Your toenails and fingernails protect the tissues of your toes and fingers. They are made up of layers of a hardened protein called keratin, which is also in your hair and skin. The health of your nails can be a clue to your overall health. Healthy nails are usually smooth and consistent in color. Specific types of nail discoloration and changes in growth rate can be signs of lung, heart, kidney, and liver diseases, as well as diabetes and anemia.

Many disorders can affect the nails, including bacterial and fungal infections, deformities, dystrophies, infections, and ingrown toenails.

Some of the causes of nail disorders include the following:

Infections (such as paronychia, warts, and green nail syndrome). Infections can involve any part of the nail and may or may not change the nail's appearance.

Injuries. Severe damage to the nail bed (the soft tissue underneath the nail plate that attaches the nail to the finger), particularly from a crush injury, often results in permanent nail deformity. To reduce the risk of a permanent nail deformity, the injury should be repaired immediately, which requires removal of the nail.

Internal diseases (such as certain lung diseases, which can cause yellow nail syndrome). For example, iron deficiency may cause spoon-shaped nails (koilonychia), kidney failure may cause the bottom half of the nails to turn white and the top half of the nails to turn pink or appear pigmented (half-and-half nails), cirrhosis may cause the nails to turn white, although the very top part of the nails may remain pinker (Terry nails), low blood levels of the protein albumin (which may occur in people with cirrhosis) can cause horizontal white lines to form on the nails etc.

Structural problems (such as an ingrown toenail).

An ingrown nail can result when a deformed toenail grows improperly into the skin or when the skin around the nail grows abnormally fast and engulfs part of the nail. Wearing narrow, ill-fitting shoes and trimming the nail into a curve with short edges rather than straight across can cause or worsen ingrown toenails.

Ingrown nails may produce no symptoms at first but eventually may become painful, especially when pressure is applied to the ingrown area. The area is usually red and may be warm. If not treated, the area is prone to infection. Once infected, the area becomes more painful, red, and swollen. Pus may accumulate under the skin next to the nail (an infection of the cuticle called paronychia) and drain.

Birth deformities and changes in nail shape. Some babies are born without nails (anonychia). ). In nail-patella syndrome thumbnails are missing or are small with pitting and ridges. Darier disease causes red and white streaks on the nails and V-shaped notches to form on the tips of the nails. In pachyonychia congenita, nail beds (the parts of the nail unit that attach the nail to the finger) are thickened and discolored and are curved from side to side, forming a pincer nail deformity.

Nail dystrophies - changes in nail texture. About 50% of nail dystrophies are caused by a fungal infection. The remainder result from various causes, including injuries, birth deformities, psoriasis, lichen planus, and occasionally cancer. Drugs, infections, and diseases can cause discoloration of the nails (chromonychia).

Drugs - different drugs lead to discoloration of the nail, which usually gets better after the drug is stopped and the nail grows out.

Tumors. Noncancerous (benign) and cancerous (malignant) tumors can affect the nail unit, causing a dystrophy. When doctors suspect cancer, they do a biopsy and may recommend complete removal of the tumor as soon as possible.

Treatment for nail diseases may include oral or topical medications. The nail may need to be removed for severe infections.

Tips for healthy nails

Nails reflect our overall health, which is why proper nail care is so important. Here are dermatologists’ tips for keeping your nails healthy:

Keep nails clean and dry.
Cut nails straight across. Use sharp nail scissors or clippers. Round the nails slightly at the tips for maximum strength.
Keep nails shaped and free of snags by filing with an emery board.
Do not bite fingernails or remove the cuticle. Doing so can damage the nail.
Do not use your nails as a tool, such as opening pop cans.
Trim toenails regularly. Keeping them short will minimize the risk of trauma and injury.
When toenails are thick and difficult to cut, soak your feet in warm salt water. Mix one teaspoon of salt per pint of water and soak for 5 to 10 minutes.
Avoid “digging out” ingrown toenails, especially if they are infected and sore. If you are suffering from an ingrown toenail, see a dermatologist for treatment.
Wear shoes that fit properly. Also alternate which pair of shoes you wear each day.
Wear flip flops at the pool and in public showers. This reduces the risk of infections caused by a fungus that can get in your toenails.

If your nails change, swell, or cause pain, see your dermatologist because these can be signs of serious nail problems. If you have diabetes or poor circulation, it’s especially important to seek treatment for any nail problems. If you have questions or concerns about caring for your nails, see a dermatologist.