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Transfusion medicine

Tranfusion reaction

Allergic and anaphylactic transfusion reaction

Reviewer: Huy Phu Pham, M.D. (see Reviewers page)
Revised: 31 October 2011, last major update September 2011
Copyright: (c) 2007-2011, PathologyOutlines.com, Inc.


● Allergic transfusion is most common transfusion reaction occurs in all types of product but less common with pRBCs
● Most reactions are mild; occur in 0.030.61% of pRBC transfusions, 0.36% of platelet transfusions, 13% of plasma transfusion
● Anaphylactic reactions occur in 1:20,000 to 1:47,000 components transfused
● May also occur in autologous transfusions (Arch Pathol Lab Med 2003;127:316)
● Anaphylactic reactions associated with IgA deficiency or haptoglobin deficiency, especially in Asian patients; incidence 1:1000 recipients


● Much of the pathophysiology is still unknown

Type I hypersensitivity reaction
● Allegen (usually a protein in the plasma of the transfused product) binds to cell-associated IgE --> activation of mast cells --> release of mediators (cytokines, histamines, leukotrienes, Curr Opin Hematol 2003;10:419)

● Patients with congenital IgA deficiency may develop anti-IgA antibodies; exposure to IgA can lead to anaphylactic reaction
● 1:500 blood donors are IgA deficient, and 1:1200 blood donors have anti-IgA antibodies, but most are not at risk of an anaphylactic transfusion reaction (Immunohematol 2004;20:226)

Antibodies to other normal plasma proteins
● Patients with antibodies to other plasma proteins, such as haptoglobin, C3/C4, alpha-1-antitrypsin) can also have anaphylactic transfusion reactions

Components within blood products
● Transfusion of the allergen which the patient has an antibody against or the antibody which the patient has an allergen for can lead to anaphylactic transfusion reactions

Clinical features

● The shorter the onset of symptoms from transfusion, the more severe the reaction (in general)
● Anaphylactic reactions tend to happen within seconds to 45 minutes after the start of the transfusion
● Other allergic reactions can occur up to 23 hours after completion of the transfusion

Mild allergic reaction:
● No fever
● Pruritis, uticaria, erythema, cutaneous flushing, angioedema, nausea, vomiting, diarrhea, abdominal pain
● 10% have only pulmonary symptoms

Anaphylactic reaction:
● Symptoms of allergic reactions plus hypotension, tachycardia, chest pain, loss of consciousness, arrhythmia, shock, cardiac arrest, wheezing
● No fever
● Patient can have upper and lower airway obstruction --> hoarseness, stridor, dypsnea


● Mostly a clinical diagnosis
● In patients with severe allergic or anaphylactic transfusion reaction, test for IgA deficiency and anti-IgA antibody; test for haptoglobin deficiency and antibody in Asian patients


Mild allergic reaction:
● Temporarily stop the transfusion
● Maintain IV access
● Give diphenhydramine 2050 mg PO or IV (depending on the severity)
● If the symptoms resolve, restart the transfusion slowly
● If the symptoms do NOT resolve, stop the transfusion
● Always report the reaction to the transfusion medicine service even when the transfusion continues

Severe allergic or anaphylactic reaction
● Stop the transfusion
● Maintain IV access with normal saline
● Administer oxygen
● Intubation may be needed
● Epinephrine is most effective medication for treatment of anaphylaxis
● Steroid and H1-receptor antagonists have been used
● Observe the patient closely
● Report the reaction to the transfusion medicine service


In patients without prior history of allergic reaction:
● Routine use of premedication with diphenhydramine or steroids does not decrease the incidence of allergic reactions (Transfus Med Rev 2007;21:1, Br J Haematol 2005;130:781)

In patients with prior history of allergic reaction:
● Predmedication with diphenhydramine or steroids may be helpful, depending on the severity of the previous reaction
● Allergic reactions tend to be more severe with repeated plasma/platelet transfusions
● In patients with severe reaction, use of washed or plasma-reduced pRBCs or platelets might be considered
-Transfuse slowly
-Observe patient closely
-Appropriate medications and equipment should be available

In patients with IgA deficiency:
● It is NOT necessary to restrict patients with IgA deficiency or anti-IgA antibodies to washed or IgA-deficient products, WITHOUT a trial of unmodified products
● Transfuse slowly
● Observe closely for severe reaction
● Appropriate medications and equipment should be available to treat if severe reaction occurs

In patients with IgA deficiency AND history of anaphylactic reaction:
● May need to receive IgA-deficient products (from IgA deficient donors) or washed products
● Resuspending platelets in a nonprotein storage solution instead of fresh frozen plasma may be helpful (Transfusion 2002;42:556)
● Autologous donation can be considered

Case reports

● 4 year old girl receiving blood from mother (Acta Anaesthesiol Scand 2002;46:1276)

End of Transfusion Medicine > Tranfusion reaction > Allergic and anaphylactic transfusion reaction

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