Leukonychia is caused by bubbles of air that become trapped underneath the fingernail.
Leukonychia can also look like wavy horizontal lines across the nails, or sometimes it shows up in various patterns and shapes.
Often times white nail marks may occur due to a minor injury at the base of the nail.
It's said they also sometimes developed because of hereditary reasons, but in other cases they may indicate a medical issue such a fungal infection or vitamin deficiency.
Consuming adequate protein has been found to rebuild damaged fingernails, and zinc prevents the spots from forming in the first instance. As a preventative, make sure you're getting the optimal daily amount of zinc and protein in your diet.
Leukonychia may indicate a more serious medical issue such as an organ failure, so it's always helpful to question your doctor during your regular routine office visit.