Angioedema in the emergency department: a practical guide to differential diagnosis and management

Table 1 Results of diagnostic tests to help distinguish among angioedema types [1, 21, 47, 48]

	C1-INH concentration	C1-INH function	C4 concentration	Tryptase concentration^*
HAE type I	Low	Low	Low	Normal
HAE type II	Normal or High	Low	Low	Normal
HAE with normal C1-INH	Normal	Normal	Normal	Normal
Acquired AE	Low	Low	Low	Normal
ACEI-induced AE	Normal	Normal	Normal	Normal
Histamine-mediated anaphylaxis	Normal	Normal	Normal	Normal or Elevated

^*In blood drawn within 4–6 h of onset of attack
ACEI angiotensin converting enzyme inhibitor, AE angioedema, C1-INH C1 inhibitor, HAE hereditary angioedema

ISSN: 1865-1380