In the world of fiction, illnesses always progress as quickly as a heart attack. A person feeling ill will drop down within minutes of the first signs of an illness. Similarly, only hours or minutes remain for an antidote to take effect. To be fair, many diseases have a very fast progression (septicemic plague, for example, was described in Medieval writing as "the man [[IncurableCoughOfDeath coughs]] at dawn, takes to his bed at noon, and is dead by sundown.") but this trope is about diseases that more ''unusually'' fast (i.e. at the speed of plot).


This unrealistically speedy disease progression, apart from the need to squash a 24-hour or week-long disease into the 1 or 2 hours you can keep viewers interested, is motivated by the RuleOfDrama: Nobody cares about an illness that takes weeks to develop.
See also TravellingAtTheSpeedOfPlot. Contrast SoapOperaDisease and VictorianNovelDisease

----
!!Examples

[[AC:{{Anime}} and {{Manga}}]]
* In Creator/YuuWatase's manga ''Manga/{{Imadoki}}'', early in their acquaintance, Kugyou finds Tanpopo planting flowers in the rain, and she suddenly collapses with a fever. She [[WhyDidItHaveToBeSnakes hates hospitals]], so he takes her back to her apartment instead, and has to take care of her--including changing her clothes while she's unconscious.
* This happens a few times in ''Manga/HanaYoriDango'' but the most ridiculous example is when Tsukushi falls into a swimming pool in a warm, tropical setting and instantly gets a bad fever. This prevents her from getting physical with Domyoji when they are finally alone together.
* In the fourth episode of ''Manga/SeitokaiYakuindomo'', Tsuda seemed perfectly healthy until the moment he steps out from under an umbrella. Within seconds he sneezes and is sick for the next episode.
* In ''Manga/FruitsBasket'', Yuki tends to collapse pretty quickly if he's in the cold or overexerts himself. It's explained that he was pretty sickly as a child, and his massive self esteem issues [[spoiler:brought on by being abandoned by his family and tormented by the head of the house]] no doubt contributed.
* Shiina of ''Manga/KoufukuGraffiti'' would have this when she has [[WeaksauceWeakness water splashed on]].

[[AC:{{Film}}]]
* In Creator/CharlieChaplin's ''[[Film/TheKid1921 The Kid]]'', John, Charlie's DoorstopBaby, is feeling feisty enough to beat up a kid twice his size. Not more than ten minutes later, John is severely ill, so sick that he has to be carried back to Charlie's little apartment.

[[AC:{{Literature}}]]
* The ''Literature/ChaletSchool'' books are pretty bad for this, probably because of ValuesDissonance and girls being considered to be delicate, as well as the school's large IllGirl contingent. Any exposure to chills, rain, drafts, mud or cold water is fairly certain to leave the victim in the grip of a life-threatening disease if they're not immediately put into a hot bath and then into bed with two hot water bottles. In one book, Jo spends three days unconscious and is bedridden for over a week after standing for literally a few minutes by an open door on a snowy day.
* ''Literature/GalaxyOfFear'' once has Tash given an injection that, within hours, has her sweating, feeling [[NotHimself unusually irritable]], and growing a rash-covered lump on that arm. ''Then'' it starts oozing, [[spoiler: because it's the BlobMonster [[TheVirus Virus]]]]. The one responsible actually coolly observes that the disease isn't progressing in her as fast as he'd expected.

[[AC:{{Live Action TV}}]]
* Happens every week on ''{{House}}'', although the show handwaves it by saying that the patient only sought Dr. House's help when the diseases is at its final stages (when it can progress that fast), or because the overly invasive diagnostic tests and treatments House prescribed is causing an adverse reaction.

[[AC:{{Radio}}]]
* ''Radio/OurMissBrooks'': In "Measles", Miss Brooks catches the measles within twelve hours of being exposed to them.
----