Diseases of the liver such as various types of hepatitis, cirrhosis and biliary stasis can often lead to the appearance of jaundice, the main manifestation of which is yellowing of the skin and sclera.
As the nail plate is translucent, the colour of the skin can show through the nail plate and take on a hue consistent with the rest of the skin. Therefore, if there is yellowing of the skin all over the body, including the nail, and yellowing of the sclera, liver disease should be considered first.
However, if only the nail plate is yellow, systemic factors such as carotenemia, yellow nail syndrome and drug effects should be looked for. Whereas if only part of the nail turns yellow, or part of the nail turns yellow, look for local factors such as contamination with coloured substances, skin disease or tumours.