The sclera, the typically white outer layer of the eyeball, provides structural support and protection. When this part of the eye takes on a yellowish hue, it indicates an underlying change in the body’s chemistry. This discoloration is not a condition in itself, but rather a visible symptom signaling that medical attention may be helpful.
Understanding Jaundice
The medical term for the yellowing of the skin and eyes is jaundice, also known as icterus. This yellow discoloration occurs due to an excess of bilirubin, a yellowish pigment, circulating in the bloodstream. Bilirubin forms primarily from the natural breakdown of old red blood cells in the body, particularly from the heme component of hemoglobin. Approximately 80% of bilirubin originates from this process, with the remainder coming from the turnover of other heme-containing proteins.
Normally, bilirubin travels through the bloodstream, bound to a protein called albumin, to the liver. In the liver, it undergoes a transformation where it is made water-soluble, a process known as conjugation. This conjugated bilirubin then mixes with bile, a digestive fluid, and is transported into the digestive system, eventually being excreted from the body primarily in stool. Yellow sclera develops when this normal pathway is disrupted, leading to a buildup of bilirubin in the blood and its deposition in tissues, including the eyes.
Common Causes of Yellow Sclera
Yellow sclera often points to issues affecting the liver, bile ducts, or red blood cell breakdown. Liver conditions, such as hepatitis, impair the liver’s ability to process bilirubin effectively. Hepatitis, whether viral (like hepatitis A, B, or C), alcoholic, or autoimmune, causes inflammation and damage to liver cells, hindering their capacity to conjugate and excrete bilirubin. Cirrhosis, a late-stage scarring of the liver often resulting from chronic liver diseases, similarly reduces the liver’s filtering capability, leading to bilirubin accumulation. Fatty liver disease can also interfere with liver function, contributing to this buildup.
Obstruction of the bile ducts prevents conjugated bilirubin from being excreted from the liver into the intestines. Common culprits include gallstones, which are hardened deposits, or tumors in the pancreas or bile ducts. When these ducts are blocked, bile backs up into the liver and subsequently into the bloodstream, causing jaundice.
Blood disorders involving excessive red blood cell destruction can overwhelm the liver’s capacity to process bilirubin. Conditions like hemolytic anemia cause red blood cells to break down rapidly, leading to an overload of unconjugated bilirubin. Sickle cell anemia, for instance, is a type of hemolytic anemia that results in increased bilirubin production. Even a healthy liver may struggle to keep up with this rapid influx.
Less common causes of yellow sclera include certain medications and genetic syndromes. Some drugs, such as high doses of acetaminophen, penicillin, oral contraceptives, chlorpromazine, and anabolic steroids, can induce liver injury or affect bilirubin metabolism. Gilbert’s syndrome, a benign genetic condition, involves a slightly reduced ability of the liver to process bilirubin, leading to mild, fluctuating yellowing of the eyes, especially during periods of stress, fasting, or illness. This syndrome typically does not require specific treatment.
Accompanying Symptoms and When to Seek Medical Attention
Yellow sclera frequently appears alongside other symptoms, providing further clues about the underlying cause. Dark urine, often described as tea-colored, occurs when excess bilirubin is filtered by the kidneys and excreted. Conversely, stools may become pale or clay-colored if bilirubin is prevented from reaching the intestines due to a bile duct obstruction. Generalized itching, known as pruritus, is another common symptom resulting from bilirubin buildup in the skin.
Other symptoms that might accompany yellow eyes include fatigue, nausea, vomiting, and abdominal pain. Unexplained weight loss and fever can also be present, especially if the underlying cause is an infection or a more severe condition. Any instance of yellowing in the sclera warrants medical evaluation, as it signals that a bodily system is not functioning as it should.
Seeking prompt medical attention is important if yellow sclera appears suddenly or is accompanied by severe symptoms. These “red flag” symptoms include severe abdominal pain, confusion, or a high fever, as they may indicate a rapidly progressing or serious condition. Early diagnosis and treatment of the underlying cause are important to prevent potential complications.
Diagnostic Process and Management
When seeking medical help for yellow sclera, a healthcare provider begins with a comprehensive medical history and physical examination. The medical history includes questions about the duration of yellowing, other symptoms, alcohol consumption, medication use, and any family history of liver or blood disorders. A physical examination assesses for signs of liver enlargement, tenderness, or other physical manifestations of underlying conditions.
To determine the cause, various diagnostic tests are ordered. Blood tests include measuring total and fractionated bilirubin levels to distinguish between unconjugated and conjugated bilirubin dominance. Liver function tests (LFTs) assess liver health and function, while a complete blood count (CBC) can indicate issues like hemolytic anemia. Imaging studies, such as an abdominal ultrasound, CT scan, or MRI, help visualize the liver, gallbladder, and bile ducts to identify structural abnormalities like blockages or tumors. In some cases, a liver biopsy may be necessary for a definitive diagnosis.
Management of yellow sclera depends on identifying and treating the underlying cause. There is no specific treatment for the yellow discoloration itself; it resolves once the primary condition is addressed. For example, viral hepatitis might be managed with antiviral medications, while gallstones causing a blockage may require surgical removal. Blood disorders like hemolytic anemia are managed by addressing abnormal red blood cell breakdown. The prognosis for individuals with yellow sclera varies widely, depending on the severity and nature of the underlying condition.