Swelling of the Face, Lips or Throat — This Is a Medical Emergency

Any swelling that involves the lips, tongue or throat is an emergency — treat it as one without waiting. If breathing feels tight, swallowing is difficult, or you feel faint, go immediately. Mild flushing or skin redness without any of those features is less dangerous, but if there is any doubt, treating it as an emergency is the safer choice. Do not assess this alone: tell someone with you what is happening and ask them to stay with you.

Not necessarily. Your oncologist will review what happened and how severe the reaction was. Some reactions are managed with pre-medication — antihistamines or steroids given before the next infusion — and the drug continues. Others require switching to a different agent. That decision depends on the severity and whether a safe alternative exists for your cancer type. This conversation should happen with your oncologist once you have been assessed, not during the emergency itself.

You will be assessed immediately and your airway, breathing and circulation checked. If anaphylaxis is confirmed, the team will give adrenaline. You may also receive antihistamines, steroids and oxygen, and be monitored until stable. Tell the team you are on chemotherapy and the name of the drug if you know it. Bringing your treatment summary or drug list helps the team make decisions quickly.

No. Antihistamines do not stop anaphylaxis. They may ease itching from a mild skin reaction, but they cannot prevent the throat from swelling or reverse a dangerous drop in blood pressure. Taking one and waiting at home is dangerous when throat tightness or breathing difficulty is present. Go to emergency first. After you have been safely assessed, your oncology team can discuss antihistamines as a preventive measure before future cycles.