Definition
Allergic reaction to plasma proteins in the donor unit (often against a specific donor); difficult to avoid and usually unpredictable.
Range from mild to severe (including anaphylaxis), with symptoms including flushing, urticaria or rash, wheeze, bronchospasm, stridor, angiodema and circulatory problems (not typically associated with fever type symptoms).
Frequency
Mild: Common (≥1/100 to <1/10).
Moderate & Severe: Rare (≥1/10,000 to <1/1,000).
Reducing the risk
A small number of people may have recurrent allergic reaction to transfusion.
Measures to mitigate this include use of: platelets in additive solution, prophylactic antihistamine, 'washed' red cells, solvent-detergent treated plasma.
Treatment as per local protocol (using antihistamine, adrenaline or steroids as indicated).
Further information/ resources
SHOT bites No 5. Febrile allergic and hypotensive transfusion reactions (FAHR)
SHOT Febrile Allergic and Hypotensive Reactions Webinar (2020)
Handbook of Transfusion Medicine: Non-infectious hazards of transfusion