Fungus infections cause less than five percent of deformed nails. Drying of skin and skin conditions such as psoriasis are more common causes.
The part of nails that you see is dead. Living nails are located underneath the skin at their base. It takes four and a half months for the nail to grow from the nail plate to its end where you cut it off. During this time, the nail dries out and the ends can crack and fray. So the most common cause of deformed nails is drying with aging. best treated by coating the nails with nail polish three times a week. The polish delays sublimation of water and helps to prevent drying.
Most deformed nails are caused by skin conditions such as psoriasis or seborrheic dermatitis. If you have thickened toenails, check with a podiatrist or dermatologist who will clip off a piece of the nail and place it in a special bottle to culture it for a fungus. Since a fungus infection in the nail starts in the plate underneath the skin and no creams can get into the nail plate, pills are the most effective treatment for toenail fungus infections. A special laquer called Penlac can cure some fungus nails when applied for several weeks. Fungus infections can usually be cured with two 100 mg itraconazole pills each morning every other week for 4 to 5 months, or by another drug called terbinafine.  Laser is a treatment option, with about a 75 percent success rate (compared to 63 percent with pills). Check with your podiatrist.
If no fungus is present, fungus pills will not help. Gene Mirkin, DPM, offers these tips for care of deformed or infected toenails:
• Keep your nails cut short and file down any thick areas.
• Buy surgical quality nail clippers that are strong enough to cut thickened toenails without tearing them.
• Don’t use the same nail trimmer or file on healthy nails and infected nails. If you have your nails professionally manicured, you should bring your own nail files and trimmers from home.
• Wear 100 percent cotton socks. Change your socks when they are damp from sweat or if your feet get wet. Put on clean, dry socks every day. You can put over-the-counter antifungal foot powder inside your socks to help keep your feet dry.
• Wear shoes with good support and a wide toe area. Don’t wear pointed shoes that press your toes together.
• Avoid walking barefoot in public areas, such as locker rooms.
More on fungus toenails
Contributed by Gene Mirkin, DPM
Checked 4/3/23