What you’re describing sounds like a splinter hemorrhage.
What It Is
A splinter hemorrhage appears as small, thin, red to brown lines under the fingernail, usually running in the direction of nail growth. They look like tiny “splinters” or streaks.
Common Causes
- Trauma or injury – bumping or hitting the nail is the most frequent cause.
- Infections – certain infections like endocarditis (infection of the heart valves) can cause them.
- Underlying medical conditions – including psoriasis, vasculitis, or blood clotting disorders.
- Medications – rarely, some drugs affecting blood vessels or clotting can contribute.
When to Seek Medical Attention
- If multiple nails are affected without trauma
- If accompanied by fever, fatigue, or other unusual symptoms
- If you notice other nail changes like pitting, thickening, or discoloration
Prevention & Care
- Protect nails from trauma
- Keep nails clean and trimmed
- Monitor for new or worsening streaks
- See a doctor if unexplained streaks persist, especially if you have heart or autoimmune risk factors
✅ Tip:
Single red streaks after minor injury are usually harmless and grow out with the nail. Persistent or multiple streaks should be evaluated to rule out more serious conditions.
If you want, I can explain how to differentiate harmless trauma lines from those caused by serious medical conditions.