Sensitivity to poison ivy is genetic.
The character played by guest star Kay Lenz is Karen Palmieri, whose son, Mike Palmieri has a heart complication following a football game. The mother-son duo's last name, Palmieri, is in honor of the director of photography, Anthony R. Palmieri, who worked all of Season 7.
James T. Callahan stars as Mr. Bristol, a man who brought his wife in after she stopped breathing. Callahan has starred in Something New (1997), as a patient of Anna del Amico. He was starred as an Anterograde Amnesia patient named Oliver who had cancer.
Originally titled "Indian Summer".
Mark Valley playing Richard Lockhart, and Wentworth Miller playing Mike Palmieri, have both appeared in the CW's The Flash (2014).