Nail changes may signify a number of disorders elsewhere in the body.   These changes may indicate illness even before the rest of the body does.   Seek medical attention if any of the following symptoms are suspected.

Symptoms:

• Thick nails may indicate that the vascular system is weakening and the blood is not circulating properly.
• Lengthwise grooves or ridges may indicate a kidney disorder and is associated with aging. An iron deficiency may also cause ridges.
• If the white moon area of the nail turns red, it may indicate heart problems; if it turns slate blue, than it indicates overexposure to silver or lung trouble.
• Flat nails can denote Raynaud's disease.
• Brittle nails signify possible iron deficiency and thyroid problems, impaired kidney functions, and circulation problems.
• Yellow nails can indicate internal disorders long before other symptoms appear. Some of these are problems with the lymphatic system, respiratory disorders, diabetes, and liver disorders.
• Dark nails and/or thin, flat, spoon-shaped nails are a sign of vitamin B12 deficiency or anemia.
• Deep blue nail beds show pulmonary obstruction such as asthma or emphysema.
• White nails with pink near the tips are a sign of cirrhosis.
• Nail beading is a sign of rheumatoid arthritis.
• Pitted red-brown spots and frayed and split ends indicate psoriasis; vitamin C, folic acid, and protein are needed.
• Nails that chip, peel, crack, or break easily show a nutritional deficiency and insufficient hydrochloric acid and protein.  Minerals are also needed.
• Brittle, soft, shiny nails without a moon may indicate an overactive thyroid.
• White lines across the nail may indicate a liver disease.
• Thinning nails may signal an itchy skin disease.
• Nails separated from the nail bed may signify a thyroid disorder.
• A half white nail with dark spots on the tip points out a possible kidney.
• Raised nails at the base with small white ends show a respiratory disorder such as emphysema or chronic bronchitis.  This nail condition may also be hereditary.
• Red skin at the bottom of the nail may indicate a connective tissue disorder.
• Ridges can signify a possible infection such as the flu.
• Downward curved nail ends may denote heart, liver, or respiratory problems.
• White lines show possible heart disease, high fever, or arsenic poisoning.
• Ridges running up and down indicate a tendency to develop arthritis.
• Nails that resemble hammered brass indicate a tendency to total hair loss.