SYMPTOM
Jaundice (yellowing of skin or eyes)
A yellowish discolouration of the whites of the eyes, the inner ear flaps, the gums, or the skin, most visible in lightly pigmented areas and indicating elevated bilirubin levels.
Hepatic (Liver) Disease
Jaundice most commonly reflects dysfunction of the liver's ability to process and excrete bilirubin, a breakdown product of haemoglobin from red blood cells. Hepatic lipidosis in cats, cholangitis/cholangiohepatitis, toxic hepatopathy, hepatic neoplasia, and cirrhosis can all produce jaundice by impairing the liver's bilirubin conjugation and excretion pathways. The depth of yellowing is not a reliable guide to severity: a blocked bile duct can cause deep jaundice while the liver still functions reasonably well, and serious liver disease can be present with little or no yellowing.
Biliary Obstruction (Post-hepatic)
Obstruction of the bile ducts, whether from gallstones, gallbladder mucocele, pancreatitis causing compression of the common bile duct, or biliary tumours, prevents conjugated bilirubin from reaching the intestine, causing it to accumulate in the blood. Post-hepatic jaundice may be accompanied by pale or acholic (clay-coloured) stools due to the absence of bile pigments in the intestine, and dark-coloured urine from renal excretion of conjugated bilirubin.
Haemolytic (Pre-hepatic)
Accelerated destruction of red blood cells releases bilirubin faster than the liver can process it, producing jaundice from bilirubin overload rather than liver dysfunction. Immune-mediated haemolytic anaemia, blood parasites (such as Mycoplasma haemofelis in cats, and Babesia canis in dogs, which is mostly seen after travel abroad but has been acquired locally in parts of southern England), zinc toxicity, and certain infections can produce haemolytic jaundice. This form is often accompanied by anaemia, weakness, and sometimes dark-coloured urine from haemoglobin excretion.
Infectious
Certain infections have a predilection for affecting the liver or biliary system. Feline infectious peritonitis (FIP) can produce jaundice in cats, particularly the form with fluid build-up. This does not necessarily mean the liver itself is damaged, as widespread inflammation can disturb how bilirubin is handled and red cells may break down. Leptospirosis in dogs can cause both hepatic and renal damage with associated jaundice. It is carried in the urine of rats and other infected animals, and it is zoonotic: people can be infected through contact with an infected dog's urine via broken skin or the eyes, nose or mouth. Bacterial cholangitis and hepatic abscesses can produce jaundice through direct hepatocellular damage and biliary inflammation.
Toxic
Various toxins and medications can cause hepatocellular damage leading to jaundice. In cats, paracetamol causes poisoning at much lower doses than in dogs, damaging red blood cells and the liver. Certain plants, mushrooms, and chemicals can damage the liver sufficiently to impair bilirubin processing. Drug-induced hepatotoxicity from medications metabolised by the liver represents another potential cause.
Why timing matters
Early observation
Early jaundice may be subtle and easily missed, presenting as a faint yellowish tinge to the whites of the eyes (scleral icterus) or the inner surface of the ear pinnae. In animals with dark pigmentation, early jaundice may only be detectable on the gums, mucous membranes, or non-pigmented skin areas. The discolouration may initially be noticed only in bright natural light. At this early stage, bilirubin is already well above normal, though lower than it may later become, and the animal may show few other signs, or may have non-specific signs such as mild appetite reduction or lethargy.
Later presentation
As bilirubin levels rise further, the jaundice becomes more obvious and widespread, with visible yellowing of the skin and mucous membranes, most easily seen on the inner ear flaps and the hairless skin of the belly. The urine may become noticeably darker as the kidneys excrete excess bilirubin. At this stage, the animal typically shows more pronounced signs of illness including significant appetite loss, lethargy, and possibly vomiting or diarrhoea depending on the underlying cause. Advanced jaundice may be accompanied by signs of hepatic encephalopathy if the liver's detoxification capacity is severely compromised.
The trajectory of jaundice depends on its cause. Haemolytic jaundice may develop rapidly over hours to days as red blood cell destruction accelerates. Hepatic jaundice from conditions like hepatic lipidosis may develop over days to weeks as liver function progressively declines. Obstructive jaundice may develop gradually or acutely depending on whether the biliary obstruction is partial or complete. The depth of yellowing is a poor guide to danger. An animal with rapid red cell destruction can be only faintly yellow while its red cell count falls to life-threatening levels. In a cat that has stopped eating and developed hepatic lipidosis, nutritional support, usually through a feeding tube, is central to treatment, and published survival in treated cats is roughly 60 to 80 per cent. Whether bilirubin is rising or settling, and how anaemic the animal has become, cannot be judged by eye and needs blood tests.
Conditions commonly associated
Hepatic Lipidosis in Cats
Hepatic lipidosis in cats often presents with jaundice as bilirubin accumulates due to impaired liver function from fat infiltration.
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Immune-Mediated Haemolytic Anaemia (IMHA)
Jaundice develops in IMHA when the massive breakdown of red blood cells produces bilirubin faster than the liver can process and excrete it, leading to accumulation and visible yellowing of tissues.
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Liver Disease in Dogs
Jaundice can be one of the more recognisable signs of significant liver disease, developing when the liver's ability to process bilirubin is compromised.
Feline Infectious Peritonitis (FIP)
Jaundice in FIP, seen most often in the form with fluid build-up, is not necessarily a sign of direct damage to the liver. It is thought to reflect widespread inflammation interfering with how the liver handles bilirubin, sometimes with red cell breakdown.
