Abstract
We report a 10-year-old patient with haemophilia A developing anaphylaxis to recombinant factor VIII (octocog alfa). Allergic reactions, and especially anaphylactic events, are rare in patients with haemophilia A. The nature of these reactions is not fully understood. Here, we demonstrate a type I hypersensitivity reaction using sodium dodecyl sulfate-polyacrylamide gel electrophoresis immunoblotting assay. This test revealed itself as an essential diagnostic tool, as it allowed us to choose an alternative treatment (moroctocog alfa). Its safety was later confirmed by an uneventful challenge test.