Sudden onset symptoms are symptoms that develop quickly. They can also be called quick onset symptoms or acute symptoms. Sudden onset symptoms can change over time, worsen rapidly, and be severe. They are different from symptoms that develop slowly over a period of time, which are called chronic symptoms.

What does from the onset mean?

When something is at its onset, it's at the beginning, just getting started, and it's often something that's not so pleasant. The onset of hurricane season is probably not the best time to visit the beach.

What does onset mean medically?

Medical Definition of onset

: the initial existence or symptoms of a disease the onset of scarlet fever.