"Why Does the Entire Skin Turn Yellow in Some Individuals?"
Although our skin is yellow, numerous diseases can also lead to abnormal yellowing of the skin. This is particularly common among newborns, who often experience yellowing of their entire body, primarily caused by diseases affecting the liver, gallbladder, pancreas, and especially jaundice-type hepatitis. This can significantly discolor a child's skin, and in severe cases, may result in liver dysfunction and abnormal bilirubin metabolism.
Primary Diagnostic Criteria for Jaundice
Jaundice is merely a symptom/sign, not a disease. While diagnosing jaundice is straightforward, differential diagnosis is crucial. When serum bilirubin concentrations range from 17.1 to 34.2umol/L (1–2mg/dl), yet jaundice is not visibly discernible by the naked eye, it is termed occult jaundice. When serum bilirubin concentrations exceed 34.2umol/L (2mg/dl), overt jaundice manifests as yellow staining of the sclera, skin, mucous membranes, and other tissues and bodily fluids.
Differential diagnosis of jaundice-related diseases necessitates differentiation from pseudojaundice, which occurs due to excessive consumption of foods rich in carotenoids, such as carrots, pumpkins, tomatoes, and citrus fruits. Carotenoids cause yellowing of the skin but not the sclera. Elderly individuals may exhibit slight yellow fatty deposits in the bulbar conjunctiva, with uneven scleral yellowing more pronounced at the inner canthus, yet without skin yellowing. Blood bilirubin levels remain normal in pseudojaundice.
Primary Treatment Approaches for Jaundice
The treatment principle for jaundice involves addressing the underlying etiology while managing symptoms such as itching and reducing jaundice. When jaundice occurs, it is essential to check serum total bilirubin and direct bilirubin levels to distinguish the type of bilirubin elevation. Additionally, examining urine bilirubin, urobilinogen, and liver function is indispensable.
Elevated Indirect Bilirubin: Predominantly seen in various hemolytic disorders and neonatal jaundice. The ratio of direct to total bilirubin is less than 35%. Besides the aforementioned tests, additional assessments for hemolytic disorders, such as erythrocyte fragility tests, acid hemolysis tests, autohemolysis tests, anti-human globulin tests, blood routine, urine occult blood, serum free hemoglobin, urine hemosiderin, serum lactate dehydrogenase, and glucose-6-phosphate dehydrogenase, are necessary.
Elevated Direct Bilirubin: Found in various intrahepatic and extrahepatic obstructions impeding bile excretion, with a direct-to-total bilirubin ratio exceeding 55%. Besides routine examinations, further tests like alkaline phosphatase, γ-glutamyl transpeptidase, leucine aminopeptidase, 5'-nucleotidase, total cholesterol, and lipoprotein-X are required.
Mixed Jaundice Due to Hepatocellular Injury: Observed in various liver diseases, characterized by elevated levels of both direct and indirect bilirubin, with a direct-to-total bilirubin ratio ranging from 35% to 55%. Abnormal results are obtained upon liver function tests.
