Another word for rapid onset a short course?

Here are some alternatives for "rapid onset and short course," depending on the specific context:

Emphasizing speed:

* Acute

* Sudden

* Abrupt

* Flash (for very rapid onset)

* Transient

Emphasizing brevity:

* Brief

* Short-lived

* Ephemeral

* Self-limited

Combined emphasis:

* Acute and transient

* Sudden and brief

* Abrupt and short-lived

More specific terms:

* Fulminant (for a very severe and rapid onset)

* Episodic (for repeated short courses)

* Recurrent (for repeated short courses)

Formal terms:

* Rapidly progressing

* Short-duration

Informal terms:

* Quick hit

* Short-lived burst

The best alternative will depend on the specific context of your writing.

Example:

Instead of saying "The patient experienced a rapid onset and short course of symptoms," you could say "The patient experienced acute, transient symptoms."