Black vertical lines on the fingernails may be caused by onychomatous nevus, melanoma, onychomycosis, or subnail hemorrhage.
1. Onychomatous nevus: belongs to pigmented nevus, is a benign tumor growing in the area of nail matrix, which will lead to the appearance of dark brown or black vertical lines on the nail plate, and the border is clear, without pain or itching.
2. Melanoma: it is a kind of malignant tumor that grows under the nail, most of them are irregular in color and shape, with uneven concentration of melanin, and may become bigger or change in color in a short time.
3. Onychomycosis: It is a disease caused by fungus invading the nail plate and the tissues underneath the nail, which may cause nail color changes, brittle nails, thickening, and brown or black color, resulting in black lines.
4. subnail bleeding: for example, localized bruising caused by external pressure, smashing and other factors may also lead to black vertical lines on the fingernail.
Black vertical lines on the fingernail, there may be other reasons, you need to go to the hospital in time to check, follow the doctor’s instructions for treatment.