A woman with recurrent spontaneous throat swelling

A woman in her 30s presented with sudden onset difficulty in breathing, a swelling sensation of her throat and tongue, audible stridor, and a rash across the upper chest. On arrival at the emergency department she had already self-injected adrenaline using an auto-injector and paramedics had administered intramuscular adrenaline and nebulised salbutamol. Despite initial improvement, the symptoms recurred in the emergency department. Observations at this stage were: heart rate 136 beats/min, systolic blood pressure 178 mm Hg, and oxygen saturation 100% while receiving oxygen 15 L/min through a mask and reservoir bag. No wheeze was present. She received further intramuscular adrenaline, intravenous corticosteroids, and antihistamines and was moved to the respiratory high dependency unit for observation. The same symptom complex recurred several times over the next four days, each episode leading to treatment for anaphylaxis and resolution of symptoms within minutes. On one occasion, nasendoscopy on the ward immediately after symptom resolution was unremarkable, with no evidence of angio-oedema.

The patient’s history included well controlled asthma and identical episodes intermittently over the previous two years, with no clear trigger and apparent resolution of symptoms after use of an adrenaline auto-injector. At that time a working diagnosis of recurrent spontaneous anaphylaxis was in place.

Previous investigations showed normal complement (C4) (excluding angioedema caused by C1 esterase inhibitor deficiency) and normal serial tryptase levels. The patient described associated stress and gastro-oesophageal reflux symptoms.

Flexible nasendoscopy in the ear, nose, and throat clinic showed …