14. Black Spots and Stripes
Image source: theworld-aroundus.com
While white spots indicate injury, dark lines or spots usually mean that you have an underlying medical condition. There usually isn’t any pain associated with these dark spots, so they’re often ignored. Dark lines can indicate that your body is producing too much melanin or that you have a fungal infection under the nail. If you see these spots or stripes on your nail, get it checked out because it could mean that you have psoriasis or even an aggressive skin cancer called melanoma.