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By Diana Bocco

Loss of hair on a dog’s tail can be indicative of a few possible problems. While a proper diagnosis cannot be made without an exam, Dr. Judy Morgan, DVM, an integrative veterinarian who runs two animal hospitals in New Jersey, says that fleas are the first thing she looks for whenever she sees hair loss on the tail or tail base. This is particularly the case during warm weather months, which is prime flea season, she explained.

Another common cause of hair loss is allergies. “Unlike people, who typically respond with respiratory issues like a scratchy throat, runny nose, and itchy eyes, when dogs have allergies, it’s all about the skin,” explained Dr. Jeff Werber, DVM, owner and chief medical director at Century Veterinary Group in Los Angeles.

“Regardless of the source of the allergy – whether it’s food, pollen, fleas, something environmental, or even around the house – dogs typically respond with frequent or constant scratching, licking, biting, scooting and/or rubbing, which can cause hair loss or skin damage on the body, face and the tail,” said Werber.

Worms and Other Icky Things

Worms (especially tapeworms) coming out of the anal area can create irritation, causing your dog to lick and bite at the area, as well as around the tail. “You may sometimes see weight loss, rough hair, vomiting worms, diarrhea, and bloody diarrhea,” says Oppenheimer.

“You may also see a change in the dog’s behavior; they may be weak, lethargic, and less playful.” However, some dogs with worms have no obvious symptoms. Your veterinarian may recommend a fecal examination or empiric treatment if he or she suspects that your dog may have intestinal worms.

Flea allergy is also a common cause of hair loss on the tail. In fact, the tail and groin are preferred sites for fleas, said Osborne. “Fleas cause flea allergy dermatitis in dogs, which is the leading cause of dog allergies, especially in the summer,” Osborne explained.

Dogs with flea allergies can become incredibly itchy, even if only a few fleas are present. Therefore, not being able to find fleas on your dog does not rule them out as a cause for your dog’s itchiness.

“With flea allergy dermatitis, we often see what we call a “Christmas tree pattern,’” explains Morgan.

“The dog has a good coat over the shoulders, it gets thinner on the sides and flanks, and is bald at the rump and tail,” she said. “This is because that's where the dog can reach most easily to lick and chew.” 

Allergies and Allergic Reactions

Frequent itching and scratching can also be caused by allergies to food or environmental allergens like pollens or dust, says Werber. “The location of the itch can sometimes give us an idea of the cause of the allergy.”

And while allergies are often complicated, Werber points out that there are treatments for various types of allergies that your veterinarian can prescribe after diagnosis.

Hormonal Havoc

Hypothyroidism and other hormonal (endocrine) diseases tend to cause "bilaterally symmetrical alopecia," which is hair loss that mirrors from one side to the other, Morgan said. “It tends to start over the flanks or loins and will spread back towards the tail. This is complete loss of hair, not broken hairs from licking and chewing like we see with allergic problems.”

Other Causes of Hair Loss

A rarer cause for loss of hair on the tail is due to chewing connected to pain, said Oppenheimer.

“Some diseases can cause inflammation of the skin or on the nerve endings,” he said. “The pain can be as severe as human fibromyalgia, so painful that a dog has to chew on their tail.”

Treatment for hair loss that results from pain is based on the underlying cause and can include anything from medications to treat infections to surgery, said Oppenheimer.

Emotional Issues and Hair Loss

Once medical issues have been ruled out or addressed, the next step is to determine whether a behavioral problem might be causing the dog’s hair loss. Behavior modification can be accomplished through positive reinforcement, natural therapies (herbs, essential oils, and pheromones), exercise, and lots of love, says Dr. Carol Osborne, DVM, the author of Naturally Healthy Dog and the nation’s first veterinarian to be board certified as a diplomat of the American Academy of Anti-Aging Medicine.

Just like humans, dogs can suffer from biting (or licking) that is related to stress or other psychological problems. It's the doggie equivalent of biting your nails. And because the tail and feet are easily accessible, those are the spots where you might see hair loss and damage more frequently.

“[Obsessive] licking can be related to stress and emotional trauma for dogs that have been confined for long periods of time,” says Dr. Victor Oppenheimer, DVM, veterinary director at the Hospital de Animales Perla del Sur in Puerto Rico.

“OCD [obsessive compulsive disorder] is a common disease in dogs left alone or confined for a long time without toys; dogs get so bored that self-licking becomes obsessive.”

“In extreme cases, the vet can prescribe antipsychotic drugs to take every day for six months,” says Oppenheimer. “Then we would reduce the pet’s medication slowly over three months to find the minimum medication needed.” Of course, addressing the root cause of the dog’s behavior is also an essential part of treatment.

This article was verified and edited for accuracy by Dr. Jennifer Coates, DVM


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