The reasons why dogs lose hair on their tails can be numerous. Some can be rather straight forward, others may be more subtle. Sorting through the possibilities often requires intervention of a veterinarian who will run some basic tests. Veterinarian Dr. Ivana shares possible causes of hair loss on dogs tails. 

The Wonder of Dog Tails 

Dog tails come in many sizes and shapes, from curly through fluffy to nubby – we love them all wildly when they are wagging.

The dog's tail is much more than just a decoration. Dogs express their emotions through their tails, and they help them keep physical balance. What is more, the tail can say a lot about the dog’s emotional and physical wellbeing. There are many fascinating facts about dog tails!

 But what happens when a dog starts losing the hair on the tail? What causes such hair loss? And can the hair grow back? Following are several considerations and possible causes of dogs losing hair on their tail. 

Chewing Off vs. Falling Out

If you notice hair loss on your dog’s tail, the first step towards addressing the problem is determining whether your dog chews the hair off the tail or whether it is falling out.

If the dog is chewing off its tail hairs, the remaining hairs will be broken, rough, and frizzy. The surrounding hairs can also be sticky and wet with dog saliva. 

What is more, the bald patches are likely to be red and inflamed. In cases of aggressive chewing, open sores will be visible on the tail skin.

On the flip side, if your dog does not chew on its tail at all and the tail hairs are falling out on their own, the remaining hairs will not be broken and will appear smooth. There will not be stickiness and moisture due to dog saliva presence. Ultimately, the skin, that is easily visible on the bold patches, will be ordinarily colored and lacks signs of inflammation.

Dogs Chewing Off Tail Hair Due to Allergies

Excessive itchiness is likely to trigger uncontrolled chewing. The most common cause of excessive tail chewing is allergies. Several different types of allergies can be held responsible. 

In many cases, the culprit is flea allergy dermatitis. Individuals allergic to flea saliva can exhibit severe allergic reactions manifested with excessive itchiness and dermatitis even if bitten by a single flea. In cases of more severe flea infestations, the clinical manifestation will be proportionally more drastic. 

The treatment involves getting rid of the fleas and treating the tail locally. Luckily, the modern market offers a plethora of anti-flea treatments that come in different forms – spot-on products, chewable pills, and collars. Your vet will explain the pros of each treatment and advice, which one is best for your dog.

Dogs with environmental allergies (dust, mites, pollen, grass) and food allergies can also feel itchy to the point they start making self-inflicted injuries due to excessive chewing and scratching. 

In such cases, the triggering allergen should be identified and, if possible, removed or at least minimized. If this is not possible, the dog will be prescribed antihistamines and corticosteroids. The tail should be locally treated based on the severity of the inflicted damage.

Dogs Chewing Off Tail Hair Due to Scabies 

A dog may start chewing off its tail hairs if it has scabies. Scabies is a parasitic skin infection caused by the Sarcoptes scabiei mite. 

These mites live on the skin's surface, but when it is time to reproduce, they burrow into it and lay their eggs deep into the skin layers. The burrowing is what causes excessive itching and skin rashes.

 The treatment includes administering anti-parasitic treatments (usually a combination of injections and spot-on treatments or chewable pills). Local, topical treatment is commonly advised.

Dogs Chewing Off Tail Hair Due to Worms 

A dog may excessively bite, lick or scratch its tail (particularly its base, near the anus) if it has intestinal worms. Worms, particularly tapeworms, irritate when coming out of the dog's anus. To prevent such problems, it is vital to have your dog de-wormed regularly.

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Dogs Chewing Off Tail Hair Due to Anal Gland Issues 

Dogs may excessively bite their tail basis if they have impacted and infected anal glands. Cleaning the glands and administering systemic antibiotics will result in clearing of the glands and eventually solving the problem.

Rat tail in a dog Source: Wikimedia,  Alopecia on the tail typical of canine hypothyroidism 

Rat tail in a dog Source: Wikimedia,  Alopecia on the tail typical of canine hypothyroidism 

Dog Losing Hair Due to Hormonal Imbalances

Hormonal imbalances are the most common cause of tail hair falling out on its own. The most frequently reported hormonal imbalances in dogs include hypothyroidism and Cushing's disease (hyperadrenocorticism).

An underactive thyroid gland, hypothyroidism, will result in a deficiency of thyroid hormones. Sadly, hypothyroidism is reported to affect one out of 250 dogs. In four out of five sufferers, hypothyroidism is an immune-mediated disease in which the thyroid is attacked and destroyed by the dog's immune system.

 Dogs with hypothyroidism will experience lethargy, weight gain, weakness, increased skin pigmentation, and less exercise tolerance.

 Since the thyroid hormones are responsible for proper hair growth, affected dogs will also experience low hair quality and thinning of the hair, followed by hair loss. When the tail loses most of its hair, it starts resembling a rat's tail, which is why this condition is popularly known as rat tail syndrome. The treatment of choice is administering a synthetic thyroid hormone, known as L-thyroxine.

Cushing's disease is over-activity of the cortisol-producing area of the adrenal gland. The most common cause is the pituitary gland producing an excess of adrenocorticotropic hormone (ACTH). In cases of pituitary-dependent Cushing's disease, the underlying cause is small tumors in the pituitary gland. 

The disease may also be caused by tumors in the adrenal gland or excessive medical use of corticosteroids (iatrogenic Cushing's disease). 

Some dog breeds are genetically predisposed to developing Cushing's disease. Affected dogs drink and urinate excessively and are continuously hungry. They develop a pot-bellied appearance and are weaker and more lethargic. Ultimately, their hairs start falling off. 

Pituitary-dependent Cushing's disease is treated with drugs that suppress pituitary gland over-activity. The ideal treatment for Cushing's disease due to an adrenal tumor is the surgical removal of the tumor. Iatrogenic Cushing's disease usually disappears spontaneously once the dose of corticosteroid is gradually reduced.

Now That You Know....

A dog may start losing its tail hair due to a plethora of reasons. Some reasons are relatively harmless, while others are more serious and warrant an immediate trip to the vet’s office. 

Determining the exact underlying cause on your own is impossible. Therefore, if you notice your dog’s tail is starting to lose hair, do not hesitate to schedule an appointment with your vet. 

Hopefully, there will be nothing serious, and the vet will put your mind at ease. On the other hand, if it is something more severe, the vet will initiate a suitable treatment early on.

About the Author

Dr. Ivana Crnec is a graduate of the University Sv. Kliment Ohridski’s Faculty of Veterinary Medicine in Bitola, Republic of Macedonia.


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