Why Is My Dog Biting His Tail and Back? Causes and Relief

Name: Why Is My Dog Biting His Tail and Back? Causes and Relief
Creator: Dr. Zubair Khalid

By Dr. Zubair Khalid, DVM, MS, PhD · 2026-10-03

If your dog keeps biting his tail, the answer is usually not a quirky habit. Most tail and rear-end chewing comes down to itching, parasites, anal gland trouble, or pain somewhere in the back end. The location of the chewing is your best clue, so this guide takes a body-region approach to help you narrow it down.

This article is educational and is not a substitute for veterinary diagnosis or treatment.

Quick Answer

Chewing at the tail tip or the skin right around it points toward fleas, a hot spot, or a skin infection.
Chewing at the base of the tail, the anus, or the rear legs often points toward anal glands or allergies.
Chewing along the lower back and spine can be a pain signal, and back pain in dogs is under-recognized by many clinicians [1].
Fleas and other parasites vary by region and season across the United States, so where you live and what month it is both matter [2].
Sudden, intense, nonstop chewing is different from occasional grooming and needs a same-day call to your veterinarian.

What Normal Grooming Looks Like vs. a Problem

Dogs groom themselves. A few quick nibbles at the tail base, a lick at the flank, and then they move on. That is normal.

A problem looks different. You may see your dog keep chewing his tail for minutes at a time. He may spin in circles to reach it. The fur may look thinned, stained, or wet in one spot. The skin underneath may be red, raw, scabby, or smelly.

Some dogs chew when they are relaxed. Others do it in bursts, often at night or after meals. Some stop when you say their name. Others do not stop at all, and that intensity is a warning sign.

Owners are actually good at spotting pain-related behavior changes. In one study, the most commonly reported changes in dogs recovering from a painful procedure were changes in walking, playing with objects, and playing with their owner [3]. Chewing at the back end can be a similar signal. Your dog may be telling you something hurts.

Why Is My Dog Biting His Tail and Back? The Main Causes

The table below groups the most common reasons by where your dog focuses and how fast you need to act.

Cause	Typical clues	How urgent
Fleas and flea allergy	Chewing at tail base and rump, live fleas or flea dirt, itching worse in warm months	Soon, same week
Other parasites (mites, intestinal worms)	Scooting, dull coat, itching, diarrhea, regional and seasonal patterns	Soon, same week
Skin infection or hot spot	Moist, red, hairless patch, odor, sudden onset	Within 24 to 48 hours
Anal gland problem	Scooting, licking under the tail, straining to poop, foul smell	Within 24 to 48 hours
Allergies (environmental or food)	Itchy ears, paws, and rear end, licking paws, seasonal flares	Routine visit
Back or spine pain	Chewing at the lower back, stiffness, reluctance to jump, yelping	Same day if sudden
Boredom or stress behavior	Chewing when alone, destructive behavior, normal skin	Routine visit
Nerve or tail injury	Tail hangs limp, no wag, pain at the tail base	Same day

Fleas and Parasites

Fleas are the classic reason a dog chews the tail base and rump. Flea bites cause intense itching, and dogs with flea allergy react to just a few bites. Parasite patterns in the United States are not uniform. A 2023 analysis of 48,510 canine cases found at least one parasite in 12.27 percent of them, and the most common were Giardia intestinalis, hookworms, roundworms, Cystoisospora, and whipworms [2]. Regional differences significantly influenced overall parasitism rates [2]. That means a dog in one state may face very different risks than a dog in another.

Season matters too. Parasite prevalence shifts by month and region [2]. If your dog's chewing started in spring or summer, parasites move up the list.

Skin Infections and Hot Spots

When a dog chews one spot, the skin breaks down. Bacteria move in. The spot gets red, moist, and painful, and then your dog chews more. This cycle can happen fast, sometimes overnight. A hot spot on the tail or rump is a common version of this, and it needs treatment, not just stopping the chewing. You can read more about that pattern in Dog Hot Spot on Tail: Causes and Treatment.

Anal Gland Trouble

The anal glands sit on either side of the anus. When they fill up or get infected, dogs scoot, lick, and chew at the area under the tail. You may notice a fishy smell, straining to poop, or a swollen spot near the anus. This is uncomfortable and often needs a veterinary visit to empty or treat the glands.

Allergies

Allergies are a top cause of rear-end itching. Environmental allergies (pollen, dust mites, mold) and food allergies both cause itching that often shows up at the ears, paws, and around the tail base. Allergies are usually a long-term management issue, not a one-time fix.

Back and Spine Pain

This cause gets missed. Back pain in dogs is not well measured, and veterinarians disagree about how common it is. Perceptions of back pain and dysfunction varied widely among surveyed veterinarians, and specialists in sports medicine, rehabilitation, acupuncture, and spinal manipulation reported it more often than other practitioners [1]. Clinicians who examined individual spinal segments or palpated for muscle trigger points found more back pain than those who did not [1].

What does that mean for you? If your dog chews at his lower back or spine instead of his tail, pain is a real possibility. He may also be stiff, slow to rise, or unwilling to jump on the couch. A dog with back pain may also limp, and limb and spine problems can overlap. See Why Is My Dog Limping Front Leg On His Back for related signs.

Behavior and Stress

Some dogs chew their tail or back out of boredom, confinement, or anxiety. This is more likely when the skin looks normal, the chewing happens mainly when your dog is alone, and there are no other medical signs. Behavior problems rarely appear alone, so it helps to look at the whole picture in Why Is My Dog Having Behavior Problems.

