Liver Disease in Dogs: Causes and Diagnosis

Because the liver plays a role in so many systems in your dog’s body, it can be affected by problems elsewhere in the body, like the digestive or immune system. Signs of liver disease can also look like signs of other diseases. This means that there are many potential causes of liver disease in dogs, and several tests may be needed to accurately diagnose the problem responsible, as well as to confirm liver disease itself.

What Causes Liver Disease in Dogs?^1–3 

Liver disease in dogs has many possible causes, including inherited dog liver conditions, infections, chronic diseases, exposure to toxins, and some kinds of medications. Because the liver plays such a central role in metabolism and detoxification, it is especially vulnerable to many types of damage.

Genetic and Breed-Related Conditions

Some dogs are born with liver abnormalities or genetic tendencies that make them more likely to develop liver problems later in life. Examples include:

• Copper storage disease (copper-associated hepatitis). Certain breeds, such as Bedlington Terriers, Dalmatians, Doberman Pinschers, Labrador Retrievers, and West Highland White Terriers, are prone to accumulating too much copper in their liver. Excess copper can cause liver inflammation and scarring.
• Congenital portosystemic shunt (PSS). This is a condition where blood bypasses the liver, reducing its ability to filter toxins. It is often diagnosed in young dogs, with Maltese and Yorkshire Terriers being commonly affected.
• Other congenital anomalies. Some dogs are born with underdeveloped liver blood vessels (microvascular dysplasia) or bile duct abnormalities, which can lead to liver dysfunction as they age.

Toxins and Medications

The liver is the primary organ for detoxification, which means it is often exposed to harmful substances. Damage can occur from:

• Household toxins. Some moldy foods, certain mushrooms, and even some plants (like sago palm) can be fatal to dogs.
• Chemicals and heavy metals. Pesticides, herbicides, and lead may cause liver damage if ingested.
• Medications. Long-term use or high doses of certain drugs, such as phenobarbital, primidone, phenytoin (anti-seizure medications), lomustine (chemotherapy), and even some pain relievers and anti-inflammatories, can cause liver injury over time.

Liver Infection in Dogs

A number of infections can target the liver or cause inflammation as a secondary effect:

• Leptospirosis. A bacterial disease spread through contaminated water or soil that often damages the liver and kidneys.
• Bacterial infections. Secondary infections from gastrointestinal disease or systemic illness can inflame the liver (reactive hepatitis).
• Parasitic infections. Certain parasites, like liver flukes, can directly damage liver tissue.
• Viral causes. While rare, some viruses can affect liver function.

Immune-Mediated and Inflammatory Disorders

In some dogs, the immune system mistakenly attacks the liver (autoimmune hepatitis), causing ongoing inflammation and scarring. This condition is often suspected when no clear infectious, toxic, or metabolic cause can be identified.

Endocrine and Metabolic Disorders

Diseases that affect metabolism are also on the list of what causes liver problems in dogs:

• Diabetes mellitus and hypothyroidism. Can cause fatty deposits (lipidosis) or vacuolar hepatopathy (liver cell swelling).
• Cushing’s disease (hyperadrenocorticism). Excess cortisol production often leads to steroid-induced changes in the liver.

Liver Cancer in Dogs

The liver can be affected by primary liver cancers (like hepatocellular carcinoma) or by cancers that spread (metastasize) from other areas, such as the spleen, pancreas, or gastrointestinal tract.

Aging and Degenerative Changes

Older dogs are more prone to liver disease because of age-related changes in blood flow and cell function. Chronic low-level exposure to toxins or medications over a lifetime can also contribute to gradual liver decline.

Bottom Line

Because there are so many possible causes of liver disease in dogs, it’s essential to work with your veterinarian to determine why your dog’s liver enzymes are elevated or why clinical signs are present. Understanding the underlying cause is critical to choosing the right treatment for high liver enzymes in dogs and improving your dog’s quality of life.

How to Confirm Dog Liver Disease: Veterinary Diagnosis

Diagnosing liver disease requires multiple steps because the liver is involved in many body systems and different diseases can cause similar signs. One common step in diagnosis is confirming high liver enzymes in dogs. Your veterinarian will likely recommend some of the following tests:

Physical Examination

• Visual assessment. Your veterinarian will check for jaundice (yellowing of the gums or eyes), abdominal swelling, and changes in body weight or muscle mass.
• Palpation. The abdomen is gently examined to detect an enlarged liver, pain, or fluid buildup.

Blood Tests^1,3

Bloodwork provides essential information about liver function and overall health:

• Complete blood count (CBC). Evaluates red blood cells, white blood cells, and platelets. Anemia, signs of infection, or clotting abnormalities can indicate liver dysfunction or complications.
• Serum chemistry panel. Measures albumin, bilirubin, blood glucose, blood urea nitrogen, cholesterol, total protein, and liver enzymes (ALT, ALP, AST, GGT). Changes in these values (such as elevated liver enzymes in dogs) can signal impaired function or liver damage in dogs.
• Clotting profile (PT, aPTT). Because the liver produces clotting factors, these tests can detect bleeding risk associated with advanced liver disease.

Bile Acid Test

A bile acid stimulation test checks how well the liver clears bile acids from the bloodstream and is often used when enzyme changes are mild or ambiguous.

Urine Tests

Urinalysis can detect bilirubin in the urine, abnormal concentration, or signs of kidney involvement secondary to liver disease.

Imaging

• X-rays. Provide a general view of liver size and position.
• Ultrasound. Gives more detail about liver structure; also identifies cysts, tumors, or abnormal blood flow and can guide safe biopsy collection.
• Advanced imaging (CT or MRI). May be recommended in complex cases or when surgical planning is needed.

Liver Biopsy

A biopsy is the gold standard for diagnosing the exact type of liver disease and guiding treatment:

• Methods. May include needle biopsy (ultrasound-guided), laparoscopic biopsy, or surgical wedge biopsy.
• Purpose. Determines whether disease is inflammatory, infectious, metabolic, or cancerous and checks for copper accumulation or fibrosis (scarring).

Special Testing

• Infectious disease testing. Leptospirosis testing or polymerase chain reaction (PCR) panels for infectious causes.
• Genetic testing. For breeds prone to copper storage disease or congenital shunts.

Bottom Line

Because liver disease can develop silently, these tools are essential for identifying both the severity and cause of liver damage before it becomes life-threatening.  

For more expert tips on dog health, explore our other dog symptom articles.  

References

1. Stockman J. Nutritional management of hepatobiliary diseases in dogs and cats. Vet Clin North Am Small Anim Pract. 2025;55(4):579–593.

2. Nelson, Couto RW, Guillermo C. Small Animal Internal Medicine [Kindle edition]. Elsevier Health Sciences; 2020.

3. Webster CRL, Center SA, Cullen JM, et al. ACVIM consensus statement on the diagnosis and treatment of chronic hepatitis in dogs. J Vet Intern Med. 2019;33(3):1173-1200.