Heparin-induced anaphylactic and anaphylactoid reactions: two distinct but overlapping syndromes

BACKGROUND: Heparin-induced anaphylactic and anaphylactoid reactions are of increasing clinical and scientific interest, particularly given the recent identification of a syndrome of heparin-induced anaphylaxis due to oversulfated chondroitin sulfate (OSCS), a contaminant in certain heparin preparations. However, heparin-induced anaphylactoid reactions also have been reported to be a consequence of immune-mediated heparin-induced …