I have a patient who came in for an Allergy shot and waited in the lobby for a short time and left. Within 30 minutes of leaving he came back to the office with severe reaction, swelling, etc. He was then seen and had a full work-up. Obviously we would need to bill the e&m and 95117 for allergy. But do I need to add a specific modifier besides 25 on e&m? How would you bill this? Thanks!