How to treat bruising caused by vitamin B12 (cobalamin) deficiency?

Treatment of Bruising Caused by Vitamin B12 Deficiency

For bruising caused by vitamin B12 deficiency, the most effective treatment is vitamin B12 supplementation at 1000-2000 μg daily via sublingual or intramuscular routes, with intramuscular administration preferred for severe cases to achieve more rapid improvement. 1

Diagnosis Confirmation

Before initiating treatment, confirm B12 deficiency with appropriate testing:

• Initial testing should use either:

  • Total B12 (serum cobalamin) or
  • Active B12 (serum holotranscobalamin)

• Interpret results according to these thresholds 1:

  • Confirmed deficiency: Total B12 <180 ng/L or active B12 <25 pmol/L
  • Indeterminate: Total B12 180-350 ng/L or active B12 25-70 pmol/L
  • Unlikely deficiency: Total B12 >350 ng/L or active B12 >70 pmol/L

• For indeterminate results, measure serum methylmalonic acid (MMA) to confirm deficiency 1

Treatment Protocol

Initial Treatment

• Oral/Sublingual Option:

  • 1000-2000 μg daily 1
  • As effective as intramuscular administration for correcting symptoms in most cases 2

• Intramuscular Option:

  • 1000 μg monthly 1
  • Preferred for severe deficiency or severe symptoms due to more rapid improvement 2
  • Consider more frequent administration initially (loading dose) 3

Special Considerations

• Route selection based on cause:

  • For dietary deficiency: Oral supplementation is usually sufficient 3
  • For malabsorption: Parenteral (intramuscular) administration is preferred 3

• Treatment frequency:

  • Standard maintenance: 1000 μg intramuscularly every two months after initial loading 3
  • Up to 50% of individuals may require more frequent administration (every 2-4 weeks) to remain symptom-free 3

Monitoring Response

• Expect improvement in bruising and other symptoms within weeks of starting treatment 1
• Hematologic response should show improvement within 4 weeks 1
• Regular monitoring schedule 1:
  • Assessments at 3,6, and 12 months in the first year
  • At least annual monitoring thereafter
  • Include renal and liver function tests alongside B12 levels

Addressing Underlying Causes

Identify and address the underlying cause of B12 deficiency:

• Dietary insufficiency:

  • Common in vegans, vegetarians, elderly, and malnourished individuals 4
  • Recommend B12-rich foods: eggs, milk, red meat, poultry, fish, and shellfish 4

• Malabsorption issues:

  • Atrophic gastritis
  • Gastrointestinal surgeries
  • Inflammatory bowel disease
  • Medications (proton pump inhibitors, metformin) 4, 2

Long-term Management

• For dietary deficiency: Daily oral supplementation (1000 μg) 5
• Post-bariatric surgery: 1000 μg oral B12 daily indefinitely 1
• Malabsorption disorders: May require higher doses or intramuscular administration 1
• Elderly patients (>75 years): Higher risk due to age-related decline in absorption capacity 1

Important Caveats

• Do not base treatment frequency on biomarker measurements alone; clinical response should guide therapy 3
• Untreated B12 deficiency can lead to irreversible neurological complications 1
• Oral supplementation may not be sufficient for patients with malabsorption issues 3
• Treatment should continue until the underlying cause is addressed or indefinitely if the cause cannot be corrected