In summary, HAE is a dominantly inherited form of angioedema which is manifested by nonpainful, nonerythematous, nonpruritic and nonpitting swelling of the extremities, face, gastrointestinal and respiratory tracts unaccompanied by urticaria. These patients have deficient activity of the C1 INH and the laboratory diagnosis can be easily made by finding low C4 and C1 inh levels during an attack. Effective and specific therapy is now available that prevents the clinical syndrome and corrects the serologic hallmarks of the disease.