If you have lines on your nails, it does not automatically mean you have cancer. Nail changes can happen for many reasons, and most are harmless.
Common types of nail lines and what they may mean:
- Vertical ridges (lines running from the cuticle to the tip)
- Very common, especially with aging.
- Can also be related to dry nails or normal changes in nail growth.
- Horizontal grooves (Beau’s lines)
- Can appear after illness, major stress on the body, injury, or certain medical treatments.
- They happen when nail growth is temporarily interrupted.
- Dark vertical streaks (brown or black lines)
- Often caused by increased pigment, injury, or benign changes.
- Rarely, a new or changing dark streak—especially on one nail—can be a sign of subungual melanoma (a rare nail-area skin cancer).
See a healthcare professional or dermatologist if:
- A dark line appears suddenly or is getting wider/darker
- The pigment spreads onto the surrounding skin near the nail
- The nail is changing shape, cracking, or lifting
- You have unexplained nail changes affecting only one nail
Most nail ridges are not a sign of cancer, but unusual or changing nail markings are worth having checked.
