Splinter hemorrhages under fingernails (clinical significance)
Splinter hemorrhages are small, linear bleeding under the nail plate from injury or from disease-related damage to nail-bed microvessels. [1][2] Most cases are caused by local trauma and resolve without systemic consequence. [1][3][2] Certain patterns or associated systemic symptoms increase the clinical concern for systemic inflammatory or embolic disease, including infective endocarditis. [3][4][7]
Pathophysiology of splinter hemorrhages
Splinter hemorrhages result from extravasation of blood from longitudinal nail-bed vessels. [1][6] They can occur from direct vessel injury (most commonly distal nail trauma) or from vessel-wall inflammation/occlusion that produces microemboli or vasculitis-related hemorrhage. [1][3][5]
Common benign significance (local trauma)
Distal subungual splinter hemorrhages are frequently caused by minor trauma. [3][5] Local causes include nail-bed microtrauma from impact or nail manipulation. [1][3] A self-limited course supports a traumatic etiology. [2][1]
Serious systemic significance (infective endocarditis)
Splinter hemorrhages can be a peripheral vascular finding in subacute infective endocarditis. [7][3] Their diagnostic value for infective endocarditis is limited because sensitivity is low. [4] In a diagnostic accuracy study using the Duke criteria as the comparator, splinter hemorrhages had sensitivity of 26% (95% CI 22% to 31%) and specificity of 83% (95% CI 79% to 86%). [4] High diagnostic concern is increased by systemic features such as fever and a cardiac murmur in addition to splinter hemorrhages. [8][7]
Other systemic conditions associated with splinter hemorrhages
Splinter hemorrhages are associated with systemic vasculitis and other inflammatory disorders through nail-bed microvascular injury. [1][5] They are also described in systemic disease contexts including psoriasis and connective tissue diseases. [6][5][1] Nail changes in systemic disease literature supports that nail-bed hemorrhages are among several nail findings that may reflect systemic microangiopathy. [6][9]
Clinical evaluation priorities
Evaluation is driven by (1) number of nails involved, (2) distribution (distal versus more proximal), and (3) presence of systemic symptoms such as fever, weight loss, or other embolic/vascular phenomena. [3][7] Trauma history supports local bleeding. [1][3] Fever plus a potential cardiac source increases concern for infective endocarditis and warrants prompt medical assessment. [7][8] If systemic disease is suspected, laboratory assessment and cardiac evaluation may be required based on clinical context. [7][8]
Practical interpretation of “clinical significance”
Single or few splinter hemorrhages without systemic symptoms most often have limited clinical significance and are consistent with trauma. [3][2][1] Splinter hemorrhages can carry diagnostic significance for infective endocarditis because specificity is relatively higher even though sensitivity is low. [4] In systemic disease settings, splinter hemorrhages serve as a clue to microvascular injury and should trigger targeted assessment for inflammatory or embolic causes when suggested by the clinical picture. [1][6][5]
Targets for clinician action (based on risk)
Urgent evaluation is indicated when splinter hemorrhages occur with systemic symptoms concerning for infective endocarditis. [7][8] Non-urgent evaluation is indicated when splinter hemorrhages are recurrent, involve multiple nails, or occur without clear trauma. [3][6] Local traumatic splinter hemorrhages typically resolve and generally do not require systemic workup in isolation. [2][1]