Chancroid: A Less Common Bacterial STD

Chancroid typically causes one or more painful, soft ulcers on the genitals, usually appearing within about a week of exposure, often alongside swollen and tender lymph nodes in the groin. This pain is actually a useful distinguishing detail — syphilis's primary-stage sore (chancre) is classically painless, while chancroid's ulcers characteristically hurt, which is one of the details a doctor uses to help tell the two apart alongside lab testing.

Diagnosis typically involves examining and sometimes culturing a sample from the ulcer, since chancroid isn't always included in a routine blood-based STD panel. It's treatable with a course of antibiotics, and prompt treatment is important both for the individual and because chancroid ulcers can increase the risk of HIV transmission if exposure occurs while an ulcer is present.