What might red lines across my fingernails indicate?

Reviewed by Yoshinori Abe, MD

Internal Medicine

Red lines across your fingernails, known as splinter hemorrhages, can be caused by a range of health issues. Common causes include nail trauma, skin conditions like psoriasis, fungal infections, and vitamin deficiencies. In some cases, they may signal underlying conditions such as endocarditis (a heart infection), diabetes, or autoimmune diseases like lupus.

Because red lines on your nails can point to anything from a minor injury to a serious systemic condition, understanding the cause is key to knowing your next steps. Taking a free, instant, online symptom check can help you evaluate your symptoms in minutes, identify possible causes based on your unique health profile, and guide you on whether to monitor at home or seek medical care—empowering you to make informed decisions about your health.

Reviewed for medical accuracy: 07/15/2026

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Explanation

Red lines on your fingernails can be a sign of several possible conditions. According to the provided references, these lines could be related to skin diseases or systemic conditions that affect your body. For example, horizontal red bands on nails might be linked to skin problems or infections.

Possible Causes:

Skin Conditions: Some skin diseases can cause changes in your nails, including red lines.
Infections: Certain infections, like those associated with COVID-19, can also lead to nail changes.
Systemic Health Issues: Changes in your overall health, such as nutritional deficiencies or other illnesses, might show up as changes in your nails.

If you notice red lines or other changes in your nails, you can use Ubie's free AI symptom checker to learn more about what might be causing them and whether you should seek medical attention.

(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.
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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