Are there any distinctive differences between chancroid and herpes?

Genital ulcers: Herpes and chancroid cause genital ulcers (also syphilis). In the us, genital herpes is the most common. A definitive diagnosis of chancroid is a little tricky b/c test not widely available. Having both a painful genital ulcer and tender swelling in the groin suggests the diagnosis of chancroid (in setting of negative syphilis and herpes testing). Hiv test should also be done. See md for eval.

Yes, but overlap: Genital herpes usually causes multiple genital ulcers that start as blisters, whereas chancroid almost always is a single lesion, rarely two. There are several other differences as well, but still there is overlap: some cases of herpes look exactly like chancroid. In most areas of the world, herpes is a hundred times more common than chancroid. There's been no chancroid in the US for many years.