Splinter hemorrhages are small areas of bleeding (hemorrhage) under the fingernails or toenails.
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).
After seeing your health care provider, you may want to add a diagnosis of splinter hemorrhages to your personal medical record.
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Mackowiak PA, Durack DT. Fever of unknown origin. In: Mandell GL, Bennett JE, Dolin R, eds. Principles and Practice of Infectious Diseases. 7th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2009:chap 51.
Linda J. Vorvick, MD, Medical Director, MEDEX Northwest Division of Physician Assistant Studies, University of Washington, School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.