Dark vertical lines or streaks under the toenail, especially on the big toe, can be a sign of subungual melanoma, which is a type of acral lentiginous melanoma (ALM). While these marks could be normal (particularly in people with darker skin tones) or caused by an injury, it's important to have any unexplained dark streaks Show Full Answer
Dark vertical lines or streaks under the toenail, especially on the big toe, can be a sign of subungual melanoma, which is a type of acral lentiginous melanoma (ALM). While these marks could be normal (particularly in people with darker skin tones) or caused by an injury, it's important to have any unexplained dark streaks examined by a doctor, especially if you haven't experienced recent trauma to the toe. When checking your toenails for potential melanoma, look for these warning signs:
- Dark streaks that appear without injury
- Changes in existing streaks
- Nail splitting or lifting
- Dark skin surrounding the nail
- Nail damage
- Pain, bleeding, or discomfort
Since nail melanomas are often diagnosed at more advanced stages, it's crucial to have any suspicious changes evaluated by a healthcare provider promptly. Regular self-examinations of both your skin and nails in good lighting can help with early detection.
May 8, 2025