Brandon, According to the dictionaries I’ve checked, it appears that they could be used as synonyms. However, in my experience the ways in which I have heard these words used would indicate to me that there is a distinction, but perhaps this distinction resides only in my head.
Here, I have selected those portions of the dictionary definitions which support my view and I emphasize that this is only my opinion, based on my experience, and is not gospel:
means to make angry or impatient, annoy greatly, enrage, to cause irritation or annoyance.
means to increase the severity, aggravate, intensify the harshness or grievousness or to increase in virulence or violence, as of pain, disease, or hatred.
The distinction between the two words, as far as I am concerned, is that ‘exasperate’ is generally an emotion that applies to people and ‘exacerbate’ is something that generally applies to things and situations – not people.
: <“The general reader will be exasperated by a certain cavalier cuteness.”—C. H. Driver>, <”She’s a good child but her behavior often exasperates me.”>, <“He was exasperated by the senseless delays.”>
: <“her condition was exacerbated by lack of care.”>, <”foolish words exacerbated the quarrel”>, <“all the frictions that exacerbated the long-drawn-out negotiations”— Howard Taubman>,
<“exacerbating factors in modern life”>, <“the injuries to his pride, exacerbated by her desertion of him”— Edith Sitwell>
(Random House and Merriam-Webster’s Unabridged Dictionaries, American Heritage Dictionary, Oxford English Dictionary
Ken G – March 2, 2004
Reply from Ken Greenwald (Fort Collins, CO - U.S.A.)