Anaphylaxis is a multisystem hypersensitivity reaction that is characterised by acute onset with characteristic skin features, with the potential for cardio-respiratory complications.
Signs and Symptoms
- Respiratory/chest – cough, wheeze, stridor, tongue swelling
- Cardiovascular – palpitations, tachycardia, bradycardia, hypotension
- Neurological – headaches, dizziness, altered consciousness
- Gastrointestinal – nausea, vomiting, diarrhoea, abdominal pain
- Dermatological – urticarial rash, erythema/flushing, angio-oedema
Anaphylaxis is a diagnosis made on a clinical basis.
Below are a number of differentials based on different presentations of anaphylaxis:
- Tissue swelling – urticaria
- Upper airway oedema – acute oesophageal reflux (sudden onset of painful throat “swelling”)
- Flushing syndromes
- Peptide-secreting tumours (eg, carcinoid syndrome, VIPomas)
- Medullary carcinoma of thyroid
- Red man syndrome (associated with vancomycin infusion)
- Neurological syndromes – Epileptic seizure and stroke
- Other causes of collapse – Vasovagal episodes and shock (other causes)
- Acute respiratory distress – Asthma, panic disorders and laryngospasm
- Remove allergen that precipitated the reaction
- Place the child in the supine position and keep them still
- Inject intramuscular adrenaline (10 micrograms/kg or 0.01 ml/kg of 1:1000), into the lateral thigh. Repeat after 5 minutes if there is no improvement.
See the DFTB module on Anaphylaxis: https://dontforgetthebubbles.com/anaphylaxis-module/