It is a painless, nonpruritic, nonpitting, and wellcircumscribed edema caused by increased vascular
permeability. This may come and go rather quickly (over a period of hours), typically involving the head
and neck (the face, lips, floor of the mouth, tongue, and larynx), but also other regions of the body. In fact, it may involve the gastrointestinal tract, causing intestinal wall edema with colicky abdominal pain, nausea,
vomiting, and diarrhea. In more serious cases, it may even cause life-threatening laryngeal edema, with
stridor, upper airway obstruction, and respiratory failure. Although nonpruritic, angioedema is usually
allergic in origin, triggered by medications, foods (berries, shellfish, fish, nuts, eggs, and milk), pollen,
animal dander, insect bites, environmental exposure (water, sunlight, cold or heat),and emotional stress. It
may even follow infectious illnesses or be associated with autoimmune disorders and leukemia.