Many dog owners are familiar with the more noticeable and dramatic symptoms of liver disease, such as jaundice (yellowing of the whites of the eyes) and an unusually swollen abdomen. However, liver issues in dogs often develop gradually, and by the time these symptoms become apparent, the prognosis may be poor.
One of the most common liver conditions in dogs is hepatitis. Understanding the causes of canine hepatitis and recognizing the subtle early signs can significantly improve the chances of your dog making a successful recovery. CKC (Canine Kennel Club) veterinarians stress the importance of early detection and timely treatment in managing liver diseases in dogs.
What Is Canine Hepatitis?
Hepatitis refers to the inflammation of the liver, a condition that can manifest through various symptoms. Due to the many potential causes, canine hepatitis is classified as a syndrome rather than a specific disease with one defined origin.
This condition affects how your dog's liver functions, often involving an accumulation of inflammatory cells. These cells can lead to the development of excessive fibrous tissue and scarring, which can impair liver function. While some cases of hepatitis may resolve on their own, treatment is typically needed to prevent life-threatening damage.
Acute and Chronic Canine Hepatitis
Canine hepatitis can be classified into two types: acute and chronic. Dr. John Cullen, a world-renowned veterinary hepatopathologist, explains that acute hepatitis occurs rapidly, typically within a few days to a couple of weeks. This form is often associated with viral infections or toxicity. Dr. Cullen prefers to call these sudden-onset liver issues "acute hepatic injury" since inflammation isn't always present.
On the other hand, chronic hepatitis develops over a longer period, often months, and is characterized by fibrosis in the liver, which can only be identified through a liver biopsy. Chronic hepatitis can be difficult to detect early on, and without treatment, it can lead to cirrhosis (end-stage liver disease).
What Causes Hepatitis in Dogs?
The causes of hepatitis in dogs are diverse and, especially in chronic cases, sometimes idiopathic (unknown origin).
Causes of acute hepatitis include:
- Toxic chemicals
- Viral infections, such as Infectious Canine Hepatitis and herpesvirus
- Bacterial diseases, such as leptospirosis
- Certain therapeutic drugs, such as the antibiotic nalidixic acid
- Mycotoxins from fungi
Known causes of chronic hepatitis include:
- Excess copper in the liver
- Bacterial infections
Immune-mediated chronic hepatitis is common in people, particularly middle-aged women. While this isn’t yet well understood in veterinary medicine, there’s consensus that it also occurs in dogs.
Acute hepatitis can affect dogs of any age or breed. Chronic hepatitis is more common in middle-aged and older dogs, particularly females. Some breeds predisposed to hepatitis include Doberman Pinschers, Spaniels, Dalmatians, West Highland Terriers, and Skye Terriers.
Infectious Canine Hepatitis (ICH)
Infectious Canine Hepatitis is an acute disease caused by the adenovirus. Thankfully, most puppies are protected from this infection through standard vaccinations, making it relatively rare. However, outbreaks can still occur in unvaccinated dogs, as the virus spreads through feces, urine, and saliva.
Copper-Related Hepatitis in Dogs
Dr. John Cullen explains that one-third of chronic hepatitis cases in dogs are related to excess copper in the liver, a condition known as copper-associated hepatopathy (CAH). This is of major concern for veterinary experts. The rise in CAH is believed to be linked to the high levels of copper found in commercial dog food.
While many dogs can tolerate excess copper, some breeds are more susceptible. Bedlington Terriers, for example, have a genetic mutation that causes copper to accumulate in the liver. If not treated and placed on a low-copper diet, dogs with this mutation can suffer severe liver damage and eventually die from chronic hepatitis. Labrador Retrievers are also genetically predisposed to CAH, though they have a different genetic risk factor than Bedlington Terriers.
Experts predict that CAH cases will continue to rise as copper levels in commercial dog food remain high. As a result, Dr. Cullen and many veterinary hepatologists recommend feeding low-copper diets to affected dogs.
