Anaphylaxis may be defined as a severe, life-threatening, generalised or systemic hypersensitivity reaction.

Common identified causes of anaphylaxis:

• food (e.g. nuts) - the most common cause in children
• drugs
• venom (e.g. wasp sting)

Features

The Resus Council UK define anaphylaxis as:

• the sudden onset and rapid progression of symptoms
• Airway and/or Breathing and/or Circulation problems

Airway problems may include:

• swelling of the throat and tongue →hoarse voice and stridor

Breathing problems may include:

• respiratory wheeze
• dyspnoea

Circulation problems may include:

• hypotension
• tachycardia

This means that if there are no ABC problems then the patient is technically not having anaphylaxis.

Around 80-90% of patients also have skin and mucosal changes: