Allison is Jordan Sullivan's friend.
After Ben Sullivan died, Jordan's friends Allison and Maddie came to town for the funeral. They stuck around for several days, and their presence got on a very tempremental Perry Cox's nerves. Perry vented to J.D., who went and asked them to leave town. Dr. Cox later realized that they stayed in town to Jordan's spirits up because Perry was too busy moping in self pity. ("My Tormented Mentor")