Some changes, however, are potentially dangerous, and this is definitely one of them.
Cancerous tissues on the skin, known as melanomas, can develop under the fingernail. It happens more often in people of African descent, but it absolutely can strike anyone at any time.
Found early enough, removal of the nail and the cancerous growth under it is sufficient for solving the problem. Cancer left unchecked can metastasize to other organs which can ultimately result in death.
Dr. Dana Stern, a cancer specialist, talks in the following video about what to look for: