The most common disorder of the human fingernail is fungal infection, notes WebMD. Flaking, cracking or discoloration of the nails of both fingers and toes may indicate a problem with the nail itself or the presence of other health conditions impacting the health of the nail and the nail bed.
In addition to medical disorders affecting the nails, nail biting, injury and the application of false nails cause damage, according to Everyday Health. Nails are often injured, ripped or torn. Treatment for torn or separated nails may include removal of the nail itself. New nails grow slowly in place of nails that are removed as part of treatment of an injury.