A swelling of the skin, eyes, lips, mouth, or tongue. The swelling occurs just below the skin. At times it can be very serious and block off the airway preventing a patient from breathing. The disorder can be part of an allergic reaction and be associated with hives. Some patients have a familial form (hereditary angioedema) that results from low levels of a protein called C1 inhibitors. A small group of patients will have a reaction to a type of blood pressure medications called ACE (Angiotensin Converting Enzyme) inhibitors manifested as angioedema of the lips, eyes, tongue or mouth. Common ACE inhibitors include: captopril (Capoten), lisinopril (Lisodur, Lopril, Novatec, Prinivil, Zestril), enalapril (Vasotec, Renitec), ramipril (Altace, Tritace, Ramace, Ramiwin), quinapril (Accupril), fosinopril (Monopril), and benazepril (Lotensin).