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Triaditis in Cats
Jaundice in triaditis reflects liver involvement, specifically cholangiohepatitis, which affects bile processing.
Gallbladder Mucocele
Obstruction of bile flow causes bilirubin accumulation and visible yellowing.
Cholangiocarcinoma
A tumour arising in the bile ducts can block the normal flow of bile, causing a yellow tinge to develop in the skin, gums and eyes.
Acute Hepatic Failure
When the liver fails suddenly, it can no longer process bilirubin properly, giving the skin, gums and eyes a yellow tinge.
Babesiosis
Breakdown of large numbers of red blood cells releases bilirubin faster than the liver can clear it, tinting the eyes and skin yellow.
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Bile Duct Obstruction
When bile can no longer drain from the liver, pigment backs up into the bloodstream and tints the eyes and skin yellow.
Bile Peritonitis
Where bile peritonitis follows a blocked or damaged bile duct, pigment building up in the bloodstream can tinge the skin, gums and eye whites yellow.
Cholangiohepatitis in Cats
Inflammation and blockage within the bile ducts can raise bilirubin levels, giving the gums, skin and whites of the eyes a yellow tinge.
Cholelithiasis
A stone lodged in the common bile duct can block bile flow from the liver and cause bilirubin to build up, producing a yellow tinge to the gums, skin or eyes.
Chronic Hepatitis in Dogs
As functioning liver tissue is progressively lost, bilirubin can no longer be cleared efficiently, giving a yellow tinge to the gums, skin or eyes.
Cirrhosis in Dogs
Scarred, poorly functioning liver tissue can no longer clear bilirubin properly, giving the gums, skin or eyes a yellow tinge.
Copper-Associated Hepatopathy
As copper-related liver damage progresses, bilirubin clearance falls behind, giving a yellow tinge to the gums, skin or eyes.
Hepatic Lipidosis in Dogs
A yellow tinge to the skin, gums or eyes reflects the liver's reduced ability to process bilirubin once it becomes overloaded with fat.
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Paracetamol Toxicity in Cats
Paracetamol damages red blood cells and the liver in cats, and yellowing of the skin and eyes can follow.
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Xylitol Toxicity in Dogs
Larger xylitol ingestions can damage the liver over the following day or two, and yellowing of the skin or eyes reflects that developing liver injury.
Leptospirosis
Leptospirosis can damage the liver and kidneys together, producing jaundice alongside vomiting and changes in urination.
Pancreatitis in Dogs
Inflammation and swelling of the pancreas can compress the common bile duct where it passes nearby, obstructing bile flow and causing jaundice.
Pancreatitis in Cats
Pancreatitis in cats can obstruct the common bile duct and often occurs alongside cholangitis, and either route can produce jaundice.
When to explore further
Any visible jaundice, meaning yellowing of the eyes, gums, skin, or ear pinnae, represents a significant finding that warrants investigation, as it indicates bilirubin levels substantially above normal.
Jaundice developing in a cat that has had reduced appetite or has not been eating for several days, particularly if the cat is overweight, raises concern for hepatic lipidosis, a condition where the outlook is better when treatment starts early in the illness.
Jaundice accompanied by anaemia, with pale gums, weakness and rapid breathing, may suggest a haemolytic process where red blood cells are being destroyed faster than normal, producing bilirubin overload. In dogs this is commonly immune-mediated haemolytic anaemia, in which up to half of affected dogs die despite treatment, with the greatest risk in the first two weeks and blood clots, particularly in the lungs, a leading cause of death.
Jaundice developing alongside abdominal pain, vomiting, or fever may suggest an acute hepatic or biliary process such as cholangitis, pancreatitis, or biliary obstruction.
Rapidly worsening jaundice over hours to days, particularly if accompanied by deteriorating mental status or abnormal behaviour, may suggest acute hepatic failure or severe haemolysis that is progressing quickly.
Jaundice in a dog with vomiting, reduced or absent urination, or bleeding, particularly after access to rivers, canals or areas with rats, fits the pattern of leptospirosis, which can damage the kidneys and liver together. Vaccination does not cover every strain.
Jaundice in a cat with any possible access to paracetamol may reflect paracetamol poisoning, which injures red blood cells and the liver. Swelling of the face and paws, bluish gums and laboured breathing can appear before any yellowing, and the outlook is good with early treatment but falls sharply with delay.
Jaundice with pale gums in a dog that has travelled abroad, or that has picked up ticks in parts of southern England where Babesia canis has been acquired locally, may reflect babesiosis, in which the parasite destroys red blood cells.
Checking the colour of the whites of the eyes, the inner ear flaps, and the gums in natural daylight provides the most reliable visual assessment of jaundice. Noting the colour of the urine, whether it appears darker than usual, can provide additional information, as bilirubin excretion by the kidneys produces characteristically dark, amber-coloured urine. Red or brown urine can instead reflect haemoglobin released from destroyed red cells. A trace of bilirubin in concentrated urine can be normal in dogs, whereas in cats any bilirubin in the urine is abnormal. None of these checks shows the cause or its severity. Whether red cells are being destroyed, the liver is failing or bile flow is blocked, and how anaemic the animal has become, are established with blood tests and usually abdominal ultrasound, and several of these causes can change within hours to days. Yellow-tinged gums that are also pale, with weakness or fast breathing, point towards the anaemic form. Gloves and handwashing when cleaning up urine from a jaundiced dog reduce the household's exposure to leptospirosis, one of the causes of jaundice in dogs.
Last reviewed: 9 October 2026 · Dr Alastair Greenway MRCVS