Splinter hemorrhages are small areas of bleeding (hemorrhage) under the fingernails or toenails.
Splinter hemorrhages appear as narrow, red-to-reddish-brown lines of blood beneath the nails. They run in the direction of nail growth and are named splinter hemorrhages because they look like a splinter beneath the fingernail. The hemorrhages may be caused by tiny clots that damage the small capillaries under the nails.
Splinter hemorrhages are associated with infection of the heart valves (endocarditis) and may be caused by vessel damage from swelling of the blood vessels (vasculitis) or tiny clots that damage the small capillaries (microemboli).
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