Trichobezoars (Hairballs) in Dogs

Trichobezoar is a medical term used to describe a hairball. The word “trich” means hair, while a bezoar is any foreign material that obstructs the stomach or intestines. Therefore, a trichobezoar is a gastrointestinal obstruction caused by hair.

While hairballs are typically attributed to cats, they can also cause problems in dogs. Any dog or cat that grooms themselves, or eats the hair of others, is at risk of developing a trichobezoar.

What causes trichobezoars?

Dogs can ingest hair when they groom themselves or when they eat hair they find in their environment. This hair cannot be digested due to the presence of keratin (a fibrous, structural protein), so it usually passes through the intestines and leaves the body in the feces. 

However, in some situations, hair may become tangled on itself or another object in the stomach or intestines. This tangled mass of hair may become too large to pass in the feces, resulting in a hairball, or trichobezoar.

Once a hairball forms, there are two possible outcomes. Many dogs simply vomit up the hairball, leaving you to discover it on your floor, and continue with their normal lives. In some cases, however, this hairball may become lodged in the gastrointestinal tract, leading to an obstruction.

Trichobezoars can occur in any dog, but they are more common in dogs with skin conditions. These dogs tend to lick their skin more often and ingest larger amounts of hair. Over-grooming and ingestion of hair may also be caused by underlying stress or pain.

What are the signs of a trichobezoar?

In many cases, the only sign that your pet has a trichobezoar is a vomited hairball. A dog’s trichobezoar typically has the same cylindrical shape that you may associate with a cat hairball, due to forces that compress the mass of hair as it travels up the esophagus. However, trichobezoars that cause an obstruction are not as easily identified.

If a trichobezoar is causing an obstruction, you may not see hair in your pet’s vomit. Signs of an obstruction my include vomiting, abdominal pain, and lack of bowel movements. If your dog cannot keep down food or water, veterinary treatment is needed.

How are trichobezoars diagnosed?

If your dog is vomiting hairballs, the diagnosis is straightforward. Your veterinarian may recommend diagnostics to search for underlying causes of your dog’s hairballs, such as a thorough skin examination, blood tests, and possible gastrointestinal testing.

If there is an obstruction caused by a trichobezoar, further testing will be needed. Your veterinarian will begin with a thorough physical examination, assessing your dog’s overall health while also palpating (feeling) the abdomen for any evidence of intestinal disease or obstruction.

Next, your veterinarian will likely recommend imaging, to look for evidence of an obstruction. In most cases, radiographs (X-rays) are the first step in assessing for the presence of an obstruction. Depending on the appearance of your dog’s X-rays, your veterinarian may recommend other imaging tests, such as an ultrasound or a contrast study (which examines the flow of a radiopaque material through the intestines).

Your veterinarian may also recommend blood tests, to assess your dog’s organ function and overall health.

What is the treatment for a trichobezoar that is causing an obstruction?

If your dog has an obstruction caused by a trichobezoar, it must be removed. In rare cases, your veterinarian may recommend removal with an endoscope that can be placed down your dog’s esophagus and into the stomach. More commonly, the obstruction is removed via surgery. Surgery allows your veterinarian to access your dog’s entire gastrointestinal tract, so they can find any potential obstructions and remove trichobezoars at multiple sites, if necessary.

Most dogs respond well to surgery if it is performed promptly, before significant intestinal damage has occurred. Your veterinarian will talk to you about your dog’s prognosis before surgery, and about required follow-up care. Most patients remain hospitalized for one to three days after surgery and are then sent home with specific instructions regarding diet, medication, and exercise restriction.

Can trichobezoars be prevented?

Trichobezoars in dogs are often related to underlying skin disease. To prevent the recurrence of trichobezoars, you will need to work closely with your veterinarian to diagnose and manage allergies or other underlying skin conditions.

If your dog’s trichobezoars have another cause, such as ingesting human hair or the hair of other pets in the home, you may need to focus on limiting your dog’s access to hair. Keep trash cans out of reach and keep your floor free of hair to help prevent recurrence.