Andy Sullivan, age 13, of Cleveland, Ohio, for his question:

HOW DOES A PERSON DEVELOP JAUNDICE?

Jaundice is a yellowish discoloration of the skin, the tissues  and the whites of the eyes. It results from an increased amount of bilirubin, a reddish yellow pigment that is found in the blood.

Bilirubin is formed by the breakdown of hemoglobin, a pigment in red blood cells. The liver removes bilirubin from the blood stream and secretes it in the bile. Thus, jaundice results from either execessive production of bilirubin or reduced secretion of bile.

Jaundice is not a disease but a symptom of various diseases.

Hemolytic jaundice results from an increased breakdown of red blood cells, which causes a greater concentration of bilirubin in the blood.

Hepatocellular jaundice occurs when the liver is damaged so that it cannot secrete enough bile. Bilirubin collects in the body, causing jaundice.

Obstructive jaundice is caused by the blocking of the bile ducts. Gallstones may cause such a blockage.

Many babies are born with physiologic jaundice, which occurs if the body cannot process all the bilirubin it produces. In most cases, this condition disappears by the time the baby is two weeks old.