Splinter hemorrhages

Splinter hemorrhages look like thin, red to reddish-brown lines of blood under the nails. They run in the direction of nail growth.

They are named splinter hemorrhages because they look like a splinter under the fingernail. The hemorrhages may be caused by tiny clots that damage the small capillaries under the nails.

Splinter hemorrhages can occur with infection of the heart valves (endocarditis). They may be caused by vessel damage from swelling of the blood vessels (vasculitis) or tiny clots that damage the small capillaries (microemboli).

Causes may include:

• Bacterial endocarditis
• Injury to the nail

There is no specific care for splinter hemorrhages. Follow your health care provider's instructions for treating endocarditis.

Contact your provider if you notice splinter hemorrhages and you haven't had any recent injury to the nail.

Splinter hemorrhages most often appear late in endocarditis. In most cases, other symptoms will cause you to visit your provider before splinter hemorrhages appear.

Your provider will examine you to look for the cause of splinter hemorrhages. You may be asked questions such as:

• When did you first notice this?
• Have you had an injury to the nails recently?
• Do you have endocarditis, or does your provider suspect that you have endocarditis?
• What other symptoms do you have, such as shortness of breath, fever, general ill feeling, or muscle aches?

The physical exam may include special attention to the heart and blood circulation systems.

Laboratory studies may include:

• Blood cultures
• Complete blood count (CBC)
• Erythrocyte sedimentation rate (ESR)

In addition, your provider may order:

• Chest x-ray
• Electrocardiogram (ECG)
• Echocardiogram

After seeing your provider, you may want to add a diagnosis of splinter hemorrhages to your personal medical record.

Fingernail hemorrhage

Lipner SR, Scher RK. Nail signs of systemic disease. In: Callen JP, Jorizzo JL, Zone JJ, Piette WW, Rosenbach MA, Vleugels RA, eds. Dermatological Signs of Systemic Disease. 5th ed. Philadelphia, PA: Elsevier; 2017:chap 44.

Tosti A. Diseases of hair and nails. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 409.

Wright WF. Fever of unknown origin. In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 9th ed. Philadelphia, PA: Elsevier; 2020:chap 56.

Updated by: Linda J. Vorvick, MD, Clinical Professor, Department of Family Medicine, UW Medicine, School of Medicine, University of Washington, Seattle, WA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.