Police Scotland are appealing for witnesses following the incident in a vennel off Musselburgh High Street on Wednesday at 1pm.
A 17-year-old male was meeting an individual to pay for a guitar and at this time a man stole his wallet and subsequently assaulted him.
It is understood that there were witnesses to this incident and anyone who can help Police Scotland with their investigation is urged to come forward.
The suspect is described as white, around 19 or 20-years-old, 5ft 10ins tall with a slim build and very short dark hair. He was wearing a grey top with black spots on the front, blue jeans, and green Wellington boots.
Police Sergeant Jon Fleetwood said: "The victim suffered some painful injuries to his face and was obviously very upset at the theft of his money.
"We would ask that anyone who remembers seeing any suspicious activity around Musselburgh High Street on Wednesday afternoon contacts police immediately.
"In addition, anyone who recognises the description of the suspect and can help us trace him is also asked to come forward."
Those with information can contact Police Scotland on 101 or alternatively, the charity Crimestoppers on 0800 555 111.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules hereComments are closed on this article