Are red lines under nails indicative of any specific health condition?

Reviewed by Yoshinori Abe, MD

Internal Medicine

Red lines under the nails, medically known as erythronychia, are thin reddish or purplish streaks that appear beneath the nail plate. They can result from minor causes like nail trauma, but may also signal underlying conditions such as splinter hemorrhages, endocarditis, psoriasis, or autoimmune disorders. Sudden appearance, multiple nails affected, or changes over time warrant evaluation by a healthcare provider.

Because red lines under the nails can range from harmless to a warning sign of something serious, the smartest next step is to clarify what's driving your symptoms before they progress. Take a free, instant, online symptom check to get personalized insights and guidance on what to do next.

Reviewed for medical accuracy: 07/15/2026

Quick answers

Frequently Asked Questions

4 answers

The most common questions people search after this page

Concerned about your symptoms?

Start a symptom check

Explanation

Red lines under nails, referred to as erythronychia, can appear as either horizontal or vertical lines. They may occur due to trauma to the nail or be related to underlying health conditions.

Causes:

Trauma: Injury to the nail can cause red lines.
Health Conditions: In some cases, these lines may indicate problems like infections or other systemic diseases.

Types:

Horizontal Lines: These can occur from repeated trauma or pressure on the nails.
Vertical Lines: Known as longitudinal erythronychia, they may appear due to more serious conditions and should be evaluated by a healthcare provider.

If you notice red lines under your nails, especially if they appear suddenly or change, it is important to determine the underlying cause. You can start by taking a free AI symptom checker test to help identify potential health issues before consulting with a healthcare provider for appropriate action.

(References)

Chang C, Beutler BD, & Cohen PR. (2017). Report of a Patient with Multiple Horizontal Red Bands .... Dermatology and therapy, 28260214.
Cohen PR. (2011). Longitudinal erythronychia: individual or multiple linear red .... American journal of clinical dermatology, 21668031.
Lipner SR, & Scher RK. (2016). Evaluation of nail lines: Color and shape hold clues. Cleveland Clinic journal of medicine, 27168515.

Tell your friends about us.

We would love to help them too.

For First Time Users

What is Ubie’s Doctor’s Note?

We provide a database of explanations from real doctors on a range of medical topics. Get started by exploring our library of questions and topics you want to learn more about.

Was this page helpful?

Purpose and positioning of servicesUbie Doctor's Note is a service for informational purposes. The provision of information by physicians, medical professionals, etc. is not a medical treatment. If medical treatment is required, please consult your doctor or medical institution. We strive to provide reliable and accurate information, but we do not guarantee the completeness of the content. If you find any errors in the information, please contact us.