Examples include respiratory arrest (such as airway obstruction in cases of choking or asphyxiation), toxicity or poisoning, anaphylaxis, or trauma.
en.wikipedia.org Parenteral use of iodine-based contrast agents (see above) can cause reactions ranging from a mild rash to fatal anaphylaxis.
en.wikipedia.org Some common symptoms include itchiness, swelling, running nose, watery eyes, coughing, wheezing, trouble breathing, hives, rashes, mucus production, or a more severe reaction anaphylaxis.
en.wikipedia.org