in dogs are:

  • Dog Allergy Dermatitis Caused by Fleas
  • Dog Allergy Dermatitis Caused by Your Dog Coming Into Direct Contact With An Allergen
  • Dog Allergy Dermatitis Caused by Dog Food
  • Dog Allergy Dermatitis Caused by Allergens in The Environment Such as Dust or Pollen

Symptoms Associated With Dog Allergy Dermatitis Caused by Fleas

Dog Allergy Dermatitis Caused by Fleas

Like all forms of dog allergy dermatitis, the main symptom is excessive itching.

It is believed that the bite from the flea is not the cause of the allergic reaction, but is rather the saliva of the flea that causes the problem.

Another point to note is that for a dog with a severe allergy to flea saliva, it only takes one bite from one single flea to cause a reaction in the dog.

That final point can create a huge problem in determining if your dog’s allergy was caused by a flea or not. After all, the one, solitary flea could bite your dog and then drop off your dog, which then leaves no evidence that the flea was ever there in the first place.

As odd as it sounds, it is more useful if your dog has quite a few fleas present, because then there is more visible evidence that they are the cause.

As you can see in the diagram, around thirty flea eggs are laid per day. The eggs hatch within two to five days.

With eggs being laid and hatched with such frequency and numbers, it can be appreciated that infestation can take place quite rapidly.

If your dog suffers from a flea allergy, then itching will be very commonplace.

In addition to the scratching, your dog may also suffer from sores and hair loss, and scabs may also become noticeable on your dogs’ skin.

One fairly unique sign of dog flea allergies is that fleas very frequently bite the rear end of your dog. The lower back above the tail and the tops of the rear legs are their favorite feeding grounds.

Itching and sores in this area of your dog can be a clear indication that fleas are at work.

For dogs who suffer more severe allergic reactions to fleas may however have itching and sores all over their body. So the rear-end itching theory won’t be applicable to every dog.

Tips for Identifying Dog Fleas

  • Buy a flea comb and run it through your dog’s fur. Fleas are tiny (around 1.5 mm in length), but they can still be seen when using a flea comb. If you normally wear reading glasses, then wear them for this task.
  • Fleas leave their feces on your dog. The feces look like small, black spots. A wipe with some white tissue will leave rusty-colored markings on the tissue.
  • Either of the tests above can typically confirm if fleas are the issue.

Treatment of Dog Allergy Dermatitis Caused by Fleas

Because dog flea allergies have been around for a long time, the treatments are easy to use and are readily available in just about all pet stores.

It is seldom that you’ll need to pay vet bills to rid your dog of fleas.

The two primary dog flea treatments are:

  • Liquid drops which are applied to the back of your dog’s neck.
  • Dog flea collars.

People often wonder why the dog’s neck is used for flea remedies when the fleas could be anywhere on the dog’s body.

The reason why the dog’s neck is used is because it’s the one place that the dog cannot lick.

The neck is chosen simply so that the treatment can stay in place without your dog licking it off.

The dog flea liquid and collars both work in the same way. They both distribute the flea-killing solution into your dog’s skin.

The fleas will bite the skin over time, and when they do, they digest the flea control chemical and are then killed off.

Because it takes time for every flea to bite the skin, don’t expect these flea treatments to work overnight. Use them as prescribed and expect a waiting period to see the results.

Also, flea treatment should not be a one-off process. If your dog has had fleas once, then it is likely that they’ll strike again.

Repeat flea treatments every few months to keep the fleas under control.

Causes, Symptoms, and Treatment of Allergic Contact Dermatitis in Dogs

Contact Dermatitis in Dogs

Contact dermatitis in dogs is caused by a dog coming into direct contact with an allergen, or simply touching something that has caused an irritation.

It’s a little like us humans being stung by stinging nettles. You wouldn’t particularly call that an allergy, but more of a skin irritation.

Yet the effects of both types of irritant are certainly going to cause some stinging, itching or some kind of rash appearing.

Since a dog could be allergic to, or irritated by, so may different substances he comes into direct contact with, the list of possible causes is almost endless.

The most common causes of contact dermatitis allergies in dogs.

