Types of Angioedema
Acute Allergic Angioedema
Acute allergic angioedema is the most common type of angioedema that occurs because of an allergic reaction. In this type of angioedema, the body mistakenly identifies certain harmless external substances, such as food or medications, as harmful. It then releases certain chemicals to attack these external substances. These chemical reactions in the body lead to angioedema and cause the skin to swell.
Acquired angioedema is an immune system disorder characterized by swelling that can occur anywhere on the body; the lips and the skin around the eyes are the most frequently affected, but the tongue and the mucous membranes of the throat, mouth, and intestines also may swell. This type is caused by antibodies destroying C1-inhibitor.
Hereditary angioedema is inherited and occurs due to genetic abnormalities that cause a deficiency in the levels of C1 protein. It is a chronic disease characterized by sudden but temporary swelling in the deeper layers of the skin that usually appears on its own, without hives or a rash. Hereditary angioedema is divided into three subtypes.
Idiopathic angioedema is a broad class of angioedema given to cases of an unknown cause. It consists of a type of swelling that can occur anywhere on the body, but most frequently appears around the lips and eyes. This type is often chronic, relapsing, and mostly accompanied by hives or urticaria.
Non-allergic angioedema is caused by a reaction to medications such as angiotensin-converting enzyme (ACE) inhibitors. The swelling can occur anywhere on the body, though the lips and the skin around the eyes are most frequently affected. The onset of this type may vary from days to months after first taking the medication.