Angioedema is an area of swelling (edema) of the lower layer of skin and tissue just under the skin or mucous membranes. The swelling may occur in the face, tongue, larynx, abdomen, or arms and legs. Often it is associated with hives, which are swelling within the upper skin. Onset is typically over minutes to hours.The underlying mechanism typically involves histamine or bradykinin. The version related to histamine is due to an allergic reaction to agents such as insect bites, foods, or medications. The version related to bradykinin may occur due to an inherited problem known as C1 esterase inhibitor deficiency, medications known as angiotensin-converting enzyme inhibitors, or a lymphoproliferative disorder.Treatment to protect the airway may include intubation or cricothyroidotomy. Histamine-related angioedema can be treated with antihistamines, corticosteroids, and epinephrine. In those with bradykinin-related disease a C1 esterase inhibitor, ecallantide, or icatibant may be used. Fresh frozen plasma may be used instead. In the United States the disease affects about 100,000 people a year. Signs and symptoms
The skin of the face, normally around the mouth, and the mucosa of the mouth and/or throat, as well as the tongue, swell over the period of minutes to hours. The swelling can also occur elsewhere, typically in the hands. The swelling can be itchy or painful. There may also be slightly decreased sensation in the affected areas due to compression of the nerves. Urticaria (hives) may develop simultaneously.In severe cases, stridor of the airway occurs, with gasping or wheezy inspiratory breath sounds and decreasing oxygen levels.
Additionally, it inhibits various proteins of the coagulation cascade, although effects of its deficiency on the development of hemorrhage and thrombosis appear to be limited. The three types of hereditary angioedema are:

Type I - decreased levels of C1INH (85%);
Type II - normal levels, but decreased function of C1INH (15%);
Type III - no detectable abnormality in C1INH, occurs in an X-linked dominant fashion and therefore mainly affects women; it can be exacerbated by pregnancy and use of hormonal contraception (exact frequency uncertain). It has been linked with mutations in the factor XII gene.Angioedema can be due to antibody formation against C1INH; this is an autoimmune disorder. This acquired angioedema is associated with the development of lymphoma. Consumption of foods that are themselves vasodilators, such as alcoholic beverages or cinnamon, can increase the probability of an angioedema episode in susceptible patients. If the episode occurs at all after the consumption of these foods, its onset may be delayed overnight or by some hours, making the correlation with their consumption somewhat difficult. In contrast, consumption of bromelain in combination with turmeric may be beneficial in reducing symptoms.The use of ibuprofen or aspirin may increase the probability of an episode in some patients. The use of acetaminophen typically has a smaller, but still present, increase in the probability of an episode. Diagnosis
The diagnosis is made on the clinical picture. Routine blood tests (complete blood count, electrolytes, kidney function, liver enzymes) are typically performed.