The definition of angioedema is an edema of subcutaneous and submucosal tissues due to increased vascular permeability and fluid extravasation. It can affect different areas, including extremities, genitals, upper airways and intestinal mucosa. The symptoms are disabling and this condition can be fatal if it involves the larynx. We can distinguish different forms of angioedema (hereditary and acquired) with different pathogenetic mechanisms, therefore responding to different treatments. Bradykinin-mediated angioedema (such as hereditary angioedema due to C1-inhibitor deficiency) does not respond to the standard therapy used for histamine-mediated angioedema. These forms should be immediately recognized and specific treatment should be used. In addition, when a patient manifests hypotension not responding to fluid replacement and associated with diffuse edema, hypoalbuminemia and hemoconcentration, we should consider the diagnosis of idiopathic systemic capillary leak syndrome, a very rare but fatal condition.