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Published on: 8/20/2026

What could be the cause of red lines appearing in my nails?

Yoshinori Abe

Reviewed by Yoshinori Abe, MD

Internal Medicine

Red lines in the nails, often called splinter hemorrhages, are thin streaks of blood that appear underneath the nail. Common causes include:

  • Nail trauma or injury (the most frequent cause)
  • Skin conditions such as psoriasis or eczema
  • Fungal nail infections
  • Underlying health issues, including endocarditis, vasculitis, or nutrient deficiencies

The color, shape, and location of the red lines can offer important clues. Reddish-brown streaks that don't move as the nail grows may suggest an internal cause, while lines linked to a recent bump or injury typically resolve on their own.

Because red lines in the nails can range from harmless to a sign of something more serious, understanding your specific symptoms matters. A free, instant, and private online symptom check can help you identify possible causes based on your unique situation and guide you on what to do next—whether that's monitoring at home or seeing a doctor. Take a moment now to get clarity and confidence about your health.

Reviewed for medical accuracy: 07/15/2026

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Explanation

Red lines in nails, also known as nail lines, can appear due to several reasons. According to the available references, these lines can be associated with trauma to the nail or underlying skin conditions.

Possible Causes:

  1. Trauma: Physical injury to the nail can cause red lines to appear. This could be from hitting your nail or other forms of pressure.
  2. Skin Conditions: Conditions like lichen planus can cause changes in nail appearance, including red lines. This is a skin condition that can affect nails and appears in a specific pattern known as Blaschko lines.

What to Look For:

  • Color and Shape: Observing the color and shape of the lines can provide important clues. For example, if the lines are horizontal, it might indicate a different issue than if they are vertical.

If you notice red lines in your nails, it might be helpful to think about any recent injuries or changes in your health. To better understand what might be causing your symptoms, you can use Ubie's free AI symptom checker to get personalized insights in just a few minutes.

(References)

  • Chang C, Beutler BD, & Cohen PR. (2017). Report of a Patient with Multiple Horizontal Red Bands .... Dermatology and therapy, 28260214.

  • Lipner SR, & Scher RK. (2016). Evaluation of nail lines: Color and shape hold clues. Cleveland Clinic journal of medicine, 27168515.

  • Dong S, Zhu WJ, Xu M, Zhao XQ, & Mou Y. (2022). Unilateral lichen planus with Blaschko line distribution. World journal of clinical cases, 36157808.

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