Squabbs Syndrome is a disease that only affects Dragons. The symptoms include no production of fire and frequent sneezing. The treatment includes keeping the dragon warm and feeding plenty of chilli, pepper and a crate of rum four times a day.
Etymology
Probably derived from Swedish dialect "sqvabb" (flabby skin), "sqvabba" (fat woman) ; or from, German "Quabbe" (soft mass) ; or else again, from Norwegian "kvabb" (mud).
Behind the scenes
The existence of the Squabbs Syn. is only shown on a page of notes concerning the book Dragon Breeding for Pleasure and Profit that is available on J.K. Rowling's Official Site. The scan of the page is available here.