Recurrent vs. Recurring

Is there a difference between recurring and recurrent? As is so often the case with nearly identical words, the answer is "yes and no." Both words are most commonly used in the sense "happening time after time." But recurrent, the more commonly-used of the two, tends to appear more often in medical contexts, as in “recurrent fevers” or “recurrent cancer.” It also has a specialized anatomical sense, "running or turning back in a direction opposite to a former course,” as in “a recurrent artery,” that recurring does not share. There are certainly circumstances in which either recurrent or recurring could be used; pain or needs might be described as either recurrent or recurring. But even in such cases, there may be subtle differences which you may wish to pay attention to. Recurrent tends to suggest a coming back of something that has existed before, whereas recurring often implies simply a repeated occurrence.