How should itching that begins during or shortly after plasma transfusion be managed?

Management of Itching During or After Plasma Transfusion

Stop the transfusion immediately, maintain IV access, assess vital signs, and administer diphenhydramine 25-50 mg IV for symptomatic relief—but first rule out life-threatening anaphylaxis or bacterial contamination before assuming this is a simple allergic reaction. 1, 2, 3

Immediate Assessment Algorithm

When itching occurs during or shortly after plasma transfusion, you must systematically evaluate for severity:

Step 1: Stop the transfusion and maintain IV access 1, 2

• Never continue the transfusion despite "just itching" as isolated symptoms can mask early signs of serious reactions 2
• Keep the IV line open with normal saline 2

Step 2: Assess for anaphylaxis criteria 4

• Check for hypotension (systolic BP <90 mmHg or drop ≥30 mmHg from baseline) 5
• Evaluate for respiratory symptoms: dyspnea, chest tightness, bronchospasm, wheezing, or oxygen saturation <92% 4, 5
• Look for skin manifestations beyond isolated itching: urticaria, angioedema, or generalized flushing 4, 5
• Document vital signs including heart rate, blood pressure, respiratory rate, and oxygen saturation 2

Step 3: If anaphylaxis is present (hypotension OR respiratory distress OR multi-system involvement):

• Administer epinephrine 0.01 mg/kg (maximum 0.5 mL of 1mg/mL dilution) intramuscularly into the lateral thigh immediately 4
• Position patient in Trendelenburg if hypotensive, or sitting upright if respiratory distress 4
• Administer oxygen as needed 4
• Call for emergency medical assistance 4
• Epinephrine can be repeated every 5-15 minutes if no response 4

Management of Isolated Itching (Mild Allergic Reaction)

If the patient has only itching without hypotension, respiratory symptoms, or multi-system involvement, this represents a mild allergic transfusion reaction:

Immediate treatment:

• Administer diphenhydramine 25-50 mg IV or orally for symptomatic relief 1, 3
• Consider second-generation antihistamines (cetirizine 10 mg IV/oral or loratadine 10 mg oral) as alternatives to avoid sedation 1
• Monitor vital signs continuously for 30-60 minutes to detect progression 1

Critical pitfall: Plasma and platelet products carry higher risk of allergic reactions (1:591 to 1:2,184 units) compared to red blood cells, so heightened vigilance is warranted 6, 7, 8

Decision to Resume or Abort Transfusion

If symptoms resolve completely with antihistamine treatment:

• The transfusion may be cautiously resumed at a slower rate after symptoms fully resolve 4, 1
• Continue close monitoring throughout the remainder of the transfusion 1

If symptoms persist or worsen despite treatment:

• Abort the transfusion permanently 2
• Send the blood component bag with administration set back to transfusion laboratory 2
• Document the reaction for future transfusion planning 1

Prevention for Future Transfusions

For patients with documented previous allergic reactions to plasma:

• Premedicate with antihistamine (diphenhydramine 25-50 mg or cetirizine 10 mg) 30-60 minutes before transfusion 1, 5
• Avoid first-generation antihistamines when possible due to sedation and potential to exacerbate hypotension 1

Evidence against routine premedication:

• Do NOT routinely premedicate all patients without prior reactions, as this lacks efficacy and may mask early warning signs of serious reactions like hemolytic reactions or bacterial contamination 1
• Routine premedication can delay critical intervention for life-threatening complications 1

For patients with recurrent severe allergic reactions:

• Consider washed plasma products to remove donor plasma proteins, though this is resource-intensive 9
• Slower infusion rates are protective and should be used 1

Red Flags Requiring Escalation

Watch for these symptoms that indicate progression beyond simple allergic reaction:

• Temperature ≥40°C (104°F) suggests bacterial contamination 5
• Chest tightness or pain within minutes suggests acute hemolytic reaction or anaphylaxis 2
• Fever with chest tightness occurring within minutes is a medical emergency 2
• Development of hypotension, respiratory distress, or multi-system symptoms requires immediate epinephrine 4, 5

Common Pitfalls to Avoid

• Never assume itching is always benign: Bacterial contamination from platelets can present with fever within 6 hours and is a leading cause of transfusion-related mortality 2
• Never use first-generation antihistamines routinely: They cause sedation and can exacerbate hypotension 1
• Never continue transfusion without stopping first: Even mild symptoms require immediate cessation to assess severity 1, 2
• Never give corticosteroids for mild reactions: Reserve these for moderate-to-severe reactions only 1