Allergic reactions

2011–12 Data Summary (n=147)
Age		Sex		Day of Transfusion
0–4 years	6	Male	67	Week day	126
5–14 years	9	Female	53	Weekend	21
15–24 years	12	Uncategorised	27
25–34 years	9	Facility Location		Time of Transfusion
35–44 years	12	Major City	103	Between 7am and 7pm	63
45–54 years	19	Inner Regional	16	Between 7pm and 7am	10
55–64 years	29	Outer Regional	2	Unknown	74
65–74 years	24	Remote	-
75+ years	26	Very Remote	-
Not specified	1	Uncategorised	26
Clinical Outcome Severity		Imputability		Blood Component
Death	-	Excluded/Unlikely	1	Whole blood	-
Life threatening	2	Possible	20	Red cells	56
Severe morbidity	13	Likely/Probable	89	Platelets	54
Minor morbidity	128	Confirmed/Certain	35	Fresh Frozen Plasma	36
No morbidity	4	Not assessable	2	Cryoprecipitate	1
Outcome not available	-		-	Cryodepleted plasma	-

2012–13 Data Summary (n=111)
Age		Sex		Day of Transfusion
0–4 years	9	Male	43	Week day	91
5–14 years	5	Female	38	Weekend	20
15–24 years	11	Uncategorised	30
25–34 years	14	Facility Location		Time of Transfusion
35–44 years	7	Major City	75	Between 7am and 7pm	19
45–54 years	10	Inner Regional	2	Between 7pm and 7am	5
55–64 years	16	Outer Regional	5	Unknown	87
65–74 years	14	Remote	-
75+ years	21	Very Remote	-
Not specified	4	Uncategorised	29
Clinical Outcome Severity		Imputability		Blood Component
Death	-	Excluded/Unlikely	3	Whole blood	-
Life threatening	-	Possible	13	Red cells	42
Severe morbidity	10	Likely/Probable	77	Platelets	35
Minor morbidity	96	Confirmed/Certain	7	Fresh Frozen Plasma	34
No morbidity	5	Not assessable	11	Cryoprecipitate	-
Outcome not available	-			Cryodepleted plasma	-

Notes

QLD data is unavailable for 2012–13.
Sex and facility location data is unavailable for NSW.
Time of transfusion data is unavailable for NSW and SA.
Data is unavailable for WA.
Uncategorised refers to those reports where no data was provided.

Allergic reactions (see Appendix II: Definitions in haemovigilance) are the second most common transfusion-related adverse events reported in Australia. In combined financial years 2011–12 and 2012‑13, 258 allergic reactions were reported to the National Haemovigilance Program, accounting for 24.7% of the reports (1,044) for this period. The number of allergic reactions dropped from 147 in 2011–12 to 111 in 2012–13 due to the unavailability of QLD data.

In the five financial years to 2012–13:

The number of severe allergic reactions reported rose by 69.0% from 87 in 2008–09 to 147 in 2011–12, mainly due to increased reporting of this event from NSW, QLD and SA. The number of allergic reactions dropped in 2012–13 due to the unavailability of QLD data.
There was one reported death in 2008–09 and no reported deaths from 2009–10 to 2012–13. The number of cases reported with life threatening severity dropped from 16 in 2008–09 to 2 in 2011–12 and 0 in 2012‑13.
The number of cases reported with minor morbidity increased from 16 in 2008–09 to 128 due to the inclusion of NSW data in 2011‑12 and dropped to 96 in 2012-13 (likely due to the unavailability of QLD data).

The lack of SA and NSW data for transfusion time and NSW data for facility location contributed to large numbers of unknown/uncategorised cases for two categories in 2011–12 and 2012–13.

In the period 2011–12 to 2012–13, 80.6% of cases (208) were assigned an imputability score of likely/probable or confirmed/certain, including 20 cases with severe morbidity and two with life threatening severity. The confirmed case of life threatening severity was related to the transfusion of red cells.

Table 8: Severe allergic reaction clinical outcome severity by imputability, 2011–12 and 2012–13
Clinical Outcome Severity	Imputability					Total
	Excluded / Unlikely	Possible	Likely / Probable	Confirmed / Certain	N/A / Not assessable
Death
2011–12	‑	‑	‑	‑	‑	‑
2012–13	‑	‑	‑	‑	‑	‑
Life threatening
2011–12	-	-	1	1	-	2
2012–13	-	-	-	-	-	-
Severe morbidity
2011–12	-	1	9	3	-	13
2012–13	-	1	7	1	1	10
Minor morbidity
2011–12	1	19	77	29	2	128
2012–13	3	12	67	4	10	96
No morbidity
2011–12	-	-	2	2	-	4
2012–13	-	-	3	2	-	5
Outcome not available
2011–12	-	-	-	-	-	-
2012–13	-	-	-	-	-	-
Total	4	33	166	42	13	258

Notes

Outcome severity and imputability data unavailable for QLD for 2012–13.
Outcome severity and imputability data unavailable for WA.

Symptoms of allergic reactions may include urticaria (hives), oedema, pruritis, and angioedema. Urticarial reactions are presumably due to soluble antigens in the donor unit to which the recipient has been previously sensitised, and are typically dose-dependent.

Allergic reactions are a common complication of blood transfusion. Leucoreduction has no effect on decreasing incidence rates,^[12] suggesting that cytokines released from white blood cells during storage are likely not responsible. Unless the patient has a history of transfusion-related severe allergic reactions, these incidents are difficult to predict.

Clinical recommendation

The Blood Service provides guidance on the recognition, investigation and management of severe allergic reactions.^[13]

When to suspect these adverse reactions?
This reaction can range from one lesion to widespread urticarial lesions. This is commonly the only symptom but may be associated with mild upper respiratory symptoms, nausea, vomiting, abdominal cramps or diarrhoea. This occurs in 1–3% of transfusions.
Usual causes?
Hypersensitivity to allergens or plasma proteins in the transfused unit.
Investigation
Generally no investigations are required.

If there is more than simple urticaria, haemolysis should be excluded: DAT, blood count and repeat ABO grouping may be indicated.
What to do?
Stop transfusion immediately and follow other steps for managing suspected transfusion reactions.

Antihistamines may be given and once the reaction subsides, continue transfusion at a slow rate and complete within 4 hours of commencement.

Consult a haematologist before administering additional blood packs.

Consider premedication and/or washed red cells if the patient has recurrent allergic reactions to transfusion.