Gilligan's Island (1964)

S2E28 Allergy Time

The Skipper starts to sneeze and itch whenever he's near Gilligan, and soon, the rest of the Castaways experience similar symptoms. Concerned, the Professor creates a vaccine, but it fails to alleviate their discomfort. Eventually, they discover that the culprit behind the allergies is the papaya oil in Gilligan's hair tonic, which is affecting everyone.