What are the concerns and recommended actions for a patient with a bruise under the skin, possibly taking anticoagulant medications such as aspirin (acetylsalicylic acid) or warfarin?

Management of Bruising in Patients on Anticoagulants

For patients on warfarin or aspirin who develop a bruise under the skin, assess the INR immediately if on warfarin, evaluate the size and location of the bruise, and determine if bleeding is excessive or associated with trauma—most isolated bruises can be managed conservatively with observation, but anticoagulation may need adjustment if INR is supratherapeutic or bleeding is recurrent. 1, 2

Immediate Assessment

For Patients on Warfarin

• Check INR immediately to determine if the patient is within therapeutic range (typically 2.0-3.0 for most indications) 1, 2
• If INR is 3.0-4.5 without significant bleeding, hold the next 1-2 doses of warfarin and resume at a lower dose once INR returns to therapeutic range 1
• If INR is 4.5-9.0 without significant bleeding, hold warfarin and consider oral vitamin K (1-2.5 mg) 1
• For INR >9.0 or clinically significant bleeding, administer vitamin K 3-5 mg orally and monitor closely 1

For Patients on Aspirin

• Evaluate whether aspirin is being used with a clear therapeutic indication (recent MI, cardiac stent, mechanical valve) 1, 3
• Consider discontinuing aspirin if no clear indication exists, as combination therapy with anticoagulants increases bleeding risk 3-6 fold without reducing thrombosis 1, 3
• Aspirin should be stopped 7-10 days before any planned procedure if bleeding risk is concerning 1

Clinical Evaluation of the Bruise

Key Assessment Points

• Document the cutaneous size, location, and appearance of the bruise, noting that visible bruise size does not correlate with subcutaneous depth or severity 4
• Assess for trauma history—bruising at INR ≤3.0 is frequently associated with trauma or underlying lesions 1
• Examine for signs of more serious bleeding: expanding hematoma, compartment syndrome, or involvement of critical areas (retroperitoneal, intracranial) 1
• Check for other bleeding manifestations: gum bleeding, hematuria, melena, or prolonged bleeding from minor cuts 2

Risk Factors for Serious Bleeding

• Age ≥65 years, history of GI bleeding or stroke, renal insufficiency, anemia, or concomitant antiplatelet therapy 1
• Patients with 2-3 risk factors have substantially higher bleeding rates than those with none 1
• Concomitant NSAID use increases bleeding risk through multiple mechanisms: platelet inhibition, GI mucosal damage, and potential pharmacokinetic interactions 1, 5

Management Strategy

Conservative Management (Most Cases)

• Apply local pressure for 5-10 minutes if there is active bleeding 6
• Reassure the patient that isolated bruising does not adversely affect clinical outcomes 6
• Continue anticoagulation if INR is therapeutic and bruising is minor without ongoing bleeding 1
• Avoid NSAIDs completely, as they increase bleeding risk through platelet inhibition and can raise INR by up to 15% when combined with warfarin 1, 5

When to Adjust Anticoagulation

• For warfarin patients with recurrent or excessive bruising in therapeutic INR range, consider lowering target INR to 2.0-2.5 (from 2.0-3.0) or 1.5-2.0 for high-risk patients with atrial fibrillation 1
• For patients requiring both anticoagulation and antiplatelet therapy, initiate GI prophylaxis with proton pump inhibitors 1
• If aspirin is being used without clear indication alongside warfarin, discontinue aspirin as it increases any bleeding by 16% and major bleeding by 73% without reducing thrombosis 3

Monitoring and Follow-up

• Recheck INR within 24-48 hours if dose adjustment was made 1
• Assess injection technique in diabetic patients, as improper insulin administration can cause recurrent bruising 6
• Evaluate for underlying coagulopathy if bruising is excessive, spontaneous, or in unusual locations 1, 6

Special Considerations

Combination Anticoagulant-Antiplatelet Therapy

• The combination of warfarin plus aspirin without clear indication (no recent MI, PCI, or mechanical valve) increases bleeding without reducing thrombosis 3
• At 1 year, combination therapy causes 26% bleeding rate vs 20% with warfarin alone, and 5.7% major bleeding vs 3.3% 3
• If combination therapy is necessary (mechanical valve, recent stent), use lowest effective aspirin dose (≤100 mg/day) and provide GI prophylaxis 1

Warfarin-Induced Skin Necrosis (Rare but Serious)

• Suspect if bruising appears 3-8 days after warfarin initiation with pain disproportionate to appearance, progressing to purpura and necrosis 7
• Immediately discontinue warfarin, give vitamin K and fresh frozen plasma, and switch to heparin 7
• This occurs in 0.01-0.1% of patients, typically in fatty areas (breasts, thighs, buttocks), and is associated with protein C/S deficiency 7

Common Pitfalls to Avoid

• Do not ignore bruising in patients on combination warfarin-aspirin therapy without clear indication—this represents an opportunity to reduce bleeding risk by stopping aspirin 3
• Do not assume visible bruise size reflects severity—ultrasound shows subcutaneous hematoma depth and height do not correlate with cutaneous appearance 4
• Do not prescribe NSAIDs to anticoagulated patients—all NSAIDs impair platelet function and increase bleeding risk, with phenylbutazone and mefenamic acid having additional pharmacokinetic interactions 1, 5
• Do not continue warfarin at the same dose if INR >4.0—this provides no additional benefit and significantly increases bleeding risk 1, 2