Some articles on anaphylactoid:

Radiocontrast Agent - Adverse Effects - Anaphylactoid Reactions
... Anaphylactoid reactions occur rarely, but can occur in response to injected as well as oral and rectal contrast and even retrograde pyelography ... reactions, however, are at increased risk of anaphylactoid reactions ... Anaphylactoid reactions range from urticaria and itching, to bronchospasm and facial and laryngeal edema ...