While on rounds, Dr. Kelso asks, "can anyone tell me the dermatologic condition associated with rhinophyma?" and calls on Doug to answer. Rhinophyma is a condition where the nose gets large and "bulbous," and is caused by untreated rosacea, which makes the face red, or in other words, a large red nose. Coincidentally, Doug is wearing a fake red clown nose for Halloween.
When Dr. Turk is advising Dr. Wen to be 'Dr. Zen', Dr. Wen replies that he has done 10,000 surgeries in 15 years which means that Dr. Wen has performed 666.66 surgeries per year, fitting with the Halloween theme.
First appearance of Dan Dorian.
The car J.D.'s brother, Dan Dorian, is driving is a late model Mercedes-Benz SL R129. Most likely a 2001 "Silver Arrow" Edition.
The answer Dr. Kelso is looking for when he asks about the dermatological condition associated with rhinophyma is untreated rosacea.