How did I get it?
Repetitive and prolonged wetting and drying of the fingernails is the single most common cause of splitting and ridging of the nails. Splitting of the nails is rarely caused by internal disease or vitamin deficiency. Nail polish remover causes onychoschizia. Trauma to the fingers contributes to onychoschizia.

How do I treat it?
The best treatment is to avoid repeated wetting and drying of the nails. Try to wear cotton lined rubber gloves when performing household chores that involve getting the hands wet. Rub lotions containing alpha-hydroxy acids such as MD Forte or lanolin-containing lotions such as Elon into the nails both before and after getting the hands wet. Watch people who have beautiful nails. Notice how they use their hands or finger pads to do simple chores rather than use their nails. Never dial a phone with the nail tips; use a pencil. Nails should never be used as tools. Get in the habit of using your fingers as if they have wet polish on them. If you can't avoid trauma to the nail tips, keep the nails cut short.