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Why Is My Dog Biting Itself & Chewing On His Leg?

Do you regularly notice your dog biting himself and chewing on his own leg, among other body parts and areas that he can comfortably (or uncomfortably) reach?

If so, you are definitely not alone.

Dogs are known to use their mouths in the same general way that we humans often use our hands:  to scratch areas that are itchy, dry and/or irritated.

The problem with this strategy—the biting and chewing strategy used by dogs—is it can actually make things worse, and if the affected area also includes a scratch or open wound of some kind, the germs from your dog’s mouth can result in that area becoming infected.

To understand just why our dogs tend to bite and chew on themselves, in this article we will list and explain several potential reasons for the behavior.

And for each of these reasons, we will offer some tips for clearing up the problem area so that the biting and chewing behavior will ultimately cease to remain a problem.

Some Possible Reasons and the Steps You Can Take to Help

As a dog owner, you already know that your pet uses his mouth for a lot more than just eating.

In fact, some canines use their mouth like a multi-tool; biting, scratching and gnawing away at any irritant and skin irritation.

While certainly not the most sanitary, hospital-grade approach to skin and fur care, dogs are going to be dogs and attempting to change their approach through training is bound to come up short.

Instead, we must first identify the problem—the exact reason for the itchy, dry or irritated skin—and implement a solution that will bring relief to your dog, which in turn will lessen the incidences of this biting and chewing conduct.

Below, in no particular order of prevalence or severity, we have listed several potential conditions and circumstances that might cause your dog to bite and chew various parts of his body.

We have also included one or two brief tips for solving each of these possible complaints.

Dry Skin

Dry skin is the number one reason why dogs tend to bite and chew on their legs and other body parts.

It may be difficult to imagine given all their hair/fur, but dogs can and do experience dry skin underneath what might otherwise appear to be a smooth and shiny coat.

So what exactly leads to dry skin in dogs?

Actually, there are many potential culprits.

For instance, during the winter when the weather is harsh and cold, we all (including our dogs) head to the safety of the indoors to hunker down, perhaps even running the furnace to keep the home toasty and comfortable.

These conditions can wreak havoc on a dog’s skin.

Not only does cold, dry weather have the ability to dry out their skin, those conditions only become exacerbated when the heater is blowing full blast.

Aside from the cold and dry wintry conditions, there are many other circumstances that can also contribute to dry, flaky and itchy skin in dogs.

Some of these circumstances and conditions include:

  • Dehydration.  When dogs do not take in enough water during the day, it can gradually make the skin drier and itchier.
  • Certain medications.  Certain medications, including antibiotics and antiparasitic drugs, can lead to dry skin.
  • Medical conditions.  Dry skin can be a side effect for many medical conditions, including diabetes and some cancers, as well as problems with the liver and kidneys.
  • Dermatitis.  Dermatitis is just one major skin condition that can cause dry, red, and patchy skin in dogs.

There is one final factor that can lead to dry, itchy skin in your dog, a factor so prominent that it deserves its own section:  allergies.


We humans are not the only mammals that can be beset by allergies.

The very same allergens and irritants that can lead to dry and itchy skin in us can also have a negative impact on our lovable, four-legged friends.

Particles such as pollen, ragweed, dust and mites, as well as substances like mold, can all trigger an allergic reaction in dogs, and these allergic reactions not only lead to dry skin in some instances, they produce irritants that can remain in a dog’s lush coat throughout the season.

Dogs will then bite and chew on themselves in an attempt to relieve the itch, but these actions not only fail to bring relief, they can eventually make matters worse.

In addition to environmental allergens, there are many other potential irritants that can lead to dry skin.

For example, some dogs may prove to be allergic to the shampoo you are using to bathe them; and others may be allergic to one or more of the foods you give them.

Combatting allergic reactions in dogs can be a painstaking process, but one that is well worth the extra effort.

Your local vet can test your pooch for various irritants and allergens; and once they identify the potential culprit, they can treat your pet with both oral and topical medications that can collectively ease your dog’s suffering.

Infection (Fungal, Bacterial, Skin Parasites)

There are many types of infections that can cause your dog to bite and chew on himself.

Fungal and bacterial infections of the skin can make the skin raw and inflamed, and there will always be some level of parasitic activity on your dog’s coat and skin (due to frequent shedding) that will leave him biting at himself to try and get relief.

Mites are particularly irritating to dogs, as they tend to live in areas of dry skin.

Not only will these parasites cause a lot of itching, they can ultimately lead to poor health in your dog if not addressed.

To avoid fungal, bacterial and parasitic skin infections in your dog, it is important that you bathe him regularly with a mild shampoo—one that is absent of harsh chemicals that can actually make the skin condition worse.

Regular brushing can also be helpful in this regard, as it helps to remove excess, non-growing hair and dead skin from your dog’s coat—the very things that parasites like to call home.

Insect Bites

As any longtime dog owner knows, insect bites and infestations can lead to a lot of biting and chewing behavior.

Fleas are the most common culprit, along with ticks and some other flying insects.

All of these pests can bite dogs, leaving areas of painful and inflamed skin underneath the coat.

If not treated, these bites can ultimately lead to health problems that can include fatigue, weight loss, loss of appetite and more.

There are many commercial products that can be used to both treat and prevent flea and tick bites, including oral medications, flea collars and topical agents.

Natural remedies, all of which are known to repel these problem insects, can also be quite effective.

They include garlic (ingested), lavender, rosemary and mint, whose leaves can be rubbed on a dog’s coat to discourage flea and tick bites.

Blocked Anal Glands

All dogs possess two scent glands located on either side of their anus.

These glands are activated each time a dog defecates—a way for dogs to mark their territory, a territory they often return to time and again when they need to “do their business.”

The only time these anal scent glands are not activated is when they become blocked or stopped up, causing them to swell and become inflamed.

When this happens, you may notice your dog trying to bite his rear end or scoot along the ground, as the condition is very itchy and uncomfortable.

So how do you solve this problem?

Well, if you are not the squeamish type—and you don’t mind subjecting yourself to a truly awful odor—you can always resolve the problem yourself by gently squeezing these glands with your thumb and forefinger.

This usually removes the blockage and allows the glands to function normally again.

If this does not sound like your cup of tea (and who could blame you), make an appointment with your vet instead.

Intestinal Parasites

Another potential reason your dog might chew and bite on his backside is intestinal parasites.

Parasites such as hookworms, roundworms, pinworms and even tapeworms can enter your dog’s digestive tract in a variety of ways.

Once there, they tend to attach themselves to the intestinal walls and feed on blood and undigested food.

Sometimes, they are expelled through the process of defecation, and their presence there can cause unbearable itching for your dog.

If you suspect your dog has intestinal worms/parasites, and he is presenting with symptoms such as diarrhea, loss of appetite and fatigue, along with the itching backside, it is important that you seek treatment for him as soon as possible.

Today there are many medications that can essentially paralyze and kill these parasites before they cause even greater suffering for your pet.


Last but not least, sometimes a dog will chew on and bite himself out of sheer anxiety or for some other emotional reason.

This reason for biting has to be taken just as seriously as all of the aforementioned reasons, if not more serious.

Dogs that bite and chew on themselves when anxious can cause lasting damage to their skin and coats, so it is crucial that you seek help from a pet care professional immediately.

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National Canine Research Association of America