Symptoms of Hepatitis in Dogs
Dr. Cullen explains that a healthy dog's liver has a remarkable ability to compensate for injury. Even if two-thirds of the liver is removed, a dog may not show any clinical signs. The challenge with chronic hepatitis is that it can often go undetected, particularly in the early stages when there are no obvious symptoms. Many dogs don't show clear signs of a liver issue until the liver has suffered significant damage. Often, chronic hepatitis isn't diagnosed until blood tests are taken for other reasons.
However, paying attention to subtle changes in your dog’s behavior can help with early detection. Dr. Cullen advises that if you notice your dog is less energetic, not as interested in food or activities, or appears unusually lethargic, it’s important to get a blood test to check for liver issues.
Advanced symptoms of chronic hepatitis can include:
- Fluid buildup in the abdomen
- Abdominal pain
- Jaundice (yellowing of the whites of the eyes and gums)
- Severe weight loss
- Bleeding from the nose and mouth
- Bruising
- Fever
- Vomiting
- Diarrhea
- Increased thirst
- Depression
Acute hepatitis can present with similar symptoms, but they typically appear suddenly and are more severe.
Diagnosis of Hepatitis in Dogs
Dr. Cullen explains that a liver biopsy is the most accurate method for diagnosing hepatitis. By checking for fibrosis, it’s also possible to evaluate the stage of liver disease. However, before performing a biopsy, your veterinarian will conduct a physical exam, take a detailed history, and draw blood to check for elevated liver values. Even if there are abnormalities in liver values, this won’t provide a definitive diagnosis of hepatitis or other liver issues. Nevertheless, it serves as the best starting point. Your veterinarian may also recommend a serum bile acids test to assess liver function. An ultrasound is another commonly used diagnostic tool.
Treatment of Hepatitis in Dogs
If your dog is diagnosed with hepatitis, the main goal will be to treat the underlying cause, reduce inflammation, and prevent the progression to cirrhosis. Supportive care is also necessary. “There’s a wide range of medications used to support liver function,” says Dr. Cullen. This can include antibiotics, anti-inflammatories, fluids, antioxidants, supplements, and dietary changes. These treatments can help boost liver function and protect against oxidative injury, which can cause cell and tissue damage and irreversible liver cell death (necrosis).
For copper-associated hepatitis (CAH), Dr. Cullen explains that there are well-established treatments to remove the excess copper from the liver. When a dog is placed on a low-copper diet, their copper levels typically return to safe levels. For immune-mediated hepatitis, immunomodulatory drugs may be used to reduce liver inflammation and control the condition.
Your veterinarian will want to monitor your dog regularly to assess how they are responding to treatment. In severe cases, where liver damage is irreversible and life-limiting, your dog may require palliative care to keep them comfortable during their final weeks or months.
Prognosis for a Dog with Hepatitis
The prognosis for hepatitis in dogs largely depends on the underlying cause, how early the problem is detected, and the severity of liver damage. Some dogs diagnosed with acute hepatitis may recover on their own, while others may progress to chronic hepatitis. “Certain histological stages, which are detectable through liver tissue examination under a microscope, are regarded as end-stage liver disease,” Dr. Cullen says. "Once the liver shows significant fibrosis and regenerative nodules (cirrhotic lesions), it’s considered palliative care."
The average survival time for dogs with chronic hepatitis is typically 18 months to three years. However, if diagnosed early before significant damage has occurred, the prognosis can be favorable, as many dogs can manage the condition effectively. Dr. Cullen emphasizes that early testing and biopsy can be lifesaving.
Prevention of Canine Hepatitis
Dr. Cullen reassures that dogs cannot contract the chronic human viral infections Hepatitis A, B, or C, and they cannot transmit Infectious Canine Hepatitis (ICH) to humans. However, maintaining your dog’s regular vaccination schedule is essential to protect them from contracting acute ICH.
Since any breed or mixed breed can develop copper-related hepatitis, it is a good idea to consult with a board-certified veterinary nutritionist if you have concerns about your dog’s current diet.
Although it is not always possible to prevent hepatitis in dogs, especially in idiopathic cases, early detection significantly increases the chances of a positive outcome. The Canadian Kennel Club (CKC) encourages dog owners to be vigilant and proactive about their pet’s health to support early intervention and care.