Abstract

C1 inhibitor deficiency is a rare syndrome clinically characterized by recurrent episodes of swelling of subcutaneous tissue or angioedema. It can involve the skin, upper respiratory airways and abdomen. There are two main types: hereditary and acquired. Angioedema can involve practically any part of the cutaneous surface, it can cause lethal laryngeal edema and can present as gastrointestinal obstruction. The attacks can be triggered, in general, by trauma, drugs or infections. Diagnosis is confirmed by decreased serum levels of C4 and absence or marked decrease of the level or function of C1 inhibitor. Commonly employed drugs for prophylaxis and treatment of these patients include anabolic steroids, antifibrinolytic agents, and infusion of C1 inhibitor concentrate. Fresh frozen plasma is an option to be considered for short term prophylaxis or treatment of the acute attack. It is convenient to know this syndrome as it is a potentially life-threatening disease. Diagnosis of this rare syndrome is based on clinical features and characteristic alterations of laboratory tests. The acute attack should be treated as quickly as possible. Prophylactic therapy is indicated in certain circumstances (dental procedures, oral surgery).