The statement “If you have these lines on your nails, you should pay attention” is partly true, but it depends entirely on what kind of lines are being discussed. Many nail lines are harmless, while some can be a reason to seek medical advice.
Common nail lines that are usually harmless
Vertical ridges (running from the cuticle to the tip):
- Very common, especially with age
- Usually not a sign of disease
- Similar to wrinkles developing in the skin
Nail lines that may deserve attention
Horizontal grooves (Beau’s lines)
- Can appear after a severe illness, high fever, major stress, injury to the nail, or certain medical conditions
- They represent a temporary interruption in nail growth
Dark brown or black streaks
- Often harmless, especially in people with naturally darker skin tones
- However, a new, widening, irregular dark streak in a single nail should be evaluated because it can rarely be associated with a serious form of skin cancer under the nail
White lines or bands
- Can have several causes, including nail injury
- Less commonly associated with nutritional deficiencies or medical conditions
When to see a healthcare professional
Consider getting a nail change checked if:
- It is new and persistent
- It affects only one nail and is worsening
- There is pain, bleeding, nail destruction, or pigment spreading onto the surrounding skin
- It is accompanied by other symptoms such as weight loss, fatigue, or significant illness
Bottom line
Most nail lines—especially vertical ridges—are a normal part of aging and not a cause for concern. The important thing is to watch for new, changing, or unusual lines, particularly dark streaks or deep horizontal grooves.
If you can describe the lines (vertical, horizontal, white, black, ridged, etc.) or share a photo, I can explain what they are most commonly associated with.
