immunology allergic disorders
Angioedema
Chronic angioedema
The cause of chronic (>6 weeks) angioedema is usually unknown. IgE-mediated mechanisms are rare, but chronic ingestion of an unsuspected drug or chemical (eg, penicillin in milk, a nonprescription drug, preservatives, other food additives) is sometimes the cause. A few cases are due to hereditary or acquiredC1 inhibitordeficiency. Idiopathic angioedemais angioedema that occurs without urticaria, is chronic and recurrent, and has no identifiable cause. 