Vitamin C Deficiency: Diagnosis and Treatment
Diagnostic Approach
Diagnose vitamin C deficiency clinically based on characteristic symptoms—do not delay treatment while awaiting laboratory confirmation if clinical features are present. 1
Clinical Features to Identify
- Pathognomonic skin findings: Perifollicular hemorrhages and "corkscrew" hair appearance are diagnostic 2
- Mucocutaneous bleeding: Petechiae, ecchymoses, bleeding gums, and gingival swelling 1, 2
- Musculoskeletal manifestations: Bone pain, joint contractures from periosteal and intraarticular bleeding 2
- General symptoms: Fatigue, poor wound healing, generalized weakness 2, 3
Laboratory Testing Considerations
- Plasma vitamin C measurement is the preferred diagnostic test when laboratory confirmation is needed 4
- Critical caveat: Plasma levels are unreliable during inflammation—vitamin C levels decline when CRP >10 mg/L, and normal values are not detected if CRP >40 mg/L 4
- Testing is only recommended for suspected scurvy or chronic low intake, NOT during acute inflammation or critical illness 1
- Strict pre-analytical procedures are required: immediate centrifugation at 4°C, ultra-low temperature storage (-70 to -80°C), and light protection 4
High-Risk Populations to Screen
- Alcoholism, tobacco smoking, severe psychiatric illness 2, 5
- Low socioeconomic status, older age, male sex 2
- Chronic dialysis, critical illness, major surgery 4
- Post-bariatric surgery patients 4
Treatment Protocol
Standard Repletion Therapy
Initiate oral vitamin C 100 mg three times daily (300-500 mg/day total) for at least one month for symptomatic deficiency. 1
- Alternative regimen: 250 mg twice daily for 3 weeks for clinical scurvy 1
- Single daily dosing option: 500 mg once daily for 1 month 1
- Do not delay treatment waiting for laboratory confirmation if clinical symptoms suggest scurvy 1, 2
Route of Administration
- Oral administration is standard for uncomplicated deficiency 4
- Use IM, IV, or subcutaneous routes when malabsorption is suspected 4
- IV vitamin C should be diluted with normal saline or glucose to minimize adverse reactions 4
Special Clinical Scenarios Requiring Higher Doses
- Critically ill patients during acute inflammation: 2-3 g/day IV 4, 1
- Continuous renal replacement therapy: 2-3 g/day IV 4, 1
- Cardiac surgery (perioperative): 1-2 g/day IV for 5-7 days 4, 1
- Chronic oxidative stress conditions (diabetes, chronic inflammation): 200-500 mg/day 4, 1
- Post-bariatric surgery maintenance: 200-500 mg/day long-term 4, 1
Maintenance After Repletion
- Healthy adults: 75-90 mg/day (achievable with one medium-sized orange) 1, 2
- High-risk populations: Continue 200-500 mg/day indefinitely 1
Treatment Duration and Monitoring
- Continue treatment for minimum 1 month for symptomatic deficiency 1
- Continue until clinical symptoms resolve and adequate dietary intake is established 1
- Expect rapid clinical improvement: Resolution of skin lesions and joint contractures typically occurs within 2 weeks 2
- Do not routinely recheck vitamin C levels during treatment—clinical response is the best indicator 2
Critical Safety Considerations
Contraindications to high-dose vitamin C (>1 g/day):
- Hemochromatosis (risk of iron overload) 6
- G6PD deficiency (risk of hemolysis) 6
- Active oxalate kidney stones (vitamin C metabolizes to oxalate) 6
- Severe renal dysfunction (oxalate accumulation risk) 6
Common Pitfalls to Avoid
- Do not dismiss scurvy in well-nourished appearing patients—malabsorption can cause deficiency despite adequate intake 3
- Do not confuse vitamin C deficiency with hematologic disorders, vasculitis, or anticoagulant side effects—perifollicular hemorrhages and corkscrew hair distinguish scurvy 2
- Do not measure vitamin C levels in acutely ill or inflamed patients—results will be falsely low and misleading 4
- Do not use vitamin C as routine pharmacotherapy for sepsis—current evidence does not support this practice 6
- Consider gastrointestinal workup if oral supplementation fails to correct deficiency—malabsorption may be present 3