immunology allergic disorders
Hereditary and Acquired Angioedema
Diagnosis
Measurement of complement levels If angioedema is not accompanied by urticaria and recurs without any clear cause or is triggered by local trauma, clinicians should suspect hereditary angioedema or acquiredC1 inhibitordeficiency. If family members have it, clinicians should suspect hereditary angioedema. Levels of C4,C1 inhibitor, and C1q (a component of C1) are measured. Hereditary angioedema (types 1 and 2) or acquiredC1 inhibitordeficiency is confirmed by Low levels of C4, even between episodes DecreasedC1 inhibitorlevel or function Other findings include Type 1 hereditary angioedema: LowC1 inhibitorprotein levels, decreasedC1 inhibitorfunction, and normal C1q levels Type 2 hereditary angioedema: Normal or increasedC1 inhibitorprotein levels, decreasedC1 inhibitorfunction, and normal C1q levels AcquiredC1 inhibitordeficiency: Low C1q levels Type 3 hereditary angioedema: NormalC1 inhibitorlevel and function and normal C and C1q levels and C4 levels ( Diagnosis reference ). 1.Zuraw BL, Bernstein JA, Lang DM, et al: A focused parameter update: Hereditary angioedema, acquiredC1 inhibitordeficiency, and angiotensin-converting enzyme inhibitor–associated angioedema.J Allergy Clin Immunol131 (6):1491-1493, 2013. doi: 10.1016/j.jaci.2013.03.034 