  • Grass
  • Plants
  • Garden products such as Herbicides and Fertilizers
  • Cedar chippings (frequently called mulch)
  • Floor cleaners and floor polish
  • Carpets
  • Concrete
  • Metal
  • Rubber
  • Plastic
  • Food allergy
  • Insect and spider bites
  • Allergies to medications

There is probably no exhaustive list in existence because somewhere, there’ll be a dog allergic to something that is not included in any list.

What is immediately evident, however, is just how many different substances can cause contact dermatitis allergies in dogs.

Some of the items in the list can be very easily accepted as possible allergens, whereas some items appear so harmless that you can’t possibly imagine them causing any issues for your dog.

But please put any disbelief aside because dogs have been known to suffer allergic symptoms from all the items in the above list.

Symptoms of contact dermatitis allergies in dogs.

Because contact allergies are due to your dog coming into direct contact with an allergen, it is typically the exposed skin on your dog that is most affected.

Areas where there is little or no hair are the places where your dogs’ skin can come into direct contact with allergens.

Common areas include:

  • The belly
  • The chin
  • Between the toes
  • The scrotum and anal area

The bodily regions above are all places where hair is at a minimum, and, are areas that come into contact with objects close to the ground very frequently.

The physical symptoms for your dog can include:

  • Hives
  • Rashes
  • Lumps
  • Bumps
  • Swellings

The physical sensation for your dog will be itching. The itching can be moderate or it can be severe.

Treatment of contact dermatitis allergies in dogs.

The treatment of contact allergies in dogs primarily involves investigating what the actual allergen was.

This is when your vet will need to wear his Sherlock Holmes hat and do some investigating.

If the allergen is obvious because you saw your dog touching the allergen and then the symptoms followed. Then this is easily treated by preventing your dog going near the substance again.

For unknown allergens it literally takes multiple tests to try determine the source of the problem.

A typical test is the Patch Test which involves your vet sticking allergen-coated patches on to your dog’s skin for 48 hours. The patches are then removed to see if any of the patches caused a reaction in your dog.

A typical test is the Patch Test which involves your vet sticking allergen-coated patches on to your dog’s skin for 48 hours. The patches are then removed to see if any of the patches caused a reaction in your dog.

Your vet may also perform bacterial cultures and possibly skin biopsies to try determine the cause of the irritation.

You can probably see by this stage that the entire course of treatment is designed to determine the allergen.

This is the case because once the allergen has been discovered, then it is simply a matter of keeping those substances away from your dog.

If for example your vet discovered that your floor cleaning solution was the culprit, then it is very easy to clean your floors in the future using another type of floor cleaner.

Causes, Symptoms, and Treatment of Dog Food Allergies

Dog Food Allergies

Interestingly enough, dog food allergies are the least common type of allergy in dogs.

Yet, when people’s dogs start scratching, dog food is often thought to be the first cause of the allergen.

This is very understandable because the itching (or other symptoms) may coincide with a new dog food being given to the dog. Or perhaps a snack that he’s never been fed before.

The symptoms that follow seem to make logical sense to be caused by the food or snack that has recently been given.

The most common allergies in dogs are flea allergies (already covered), followed by environmental allergies that we’ll discuss a little later in this post.

But of course, dog food can be the source of your dog’s suffering, so let’s learn more about this topic now.

Causes of Dog Food Allergies

The first thing to mention here is that dog food allergies are very specific.

Very specific!

By that, I mean that a dog can be allergic to chicken in one brand of tinned dog food, and not allergic to chicken in another brand of tinned dog food.

That may seem very hard to believe!

But with dog food allergies it comes down to proteins.

It can be that the farming methods of one chicken supplier are different to the other chicken supplier, and that is enough to make the chicken proteins different.

It can of course also be down to other ingredients in the dog food and not the chicken at all.

I think that by this stage of reading this post you’ll realize that dog allergy detection relies heavily on detective work!

The most common foods that dogs are allergic to are:

  • Chicken
  • Beef
  • Dairy Products
  • Wheat
  • Lamb
  • Eggs
  • Pork
  • Soy
  • Rabbit
  • Fish

“Hang on!” I hear you saying…

These are all the most common ingredients in dog food!

And you’re right!

And that is why they are the most common food allergens.

