Severe Allergic Reaction

Severe Allergic Reaction (Anaphylaxis)

A severe allergic reaction (anaphylaxis) can be life-threatening. In people susceptible to such reactions, anaphylaxis can occur within minutes or up to several hours after exposure to a specific trigger, and if anaphylactic shock develops, can be fatal.

There are various triggers that may cause allergic reactions in different people, but most commonly they include certain foods – such as peanuts, medications, or insect stings.


The following symptoms may be seen:

  • Skin may break out in hives (red, itchy bumps on the skin) or swellings (usually around eyes and mouth)
  • Difficulty breathing
  • Dizziness and confusion
  • Abdominal cramping, nausea, vomiting or diarrhoea
  • Signs of shock – such as pale, cold, clammy skin, fast, shallow breathing and a rapid, weak pulse

What to do

If you observe someone having a severe allergic reaction:

  • Call 999 (or 112) for an ambulance.
  • A person prone to severe allergic reactions may be carrying special medications, such as a ready-to-use injection kit (e.g., an ‘EpiPen’). Help the person to administer the medication as directed.
  • Help the person to relieve any breathing difficulty, normally by sitting up and leaning forward slightly. Loosen tight clothing to aid breathing.
  • If the person is in shock, then lie them on their back, with their feet higher than the head and cover with a blanket to keep warm
  • If the person has vomited, turn them onto their side to prevent choking.
  • If the person stops breathing or there are no signs of circulation, administer CPR.