14. Black Spots And Stripes
Dark lines or black spots that are not attained by physical injuries can be a sign of several medical conditions. They don’t cause any pain or discomfort so that is why many people seem to ignore them. Dark colored lines are caused by an overproduction of melanin, but if that’s not the case it is probably caused by fungus underneath the nail. It is very important to visit your doctor because darkened nails are also an indication of more serious health conditions, such as psoriasis and melanoma, which is an aggressive form of skin cancer that attacks the nail bed.