This is frequently associated with urticaria. The swelling can be caused by many factors including Allergic reactions from foods or medications. The swelling can be life threatening. Finding a cause can be challenging. Angioedema can also be inherited or acquired, as in inherited C-1 esterase deficiency or acquired C-1 esterase deficiency. Through laboratory tests and allergy testing a cause may be found. Treatment of this condition will depend on the cause. Special medications are sometimes needed.