immunology allergic disorders
Angioedema
Diagnosis of Angioedema
Clinical evaluation For diagnosis of urticaria, see Evaluation . Patients with localized swelling but no urticaria are asked specifically about use of ACE inhibitors. The cause of angioedema is often obvious, and diagnostic tests are seldom required because most reactions are self-limited and do not recur. When angioedema is acute, no test is particularly useful. When it is chronic, thorough drug and dietary evaluation is warranted. levels to Diagnosis and C4 levels to check for hereditary or acquired angioedema. Low levels of C4, even between episodes, may help confirm a diagnosis of hereditary angioedema (types 1 and 2) or acquired Diagnosis may mimic allergic forms of angioedema; both can cause edema and erythema after exposure to sunlight. The two can be distinguished by measuring blood and fecal porphyrins. If angioedema is not accompanied by urticaria and recurs without clear cause or is present in family members, consider hereditary or acquired angioedema. 