Yellow Eyes or Skin (Jaundice) in Horses

Key Takeaways

Jaundice, also known as icterus, is yellowing of the skin, gums and whites of the eyes. 

• Horses showing jaundice require prompt veterinary assessment, as causes range from not eating to liver dysfunction or excessive breakdown of red blood cells

• Jaundice in newborn foals indicates a rare, life-threatening blood disorder

• If jaundice is observed, diagnostics include a physical exam, blood testing, urinalysis, diagnostic imaging, and if liver dysfunction is suspected, liver biopsy

• Treatment is dependent on the underlying condition, although rest and IV fluids are often required regardless of the cause

A Closer Look: What is Jaundice in Horses?

Jaundice requires prompt veterinary assessment to determine the underlying cause. Anorexia (lack of appetite) is one of the most common causes of jaundice in horses.  If liver dysfunction is the cause, outcomes are more favorable when treated early. When jaundice is due to anemia, immediate veterinary intervention is necessary.

Possible Causes

Potential causes of jaundice are related to not eating, liver dysfunction, or excessive breakdown of red blood cells.

Causes of jaundice related to liver dysfunction include:

• Alsike clover toxicity • Liver scarring (fibrosis/cirrhosis) • Bile duct obstruction • Tumors/cancer

• Bile duct inflammation (Cholangiohepatitis) • Liver damage caused by not eating (Fasting hyperbilirubinemia) 

• Liver inflammation (Hepatitis) • Liver infection (such as Tyzzer disease)• Poisoning  • Liver failure

• Serum sickness/Theiler’s disease • Liver viruses

Red blood cell-related causes include:

• Red maple toxicity • Immune-mediated hemolytic anemia • Equine infectious anemia

• Neonatal isoerythrolysis

Risk Factors

Yellow skin pigmentation occurs due to the buildup of bilirubin. Bilirubin is a by-product of red blood cells being broken down, and it is normally excreted in the feces or urine.  Jaundice takes time to develop. The waste products that build up in the bloodstream must accumulate over a period of time before a yellow pigment is externally visible. It also takes time for the yellow color to dissipate once the condition is corrected, much like how a bruise fades over several days.

Testing and Diagnosis

Diagnostic procedures to investigate jaundice include:

• Health history • Blood testing • Physical exam • Liver biopsy • Fecal sample analysis • Urinalysis

• Diagnostic imaging • Scintigraphy (study of distribution of radioactive compound injected into the body)

Treatment varies depending on the underlying cause, but may include 

• Sedation if neurological symptoms present threat of injury • IV fluids • Rest • Medications • Dietary management

• Nutriceuticals

Blood transfusion may also be necessary if jaundice is related to a blood condition.

Similar symptoms

Jaundice is unique and self evident. It is not likely to be confused with other symptoms.

Associated Symptoms

Symptoms often observed with jaundice include:

• Weight loss • Weakness • Lethargy • Fever • Abdominal pain (colic) • Diarrhea • Constipation • Abnormal bleeding

• Difficulty breathing • Loss of appetite • Red or brown urine • High-pitched or loud breathing sounds

• Inflammation between hoof and coffin bone (Laminitis) • Enlarged abdomen • Intestinal impaction or obstruction

• Blindness • Sweating • Increased heart rate • Head pressing • Circling • Aimless walking • Lack of coordination

• Pica • Difficulty swallowing • Repetitive yawning • Aggression • Stupor • Seizures • Coma • Itching

• Red skin patches • Skin ulceration • Eye inflammation • Eye discharge • Aversion to light

• Cloudy corneas • UV light sensitivity of the skin (Photosensitization)