Dealing with an Allergic Reaction

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This leaflet is created from first aid advice provided by St John Ambulance, the nation's leading first aid charity. This advice is no substitute for first aid training - find a training course near you.

A severe allergic reaction (anaphylaxis) will affect the whole body; in susceptible individuals it may develop within seconds or minutes of contact with the trigger factor and is potentially fatal.

Possible triggers can include skin or airborne contact with particular materials, the injection of a specific drug, the sting of a certain insect or the ingestion of a food such as peanuts.


  • Impaired breathing: this may range from a tight chest to severe difficulty.
  • There may be a wheeze or gasping for air.
  • Signs of shock.
  • Widespread blotchy skin eruption.
  • Swelling of the tongue and throat.
  • Puffiness around the eyes.
  • Anxiety.


Your aim is to arrange immediate removal of the person to hospital.

  • Dial 999/112/911 for an ambulance.
  • Give any information you have on the cause of the person's condition.
  • Check whether the person is carrying any necessary medication. If they are, help them to use it.

If the person is conscious:

  • Help them to sit up in a position that most relieves any breathing difficulty; this is usually sitting up and leaning forward slightly.

If the person becomes unconscious:

  • Open the airway and check breathing.
  • Be prepared to give rescue breaths and chest compressions.
  • Place them into the recovery position if the person is unconscious but breathing normally.

Note: these hints are no substitute for thorough knowledge of first aid. St John Ambulance holds first aid courses throughout the country.

Adapted from the St John Ambulance leaflet: allergic reactions. Copyright for this leaflet is with St John Ambulance.

Original Author:
St John Ambulance
Current Version:
Peer Reviewer:
St John Ambulance
Document ID:
28671 (v1)
Last Checked:
Next Review:
Now read about Anaphylaxis and its Treatment

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