The longer your dog is exposed to the same ingredient(s), the more likely it is that your dog will develop an allergy to those ingredients.

The ideal method to feed your dog is by ingredient rotation.

In other words, feed your dog one type of food for 3 months, and then switch to another food for the following 3 months.

If you do that with, let’s say, 4 different ingredients, then your dog will only be eating each type of food once per year in each 3-month time period.

Doing this greatly reduces the chances of your dog developing a food allergy at all.

Symptoms of Dog Food Allergies

While many of the symptoms of dog food allergies concentrate on the gut, there are some other symptoms that are not so obviously related to what you might consider to be a food allergy.

Common symptoms of dog food allergies include:

  • Gastrointestinal problems
  • Gas
  • Diarrhea
  • Ear scratching and visible inflammation of the ears
  • Paw licking or chewing
  • An itchy rear-end

Treatment of Dog Food Allergies

This type of allergy has the most obvious answer, and also the most challenging problem.

The obvious answer:

Stop feeding your dog the food(s) that causes the allergy.

The most challenging problem:

How do you know which food is causing the allergy?

The most challenging problem won’t be difficult at all if you’ve fed your dog the same food for the last 5 years or so. That will be the food that is causing the allergy.

But how many dog owners actually feed their dog the same food year-in and year-out?

People tend to treat their dogs as family members – and rightly so!

But that also usually means that people like to vary their dogs’ diet to make their food less boring.

This is when detecting dog food allergies becomes more of a challenge.

The most effective and reliable way to discover what food your dog is allergic to is by running an elimination diet test.

A while back I wrote another post called: Can a Dog Be Allergic to Chicken but Not Turkey? In that post I include a full test that you can do to test your dog for a food allergy.

While that test is for a chicken allergy, the very same test can be used to test for any ingredient. Simply substitute the chicken for the food you are testing.

Causes, Symptoms, and Treatment of Environmental Allergies in Dogs

Environmental Allergies in Dogs

Environmental allergies in dogs include seasonal and non-seasonal allergies.

Seasonal allergies include allergens that are predominantly abundant in specific seasons such as pollen and grass in summer.

Environmental allergies that are not specific to the seasons include dust and dust mites. A house will tend to have dust and dust mites present at all times of the year.

Additionally, there are many other possible allergens that are found in homes all year round such as air fresheners and cigarette smoke.

Causes of Environmental Allergies in Dogs

Dust Mites (all year round)

If your dog lives indoors, then dust and dust mites are extremely common causes of allergies in dogs.

Dust mites in themselves, are completely harmless to humans and your pets.

But the feces and dead dust mite particles fill the air that you and your dog inhale.

Almost without exception, all houses have dust mites. They are so small that they go unseen, but they are present everywhere.

The remains of dead dust mites contain proteins, and it is these proteins that cause allergies in both dogs and people. The dust that becomes airborne in your home will contain these allergy-causing proteins.

Pollen (mid-spring to early fall)

People without gardens often dismiss pollen as being a possible cause of their dog’s allergy.

But pollen can travel in the air for over 100 miles, so it is clear that not having a garden can immediately be added back to the list of possibilities.

We noticed that with our own dog that his itching became worse in June, and he also began sneezing when returning to the house from the garden.

The timing of his symptoms clearly showed us that he did in fact have a seasonal allergy, and his allergy was very likely pollen.

Dander from Other Animals (all year round)

Dogs can be allergic to other animals including other dogs!

They are not so much allergic to ‘the animal’ but are in fact allergic to the dander from the animal.

Dander is the animal equivalent of dandruff. It is composed of microscopic dead skin cells. The dead skin cells contain proteins and these proteins are the source of the allergen.

Just like us humans, dogs are not allergic to dog hair or cat hair, they are allergic to the dander.

Because dander is invisible to the naked eye, it can be found in the air in any room where there is a pet present.

Mold (all year round)

Spores from mold are yet another invisible allergen present in the air.

Fortunately, while the spores in the air cannot be seen, mold in a room can be seen.

If you see mold in any room (typically rooms where the air becomes damp), then treat the mold with any of the mold-removing cleaning products found in most good stores.

Luckily, mold is very easy to remove, unlike pollen for example.

Symptoms of Environmental Allergies in Dogs

The symptoms of environmental allergies typically affect the skin. So itching is yet again the most noticeable symptom.

