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"Why does blood get trapped beneath fingernails?"

ZocdocAnswersWhy does blood get trapped beneath fingernails?


Why does blood get trapped beneath your fingernails? My partner works carpentry and is always banging up his hands, and I can't stand the way blood looks when it's pooled up under his nails. Is there no way to get rid of it?


There is a large vascular network subsiding under the fingernails called a capillary bed. This can be seen by flashing a flashlight under your fingertip and viewing the reddish hue coming from your fingernail. This is also the reason that you can see a great deal of bleeding if you cut them too short. Severe trauma to the fingernail can cause these capillary beds to rupture and leave blood underneath the fingernail. The medical term for this is subungual hematoma. This is a relatively benign condition, and usually this blood will be resorbed by the body with time. If it causes continued or worsening pain symptoms, doctors can evacuate the blood clot by piercing the fingernail. This usually expressed the blood clot and the nail will heal with time. There is also a risk that an infection can form under the fingernail which can be very painful. Again, doctors can evaluate and pierce or trephenate the nail to express the underlying abscess and will likely also treat with a long course of antibiotics. If your partner is complaining of constant pain associated with these subungual hematomas, you may consider recommending to him to be evaluated by his primary care physician and decide what further treatment options are available to him.

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