Your nails may yellow with age or due to the use of acrylic nails or nail polish. Smoking can also stain nails a yellowish hue. If your nails are thick, crumbly, and yellow, a fungal infection could be to blame.
Less often, yellow nails may be related to thyroid disease, diabetes, psoriasis, or respiratory disease (such as chronic bronchitis).
Dry, Cracked or Brittle Nails
Lifestyle factors may play a role here, such as if you have your hands in water a lot (washing dishes, swimming, etc.), use nail polish remover frequently, are exposed to chemicals (such as cleaning products) often, or live in a region with low humidity.
Cracking and splitting can also be caused by a fungal infection or thyroid disease, particularly hypothyroidism. Brittle nails may also be due to a deficiency in vitamins A and C or the B vitamin biotin.
Clubbing describes when your fingertips become enlarged and the nail becomes curved downward. It can be a sign of low oxygen in your blood and is associated with lung disease. Clubbing can also be related to liver or kidney disease, heart disease, inflammatory bowel disease, and AIDS.
Small white spots on your nails are usually the result of nail trauma. They’re not cause for concern and will fade or grow out on their own. Less commonly, white spots that do not go away could be due to a fungal infection.