Some dogs (like our own), also showed another sign which was sneezing.

Common Body Areas Prone to Itching from Environmental Allergies Include:

  • The Groin
  • Ears
  • Armpits
  • Chest and Belly (general underside of dog)
  • Between the Paw Pads (between toes)
  • Lower Leg Leading to The Paws (wrists)
  • Eyes (appearing watery)

Itching is the main symptom, however, so if your dog is scratching excessively then this can be a clear indication that an allergy is present.

Left untreated, a dog will attempt to fix the problem for himself. This self-treatment will take the form of gnawing, licking and biting at the affected areas.

Rather than helping the situation, your dog will actually make the problem worse. The gnawing and biting typically leads to hair loss, open wounds and scarring.

Professional help is very much recommended rather than allowing your dog to suffer in this way.

Treatment of Environmental Allergies in Dogs

The causes of environmental allergies can be tough to track down.

Equally, trying to self-treat can be almost impossible.

Take for example an allergy to pollen. How do you self-treat this? You cannot keep your dog locked in a pollen-free environment for 5 months each year.

Speaking to your vet is the very best advice for seasonal allergies. Your vet can prescribe antihistamines that can be very effective for these symptoms. Do not be tempted to try human antihistamines.

Another very good reason to consult a qualified veterinarian is that your dog’s symptoms may not be allergy-related at all.

There are certain illnesses in dogs that can cause symptoms very similar to allergies, but they are not allergies.

Getting a proper diagnosis leads to getting the proper treatment.

If it was you and not your dog, you’d want the correct treatment, right?

So always consult a vet if you are unsure.

Life-Threatening Allergies in Dogs

Anaphylactic Shock in Dogs

You have most probably heard the terms, anaphylaxis or anaphylactic shock.

Both terms are the same thing, and refer to an extreme form of allergic reaction. While humans can suffer from an anaphylactic reaction, so too can dogs.

A dog suffering from such a severe allergic reaction may vomit, have difficulty breathing, shake, lose control of the bladder and the bowels.

Not all the symptoms above need to be seen to confirm that a dog is suffering from anaphylaxis.

The swiftness of the onset of the symptoms may be a clue, as the reaction(s) can be produced very rapidly.

Anaphylaxis in your dog is an emergency situation and can be fatal.

If you suspect that your dog is suffering from such a severe allergic reaction than see your vet immediately.

The sooner that you can get your dog to the vet, the better are her chances of surviving the ordeal.

The causes of anaphylactic shock in dogs cannot be presented in a simple list, because the possible causes are too numerous and random.

For one dog, the allergen may be a bee sting, for another dog it may be a severe allergic reaction to dog food. Medication could also be the cause, as could something random that the dog has swallowed.

The main thing to be alert to is a very sudden and severe change in your dogs health.

If your dog is fine one moment and very ill the next moment, then get your dog to the vet!

Treatment of Anaphylaxis in Dogs

Never attempt to treat your own dog for Anaphylaxic Shock at home. This is not the time to reach for the chamomile tea!

A qualified veterinarian will typically administer adrenaline to your dog and possibly hydrocortisone and antihistamines. Your vet will also be monitoring to see if another attack follows the first attack.

A dog admitted to the vet with Anaphylaxis is highly unlikely to be allowed home on the day of the reaction. Further treatment and monitoring is vital and a few days of treatment may be required.

Once your dog has been given the all-clear to leave the vet’s clinic, your vet may give you something called an Epipen. This device is a single-shot adrenaline injection to be used by you if a further attack occurs.

An Epipen is not an all-in-one treatment or cure, it is simply a shot of adrenaline to give to your dog which gives you time to take your dog back to the vet if another attack takes place.

The worry after your dog has suffered from anaphylaxic shock is high. This is especially true as you’ll often not know what allergen caused the attack.

Monitor your dog’s behaviour after all food and be vigilant at all times regarding any medication given.

Also keep an eye on anything in your home or garden that he may take a fancy to and start chewing or eating.

There is no best allergen as such, but simply knowing what the allergen was would be the best case scenario. At least that way you’d know what to keep your dog away from in the future.

I wish you and your dog the best of health.