Why does anaphylaxis cause facial swelling?

The swelling is often called angioedema. It can appear soon after contact with an allergen and may come with hives, flushing, itching, stomach symptoms, dizziness, or breathing changes. Facial Swelling is a very common presentation of Anaphylaxis. Swelling inside the mouth or throat can narrow the airway even when changes on the skin seem limited.

Facial swelling has causes other than anaphylaxis, including local irritation or infection. The urgent concern is the speed of onset and whether the tongue, throat, voice, breathing, or alertness is affected.

Treat suspected anaphylaxis as an emergency. Use a prescribed adrenaline auto-injector immediately if available, then call emergency services. Lie flat with legs raised if possible; if breathing is difficult, sit with legs extended. Do not stand or walk suddenly. A person who is vomiting or unconscious but breathing should be placed on their side.

If symptoms return or persist after using an auto-injector, emergency clinicians may give further treatment and observation. Avoid food or drink if swallowing is difficult.

Call emergency services immediately for swelling of the tongue or throat, trouble breathing, wheeze, a hoarse voice, faintness, confusion, widespread hives with other symptoms, or collapse after a possible allergic trigger. Emergency assessment is needed even if symptoms improve after adrenaline, because they can recur.

Ask what trigger is suspected, whether allergy testing or specialist referral is appropriate, how to use an adrenaline auto-injector, and what written action plan to carry. Review any medicines, foods, insect stings, latex exposure, or previous reactions that may help identify a pattern.