What is the management for a patient experiencing a suspected allergic reaction, characterized by swelling, hives, pallor, numbness, and tingling, during a Venofer (iron sucrose) infusion?

Management of Suspected Allergic Reaction During Venofer Infusion

Stop the infusion immediately and administer intramuscular epinephrine 0.3-0.5 mg if this represents a moderate-to-severe hypersensitivity reaction with systemic symptoms (swelling, hives, pallor, paresthesias). 1

Immediate Assessment and Stabilization

First Actions (Within 60 Seconds)

• Stop the Venofer infusion immediately but maintain IV access 1
• Call for medical assistance and prepare emergency equipment 1
• Assess ABCs (Airway, Breathing, Circulation) and measure vital signs including blood pressure, pulse rate, respiratory rate, and oxygen saturation 1

Determine Reaction Severity

This patient's presentation suggests a Grade 2-3 hypersensitivity reaction based on:

• Urticaria (hives) = cutaneous involvement 1
• Swelling of hands/feet = possible angioedema 1
• Pallor = potential circulatory compromise 1
• Paresthesias (numbness/tingling) = neurological symptoms that may indicate evolving anaphylaxis 1

Critical distinction: If the patient develops hypotension, bronchospasm, respiratory distress, or loss of consciousness, this becomes anaphylaxis requiring immediate epinephrine. 1

Treatment Algorithm

For Suspected Anaphylaxis (Hypotension, Bronchospasm, or Respiratory Compromise)

Epinephrine is the first-line treatment:

• Administer epinephrine 0.3-0.5 mg (1 mg/mL) intramuscularly into the anterolateral thigh 1
• Repeat every 5-15 minutes if inadequate response 1
• Aggressive fluid resuscitation: Normal saline 1-2 L IV at 5-10 mL/kg in first 5 minutes, then crystalloid boluses of 20 mL/kg 1

Adjunctive medications (after epinephrine and fluids):

• H1/H2 antagonists: Diphenhydramine 50 mg IV plus ranitidine 50 mg IV 1
• Corticosteroids: Methylprednisolone 1-2 mg/kg IV every 6 hours (equivalent dose) 1

For Grade 2 Hypersensitivity Reaction (No Hypotension/Bronchospasm)

If vital signs remain stable without evidence of anaphylaxis:

• Slow or temporarily stop the infusion 1
• Administer H1/H2 antagonists: Diphenhydramine 50 mg IV plus ranitidine 50 mg IV 1
• Consider corticosteroids: Methylprednisolone 1-2 mg/kg IV 1
• Monitor vital signs continuously for progression to anaphylaxis 1

Do NOT restart the Venofer infusion given the severity of symptoms (swelling, hives, paresthesias). 1

Post-Reaction Management

Observation Period

• Monitor in a supervised area for minimum 6 hours or until symptoms completely resolve and patient is stable 1
• Continue vital sign monitoring every 15 minutes initially, then every 30 minutes 1
• Watch for biphasic reactions, though risk is relatively low 1

Diagnostic Testing

• Obtain serum tryptase levels optimally at 15 minutes to 3 hours after symptom onset, then a baseline level 24 hours later for comparison 1
• Note that normal tryptase does not rule out hypersensitivity reaction 1

Future Iron Replacement Strategy

Avoid Venofer (Iron Sucrose)

• Document this reaction clearly as a hypersensitivity reaction to iron sucrose 2
• Avoid all future exposure to Venofer 2

Alternative Approaches

Option 1: Switch to different IV iron formulation

• Iron sucrose can be safely replaced with ferric carboxymaltose in patients with prior iron sucrose hypersensitivity 2, 3
• Case reports demonstrate successful iron sucrose administration after ferric gluconate reactions, suggesting limited cross-reactivity between different IV iron preparations 2

Option 2: Desensitization protocol (if IV iron absolutely required)

• One-bag 8-step ferric carboxymaltose desensitization has been successfully performed in patients with prior anaphylaxis to iron preparations 3
• Requires allergy specialist consultation and controlled setting 3
• Premedication with dexamethasone (8 mg night before and morning of treatment) plus diphenhydramine may be used 2

Option 3: Oral iron replacement

• Consider if patient can tolerate oral route and rapid repletion not required 2

Critical Pitfalls to Avoid

• Never restart the same iron preparation after a systemic hypersensitivity reaction 1
• Do not delay epinephrine if anaphylaxis is suspected—it is the only life-saving medication 1, 4
• Antihistamines and corticosteroids are adjuncts only, not substitutes for epinephrine in anaphylaxis 1, 4
• Avoid routine premedication for future iron infusions as it may mask early warning signs of severe reactions 5
• Do not assume all IV iron products will cause the same reaction—different formulations have distinct allergenic profiles 2, 3