The whites of the eyes yellow, then the mucous membranes, and then the skin generally
When, for various reasons, the liver cannot handle the load placed upon it, bilirubin builds up. This is a yellow-brown substance which results from the breakdown of old red blood cells.
The liver must constantly remove bilirubin from the blood; and, if this is not done, bilirubin begins collecting in tissues all over the body, the urine is darker, and the stools are lighter because the bilirubin it usually contains is not present.
But red blood cell destruction can also cause it. Blood tests identify whether the problem is an obstruction or RBC destruction.
Jaundice is not itself a disease, but rather a symptom of one. It can point to pernicious anemia, hepatitis, cirrhosis of the liver, and hemolysis (which is an abnormal destruction of red blood cells).
Jaundice can also be caused by a blockage of the bile duct system in the liver, because of gallstones or a tumor. More rarely, it is caused by a parasitic infestation, such as tapeworm, hookworm, a flea, or mosquito carrying a viral infection.