One of the most common causes of yellow nails is a fungal infection. As the infection worsens, the nail bed may retract, and nails may thicken and crumble. In rare cases, yellow nails can indicate a more serious condition such as severe thyroid disease, lung disease, diabetes or psoriasis
Nails with a bluish tint can mean the body isn’t getting enough oxygen. This could indicate a lung problem, such as emphysema. Some heart problems can be associated with bluish nails.
If the nail surface is rippled or pitted, this may be an early sign of psoriasis or inflammatory arthritis. Discoloration of the nail is common; the skin under the nail can seem reddish-brown.
Cracked or Split Nails
Dry, brittle nails that frequently crack or split have been linked to thyroid disease. Cracking or splitting combined with a yellowish hue is more likely due to a fungal infection.
If the skin around the nail appears red and puffy, this is known as inflammation of the nail fold. It may be the result of lupus or another connective tissue disorder. Infection can also cause redness and inflammation of the nail fold.
Biting your nails may be nothing more than an old habit, but in some cases it’s a sign of persistent anxiety that could benefit from treatment. Nail biting or picking has also been linked to obsessive-compulsive disorder. If you can’t stop, it’s worth discussing with your doctor.
Though nail changes accompany many conditions, these changes are rarely the first sign. And many nail abnormalities are harmless — not everyone with white nails has hepatitis. If you’re concerned about the appearance of your nails, see your doctor or a dermatologist.