Red lines on a fingernail can mean different things depending on what they look like. The two most common possibilities are:
🔴 1. Splinter hemorrhages (most common concern)
- Look like tiny red or brown vertical streaks under the nail
- Often caused by small blood vessel damage
- Can happen from:
- Minor trauma (bumping, typing, nail injury)
- Nail picking or manicure pressure
- Usually harmless if it’s just one or a few nails after injury
But if they appear in multiple nails without injury, they can sometimes be linked to medical conditions like:
- Heart infection (rare) → Infective endocarditis
- Blood vessel inflammation
- Certain autoimmune conditions
🔴 2. Beau’s lines (not red, but may look streaked)
- Horizontal grooves or lines across the nail
- Related to temporary growth interruption (illness, stress, fever)
⚠️ When to be more careful
You should get it checked if:
- Red lines appear on many nails
- They keep coming back without injury
- You also have symptoms like fever, fatigue, or unexplained illness
👍 Most common reality
In most people, a single red line on one nail = minor injury, not a serious disease.
If you want, you can describe it more (which finger, how many lines, pain or not), and I’ll help you narrow it down more accurately.
