For patients with the rare immunological syndrome acquired angioedema associated with C1 inhibitor deficiency, replacement therapy with plasma-derived C1 INH concentrate is standard treatment. For those who develop resistance to replacement therapy, another drug has been shown to be successful in managing acute episodes.
Chris, a 55-year-old man, presented to his GP with a 12-month history of recurrent and increasingly frequent and severe episodes of facial swelling (Figure). The swelling would usually develop rapidly during the night and could last up to three to four days. It was not associated with a rash and was unresponsive to antihistamines. The swelling attacks were not painful and the patient did not feel generally unwell. On the most recent of these episodes, he had developed groin swelling at the same time as facial swelling.
The patient had been previously well. Prior to the onset of these facial swellings, he had experienced no lifestyle or dietary change. He was taking no medications and he had no past personal history or family history of any allergic or autoimmune disorder.
Chris was referred for immunological assessment.
What could be the cause of this patient’s swelling episodes?