Dictionary Definition:
noun, from the verb exacerbate:
to make more violent, bitter, or severe
~ Merriam-Webster
Elizabeth's take on this term...
When there is a flare-up of new or existing symptoms, typically severe enough to recognize that something intense is going on in the body that is causing increased pain, discomfort, and/or dysfunction. They indicate the presence of increased inflammation in the body.
Exacerbations are also known as attacks, flares, relapses, or flare-ups of symptoms.