Melanoma, the deadliest form of skin cancer, can grow under the nail in rare cases causing a dark-colored streak that appears at the base of nail. These melanomas may be mistaken for injuries, however, a dermatologist should be consulted if the discoloration does not gradually improve or if the size of the streak increases. With early detection, melanoma has a very high cure rate.
Dark bands or streaks in African-American fingernails and toe nails are normal. These tend to increase with age and are usually not an indication of melanoma or other disease. However, you should consult a dermatologist about any nail discoloration that grows or seems suspicious.
The board-certified dermatologist at Dermatology & Skin Surgery are highly-trained specialists who can find the cause of nail discoloration and providing appropriate treatment when necessary.