What causes persistent bruises that don't fade after a few months?

Persistent Bruises: Causes and Evaluation

Persistent bruises that don't fade after a few months are most likely caused by an underlying bleeding disorder, connective tissue disorder, or medication effect, and require prompt hematologic evaluation to rule out serious conditions that could impact morbidity and mortality. 1

Medical Conditions That Can Cause Persistent Bruising

Bleeding Disorders

• Von Willebrand disease (VWD) - most common inherited bleeding disorder 2
• Hemophilia (factor VIII or IX deficiency) - may present with persistent bruising 2
• Factor XIII deficiency - not detected by routine screening tests 2
• Acquired hemophilia - can develop later in life with inhibitors to clotting factors 3
• Platelet function disorders - can cause mucocutaneous bleeding and bruising 2

Other Medical Conditions

• Ehlers-Danlos syndrome - connective tissue disorder 2
• Scurvy (vitamin C deficiency) - rare but can cause easy bruising 2
• Cancer and infiltrative disorders - can affect platelet production 2
• Pernicious anemia - can be associated with acquired bleeding disorders 3
• Vitamin K-dependent clotting factor deficiency - can present with multiple bruises 4

Diagnostic Approach

Initial Laboratory Testing

• Complete blood count with peripheral blood smear
• Prothrombin time (PT) and International Normalized Ratio (INR)
• Activated partial thromboplastin time (aPTT)
• Fibrinogen level 1

Interpretation of Initial Results

• Normal PT and aPTT with persistent bruising may indicate:

  • Platelet function disorder
  • Von Willebrand disease
  • Factor XIII deficiency
  • Mild hemophilia (which may not cause abnormal aPTT) 2

• Prolonged aPTT with normal PT suggests:

  • Intrinsic pathway disorder (hemophilia A or B)
  • Presence of inhibitors to clotting factors 3, 1

• Prolonged PT with normal aPTT suggests:

  • Extrinsic pathway disorder 1

Additional Testing Based on Initial Results

• If VWD is suspected: von Willebrand factor antigen, ristocetin cofactor activity
• If platelet dysfunction is suspected: platelet aggregation studies or PFA-100 2
• If factor deficiency is suspected: specific factor assays
• If acquired inhibitors are suspected: mixing studies and inhibitor assays 3

When to Suspect Non-Medical Causes

While bleeding disorders must be considered, it's important to note that certain bruising patterns may raise concern for non-accidental trauma, particularly in children:

• Bruises in unusual locations (ears, neck, torso, buttocks, genitals) 5
• Patterned bruises suggesting implements or squeezing 5
• Multiple bruises in different stages of healing 5
• Bruising in non-mobile infants 6

Management Approach

1. Document thoroughly: Record precise anatomical location, size, shape, and appearance of bruises 5

2. Obtain detailed history:

   • Timing of bruise appearance
   • Duration of persistence (normal bruises typically resolve within 2-4 weeks)
   • Family history of bleeding disorders
   • Medication use (anticoagulants, NSAIDs, certain supplements)
   • Previous excessive bleeding with procedures 1

3. Consult hematology: When initial evaluation suggests a bleeding disorder or when suspicion remains high despite normal initial laboratory results 1

4. Consider multidisciplinary evaluation: In children with high-risk bruising, both hematologic disorders and non-accidental trauma should be considered, as these can sometimes overlap 7

Key Points to Remember

• Persistent bruises beyond 2-3 months are abnormal and warrant investigation
• Normal screening tests (PT, aPTT) do not rule out all bleeding disorders
• Mild factor deficiencies can still cause significant bruising despite minimal laboratory abnormalities 2
• In children, leg bruises are more common in hematologic disorders while TEN (torso, ears, neck) bruises are more common in abuse cases 7
• Acquired bleeding disorders can develop at any age and may be associated with other medical conditions 3

Prompt evaluation of persistent bruising is essential as it may be the first sign of a serious underlying condition that could affect long-term morbidity and mortality if left untreated.