Skin discoloration can be upsetting if you don't understand what caused it. Even if the cause is benign or quick to remedy, a yellow color is an indicator that a process or substance in your body may be overloading your system in some way. A number of conditions can result in your skin turning yellow, and if this is happening to you, talk to your doctor to determine the cause.
Jaundice
Jaundice is an umbrella term that covers yellow skin due to excess bilirubin. The exact causes of jaundice are many. Bilirubin is the collection of old red blood cells that have been processed by the liver. The University of Maryland Medical Center says an excess of bilirubin can build up if the liver is diseased, damaged or overwhelmed by an excessively large amount of red blood cells "retiring," or if there are problems with the biliary duct, along which bilirubin usually moves into the gut. The bilirubin that can't escape the body starts to show through the skin as a yellow pigment. Sometimes jaundice is either normal or expected. Newborns may be jaundiced for their first week as their system recuperates after birth, and bruises often turn a yellow hue when healing. Other causes are more alarming; hepatitis, malaria, hemolytic anemia, pancreatic cancer and other liver diseases, such as cirrhosis, can lead to jaundice.
Hypercarotenemia
A seemingly alarming but usually harmless condition is hypercarotenemia, also called carotenemia and carotenodermia. This is a buildup of beta carotene in your tissue and is usually due to eating too much beta-carotene-rich food, such as carrots, squash, sweet potatoes, oranges and spinach. The condition leads to your skin, especially your palms and the soles on your feet, turning a shade somewhere between yellow and orange. Columbia University's Health Services department says that eating as little as three 8-inch carrots daily, for an intake of over 20mg of beta carotene, is enough to set off hypercarotenemia. Hypercarotenemia can sometimes be an indicator of anorexia nervosa. Patrick Yao, a doctor with the UCLA Department of Medicine, writes in a 2007 case report that this may be partly due the person eating high-carotene foods for most of their diet, or due to a metabolic defect.
Yellow Nails
If the yellow color is limited to your fingernails, something has slowed down the growth of the nails. The Mayo Clinic says common reasons for this include respiratory disorders or lymphedema, a condition that includes swelling in the hands. Yellow nail syndrome, as it's called, may lead to the disappearance of the nail's cuticle and to the nail detaching from the skin underneath.
TNT Poisoning
The explosive trinitrotoluene, or TNT, presents risks of not only exploding and injuring those around, but of poisoning whoever is handling it. A 2008 paper in the journal The Chemical Educator notes that munitions workers in Britain during World War I fell prey to TNT poisoning after long hours of manufacturing bullets and other explosives for soldiers. One of the initial symptoms was yellow skin on the hands--the female workers were sometimes called "Canary Girls"--due to "nitro groups" within the TNT that reacted with melanin in the workers' skin.
