What are the potential causes of red lines in my fingernails?

Reviewed by Yoshinori Abe, MD

Internal Medicine

Red lines in the fingernails, often called splinter hemorrhages, can appear for several reasons. Common causes include minor nail trauma, skin conditions like psoriasis or eczema, nutritional deficiencies, and underlying health changes. In some cases, they have also been linked to post-COVID-19 effects or more serious conditions such as endocarditis or vasculitis.

Because red lines under the nails can signal anything from a harmless bump to a condition that needs medical attention, it's important not to guess. The fastest way to understand what may be causing your symptoms—and what to do next—is to take a free, instant, online symptom check. In just a few minutes, you'll get personalized insights based on your unique symptoms, helping you decide whether home care, a doctor's visit, or urgent evaluation is the right next step.

Reviewed for medical accuracy: 07/15/2026

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Explanation

Red lines in fingernails can appear for different reasons, and understanding them can help you know when to seek advice from a healthcare provider.

Skin Conditions: According to the first reference, certain skin conditions can cause red bands on nails. These might be linked to changes in the way the skin or nails grow.
Health Changes: The second reference mentions that sometimes nails can show changes even in healthy people, like 'half and half nails,' which might not be a sign of a problem.
COVID-19 Effects: The third reference highlights that COVID-19 can cause nail changes, including red lines, as part of its wide-ranging effects on the body.

If you notice red lines in your nails, it might be helpful to check your symptoms with Ubie's free AI-powered tool to better understand what might be causing them. You can then discuss the results with a healthcare provider if you're concerned, as they can help determine if the changes are related to a health condition or something else.

(References)

Chang C, Beutler BD, & Cohen PR. (2017). Report of a Patient with Multiple Horizontal Red Bands .... Dermatology and therapy, 28260214.
Oanță A, Iliescu V, & Țărean S. (2017). Half and Half Nails in a Healthy Person. Acta dermatovenerologica Croatica : ADC, 30064606.
Preda-Naumescu A, Penney K, Pearlman RL, Brodell RT, Daniel CR, & Nahar VK. (2021). Nail Manifestations in COVID-19: Insight into a Systemic .... Skin appendage disorders, 34580633.

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