What are the causes of bruising on the tongue?

Causes of Bruising on the Tongue

Tongue bruising results primarily from trauma (biting, dental procedures, sharp teeth), anticoagulant medications (especially warfarin), bleeding disorders, or rarely from spontaneous hematoma formation in patients on blood thinners.

Traumatic Causes

Self-inflicted biting trauma is the most common cause of tongue bruising and ulceration, particularly in children and patients with neurological conditions. 1

• Chronic biting from sharp dental edges, residual roots, or malocclusion produces localized bruising and ulceration at the site of repeated trauma. 2, 3
• Thermal burns, chemical injuries, and mechanical trauma from dental procedures can all cause tongue bruising and subsequent ulceration. 2
• Post-traumatic trigeminal neuropathic pain can develop within 3-6 months following dental procedures or facial trauma, though this typically presents with burning and tingling rather than visible bruising. 2

Medication-Related Causes

Warfarin therapy is a well-documented cause of spontaneous tongue hematoma, particularly when drug-drug interactions elevate INR levels. 4

• Anticoagulants (warfarin, DOACs), antiplatelet agents (aspirin, clopidogrel), NSAIDs, and corticosteroids all increase bruising tendency throughout the body, including the tongue. 5, 6
• Topical antifungals (miconazole) and macrolide antibiotics (clarithromycin) interact with warfarin to precipitate dangerous INR elevation and spontaneous tongue hematoma with necrosis. 4
• A complete medication review including over-the-counter drugs and supplements is essential when evaluating unexplained tongue bruising. 6

Bleeding Disorders

Von Willebrand disease is the most common inherited bleeding disorder (prevalence 1 in 1000) and presents with mucocutaneous bleeding including oral cavity bruising, but is not detected by standard PT/aPTT screening. 5, 6

• Hemophilia (Factor VIII or IX deficiency) causes significant bruising even with mild deficiencies. 5
• Factor XIII deficiency is not detected by PT/aPTT but can cause significant bruising. 5, 6
• Platelet function disorders present with normal platelet counts but abnormal function, requiring specialized testing like platelet aggregation studies. 5
• Immune thrombocytopenia (ITP) causes low platelet counts and increased bruising risk. 5

Systemic Medical Conditions

Liver disease and cirrhosis decrease clotting factor production, leading to spontaneous bruising including oral cavity involvement. 5

• Disseminated intravascular coagulation (DIC) can cause any type of bruising or bleeding, including in the oral cavity. 5
• Malignancies and infiltrative disorders cause thrombocytopenia or coagulation abnormalities. 5
• Vitamin K deficiency prolongs PT and possibly aPTT, increasing bruising tendency. 5
• Ehlers-Danlos syndrome, scurvy, and other connective tissue disorders predispose to easy bruising. 6

Diagnostic Approach

Initial laboratory testing should include complete blood count with platelet count, PT, aPTT, and fibrinogen level. 5, 6

• Normal PT/aPTT does not rule out bleeding disorders, as these tests miss von Willebrand disease, Factor XIII deficiency, and platelet function disorders. 5, 6
• If PT and aPTT are normal but clinical suspicion remains high, specific VWD testing (VWF antigen, ristocetin cofactor activity, Factor VIII activity) is required. 5
• Coagulation tests are very sensitive to specimen handling and should be performed in experienced laboratories to avoid false-positive results. 5
• If blood products have been transfused, delay screening for bleeding disorders until elimination of transfused clotting elements. 5

Critical Clinical Pitfalls

Assuming normal PT/aPTT excludes bleeding disorders is incorrect—von Willebrand disease and Factor XIII deficiency require specific testing beyond routine coagulation panels. 5, 6

• In patients on warfarin with tongue hematoma, close monitoring of INR is essential when using medications with known drug-drug interactions, and consider switching to a direct oral anticoagulant if no contraindication exists. 4
• Traumatic causes should be identified and eliminated (smoothing sharp teeth, using oral appliances for self-biting) to prevent recurrence. 1, 3
• Referral to hematology is indicated when specialized testing (platelet function studies, VWD multimer analysis, Factor XIII assay) is needed or when initial workup is abnormal. 5