Immediately after eating, a man develops swelling of face and lips, respiratory distress, intense pruritis, hypotension and feeling of impending doom. Which of the following is the most likely diagnosis?

The classic clinical features developed by the patient immediately after eating suggest a diagnosis of anaphylaxis. Anaphylaxis is a life threatening response occurring within minutes of exposure to specific antigen and is manifested by respiratory distress due to laryngeal edema, intense bronchospasm, often followed by vascular collapse, shock, pruritus, uicaria with or without angioedema, and gastrointestinal manifestations in the form of nausea, vomiting, crampy abdominal pain, and diarrhea. Ref: Harrison Internal Medicine, 18th Edition, Chapter 317