The color of your fingernails isn’t likely the first thing that comes to mind when you think about your health, but yellow fingernails and yellow toenails have the potential to indicate some deeper heath troubles. Although it’s not always the case, the following conditions can cause discoloration.
http://www.doctorshealthpress.com/general-health-articles/yellow-fingernails/
White or Pale Fingernails. 1  May be indicative of kidney or liver disorders or anemia. 2  White lined bands across the nail beds can signal a protein deficiency. 3  White nails with a rim of darker color at the tip of the nail is called Terry's nail and can be a sign of cirrhosis of the liver.
https://www.disabled-world.com/health/dermatology/nails/nail-color.php
Separation of the nails from the nail bed (onycholysis) may cause the nails to fall out. Some individuals may develop infection of the soft tissue around edge of the nails (paronychia). Any nail (both toenails and fingernails) may be affected. Unlike the nails in similar, related disorders, the nails of individuals with yellow nail syndrome generally remain clear (translucent) and smooth as opposed to not transparent (opaque) and rough.
https://rarediseases.org/rare-diseases/yellow-nail-syndrome/
Healthy fingernails and toenails should generally be a pink color - with the healthy nail plate being pink, and the nail being white in color as it grows off the nail bed. Fingernail color and condition changes are rarely the first clue of serious illness.
https://www.disabled-world.com/health/dermatology/nails/nail-color.php
How to Get Rid of Yellow Fingernails. 1. Lemon. Lemon is a natural bleaching agent that can remove yellow stains from your nails. Lemon is a natural bleaching agent that can remove yellow stains from your nails. It also acts as an astringent, which can offer healing for the pores and the area underneath the nail.
http://www.doctorshealthpress.com/general-health-articles/yellow-fingernails/
Causes of yellow nails. If your nails have turned yellow and you haven’t painted them that color or injured them, most often it’s because you’ve picked up an infection. Usually the culprit is a fungus. In rare cases, the color change can stem from a condition called yellow nail syndrome.
http://www.healthline.com/health/is-diabetes-causing-my-yellow-nails
Causes of Yellow Nails. Fungal Infections. Yellow nails are most commonly the result of a fungal infection, which makes plenty of sense as your hands and feet come into contact with all kinds of potentially infectious bacteria; your toes in particular are exposed to moist, warm temperatures where fungus can fester.
http://www.doctorshealthpress.com/general-health-articles/yellow-fingernails/
Yellow nail syndrome is an extremely rare disorder characterized by malformations affecting the fingernails and toenails, abnormalities affecting the lungs and the airways (respiratory tract), and swelling or puffiness in different parts of the body because of the accumulation of protein-rich fluid (lymph) in the soft layers of tissue under the skin ...
https://rarediseases.org/rare-diseases/yellow-nail-syndrome/
But in certain cases, yellowing can be a sign of a nail infection. People with diabetes are more likely than those without it to get a fungal infection called onychomycosis. This infection usually affects the toenails. The nails will turn yellow and become brittle.
http://www.healthline.com/health/is-diabetes-causing-my-yellow-nails
Definition: Nail (Anatomy) A nail, in anatomy, is defined as a horn-like envelope covering the tips of the fingers and toes in humans, most non-human primates, and a few other mammals. Nails are similar to claws in other animals. Fingernails and toenails are made of a tough protective protein called keratin.
https://www.disabled-world.com/health/dermatology/nails/nail-color.php
what causes yellow fingernails and toenails
One of the most common causes of yellow nails is a fungal infection. The  yellow fingernails and toenails causes Fungal Infections. A fungal infection causes yellow fingernails and toenails. Fungal Infections causes yellow fingernails and toenails.