Angioedema, lymphoproliferative disorder and angiotensin-converting enzyme inhibitors: masking of diagnosis by corticosteroids

Angioedema is a relatively common clinical disorder. Although most cases are idiopathic, the use of angiotensin‐converting enzyme inhibitors is a well recognized cause of angioedema and a further rare but important diagnostic consideration is acquired C1 inhibitor deficiency. We discuss the diagnosis of C1 inhibitor deficiency in angioedema, with reference to a case in which the diagnosis was initially masked by the use of corticosteroids, which normalized the C1 inhibitor level.