Near-fatal anaphylaxis caused by human serum albumin in fibrinogen and erythrocyte concentrates.

A 40-year-old man developed anaphylactic shock during surgical replacement of a prolapsed mitral valve during general anaesthesia and an attenuated reaction (Grade 2), three days later during a blood transfusion. Human serum albumin, a component of the fibrinogen concentrate used postoperatively with the erythrocyte concentrate, was identified as the trigger, confirmed by positive skin prick and intradermal tests. Any anaphylaxis during the peri-operative period should cause the clinician to perform allergy tests for identification of the culprit drug and, sometimes, culprit additive. Testing of human serum albumin, acting as hidden allergen, should be included, especially where there has been a blood transfusion.

Delayed-type hypersensitivity to low molecular weight heparins and heparinoids: cross-reactivity does not depend on molecular weight.

BACKGROUND: Cross-reactivity is a widespread phenomenon in patients who develop cutaneous delayed-type hypersensitivity (DTH) reactions to low molecular weight heparins (LMWHs). As molecular weight is believed to be a key determinant of sensitization to heparins, the recently developed LMWH bemiparin, with the lowest molecular weight of all LMWHs, appeared to be a significant improvement. OBJECTIVES: To evaluate cross-reactivity between bemiparin and several other LMWHs and heparinoids by means of subcutaneous testing. Methods Test doses of bemiparin and several other LMWHs/heparinoids were given to eight patients with a history of local eczematous reactions after subcutaneous injection of enoxaparin. RESULTS: Seven of eight patients showed cross-reactivity following subcutaneous injection of bemiparin. In addition, nearly all tested substances caused local eczematous reactions in at least some patients, with the exception of fondaparinux, which was well tolerated by all patients. Of all substances tested, bemiparin had the highest cross-reactivity with enoxaparin. Substances with a lower molecular weight did not cross-react less frequently than the others. CONCLUSIONS: No significant correlation was found between the molecular weight of the tested substances and the frequency of DTH reactions. In patients with DTH to enoxaparin, the LMWH bemiparin is not a suitable alternative.