Q. A 51-year-old man comes to the emergency department for swollen lips that he observed after waking up from bed a few hours ago. He denies itching or pain. He doesn’t have a similar history in the past. His medical history shows that he is a known hypertensive for the past 6 years and is on an Angiotensin-converting enzyme (ACE) inhibitor twice daily. Family history is insignificant. His temperature is 98.6°F (37°C), pulse is 86/min, blood pressure is 130/80 mmHg, and respirations are 14/min. Physical examination shows grossly swollen lips and the rest of the examination is normal. Which of the following statements is true about the condition that this patient is suffering from?