Slide show: 7 fingernail problems not to ignore

Your fingernails can provide clues to your overall health — but do you know how to read the signs? Check out photos of seven nail conditions that warrant medical attention.

Nail pitting is small depressions in the nails. Nail pitting is most common in people who have psoriasis — a condition characterized by scaly patches on the skin. Nail pitting can also be related to connective tissue disorders, such as Reiter's syndrome, and alopecia areata — an autoimmune disease that causes hair loss.

Nail clubbing occurs when the tips of the fingers enlarge and the nails curve around the fingertips, usually over the course of years. Nail clubbing is sometimes the result of low oxygen in the blood and could be a sign of various types of lung disease. Nail clubbing is also associated with inflammatory bowel disease, cardiovascular disease, liver disease and AIDS.

Spoon nails (koilonychia) are soft nails that look scooped out. The depression usually is large enough to hold a drop of liquid. Often, spoon nails are a sign of iron deficiency anemia or a liver condition known as hemochromatosis, in which your body absorbs too much iron from the food you eat. Spoon nails can also be associated with heart disease and hypothyroidism.

With the condition known as Terry's nails, the tip of each nail has a dark band. Sometimes this can be attributed to aging. In other cases, it can be a sign of a serious underlying condition, such as liver disease, congestive heart failure or diabetes.

Beau's lines are indentations that run across the nails. The indentations can appear when growth at the area under the cuticle is interrupted by injury or severe illness. Conditions associated with Beau's lines include uncontrolled diabetes and peripheral vascular disease, as well as illnesses associated with a high fever, such as scarlet fever, measles, mumps and pneumonia. Beau's lines can also be a sign of zinc deficiency.

With a condition known as onycholysis, the fingernails become loose and can separate from the nail bed. Sometimes detached nails are associated with injury or infection. In other cases nail separation is a reaction to a particular drug or consumer product, such as nail hardeners or adhesives. Thyroid disease and psoriasis — a condition characterized by scaly patches on the skin — also can cause nail separation.

With yellow nail syndrome, nails thicken and new growth slows. This results in a yellowish discoloration of the nails. Nails affected by yellow nail syndrome might lack a cuticle and detach from the nail bed in places. Yellow nail syndrome is often a sign of respiratory disease, such as chronic bronchitis. Yellow nail syndrome can also be related to swelling of the hands (lymphedema).