Red Flags That Make It an Emergency

Call your veterinarian right away or go to an emergency clinic if you see any of these.

The chewing is nonstop and your dog cannot be interrupted.
There is heavy bleeding, a deep wound, or the tail tip is damaged or missing.
The tail is limp, crooked, or obviously broken.
Your dog is crying, panting, pacing, or cannot settle.
The area is swollen, hot, and spreading fast.
Your dog is vomiting, has diarrhea, or seems weak or wobbly.
Your dog cannot urinate or poop, or is straining with no result.

Sudden severe pain needs same-day care. Do not wait to see if it improves on its own.

Safe Things You Can Do at Home While You Wait

You cannot diagnose your dog at home, but you can keep things from getting worse.

Stop the chewing with a cone or a soft recovery collar. This breaks the itch-scratch cycle and protects the skin.
Check for fleas. Look at the tail base and rump with a fine comb. Flea dirt looks like pepper flakes and turns reddish when wet.
Look at the skin. Note the color, moisture, smell, and size of any bare or red patch. Take a photo so you can show your veterinarian.
Do not apply human creams, ointments, or steroid products to your dog. Many are not safe if licked off.
Do not try to express the anal glands yourself unless your veterinarian has shown you how. You can cause injury or infection.
Keep a simple log. Write down when the chewing happens, how long it lasts, and what else you notice. This helps your veterinarian a lot.
Keep your dog on flea prevention year-round. Ask your veterinarian which product fits your region and your dog's health.
Do not give any medication unless your veterinarian prescribes it. Your veterinarian calculates the dose from your dog's weight and health.

If your dog is shaking, restless, or seems painful, that can be a pain signal. See Why Is My Dog Shaking? for more on what that can mean.

What Your Veterinarian Will Check and Test

Your veterinarian will start with a full physical exam. That includes the tail, the anus, the anal glands, the skin, and the spine. They will palpate the back and may check individual spinal segments and muscle trigger points, since these techniques help reveal back pain that a general exam can miss [1].

Depending on what they find, they may recommend:

Skin scrapings or tape preparations to look for mites and infection.
A flea comb check and a review of your flea prevention.
A fecal test for intestinal parasites, since parasites are common and vary by region and season [2].
Anal gland expression or imaging if the glands are impacted or infected.
Allergy testing or a diet trial if itching is widespread and long-standing.
X-rays or other imaging if back or tail pain is suspected.
Bloodwork if infection, pain, or other illness is a concern.

Treatment follows the cause. Fleas get flea control. Infections get appropriate medication. Anal glands get emptied or treated. Allergies get a long-term plan. Pain gets pain management. Behavior gets a behavior plan.

Prevention and Monitoring

Prevention depends on the cause, but a few habits help most dogs.

Stay current on parasite prevention all year. Regional and seasonal patterns mean risk changes with where you live and the time of year [2].
Check the tail base and rump weekly. Run your hands over the skin and look for redness, bald spots, or moisture.
Keep nails trimmed and check the rear end after walks in tall grass or woods.
Address itching early. A small hot spot is easier to treat than a large infected one.
Watch for subtle pain signs. Changes in walking and playing are among the behaviors owners notice most in dogs with acute pain [3].
Manage weight and activity. Extra weight adds strain to the back and joints.
Follow up. If your dog improves but the chewing returns, call your veterinarian. Recurrence is common with allergies and parasites.

Limitations and When to Contact a Veterinarian

This guide cannot tell you what is wrong with your dog. Every case needs a veterinarian who can examine your dog in person.

Contact your veterinarian the same day if your dog has sudden intense chewing, a raw or bleeding area, a limp tail, or signs of pain like crying or pacing. Go to an emergency clinic now if there is heavy bleeding, a deep wound, a broken tail, or your dog cannot urinate or poop. Schedule a routine visit if the chewing is mild but ongoing, if the skin looks normal, or if you have tried home care for a few days with no improvement.

Frequently Asked Questions

Why does my dog keep chewing his tail?

Most tail chewing is driven by itching, fleas, a skin infection, anal gland trouble, or pain. The exact spot matters. Chewing at the tip suggests a skin or flea problem, while chewing at the base and rear can point to anal glands or allergies.

Is tail biting ever just a habit?

It can be, but behavior is a diagnosis of exclusion. Boredom and stress can cause repetitive chewing, yet the same behavior shows up with itching and pain. A veterinarian should rule out medical causes before anyone calls it a habit.

Can I use human itch cream on my dog's tail?

No. Human creams and ointments are often not safe for dogs, especially when licked off. Ask your veterinarian for a product made for dogs, and never give any medication without a veterinary dose calculated for your dog's weight and health.

How do I know if my dog's back is hurting?

Watch for stiffness, reluctance to jump, slow rising, yelping when touched, and chewing along the spine instead of the tail. Back pain is under-recognized in dogs, and some examination techniques reveal it more reliably than others [1]. If you suspect pain, book a visit.

When should I worry about my dog biting his back?

Worry when the chewing is sudden, intense, or nonstop, or when you see redness, swelling, bleeding, or a change in behavior. Also worry if your dog seems painful, weak, or unable to settle. Those signs mean a same-day call to your veterinarian.

References

Factors affecting veterinary perception of the prevalence of back pain and dysfunction in dogs and horses. Frontiers in veterinary science, 2026.
Regional and seasonal variability in canine parasitism across the United States. Veterinary parasitology, 2025.
Acute pain sign recognition by dog owners in a home setting. PloS one, 2026.