Once limited mainly to the tropics, chancroid, also called soft chancre or soft sore, is becoming more common in North America. Caused by the Haemophilus ducreyi bacterium, chancroid is characterized by painful, persistent ulcers on the genitals and enlarged lymph nodes in the groin.
Three to 7 days after infection, small blisters form on the genitals and around the anus. These quickly rupture to form shallow ulcers, which may enlarge and join together. At the same time, the lymph nodes in the groin may become tender, enlarged, and matted together, forming a shiny, red-surfaced abscess. Pus is dis- charged when the skin of the abscess breaks down. Left untreated, the abscess may leave deep scars.
The sores are the basis of the diagnosis of chancroid, but this may need to be conﬁrmed by examining a sample of the pus under a microscope. The problem is that the chancroid does not always look like its textbook description and may be mistaken for an ulcer caused by syphilis or genital herpes. Chancroid, syphilis, and genital herpes are the most common causes of sexually transmitted skin lesions.
As with other bacterial STDs, antibiotics are the treatment of choice but, in this case, the drug must be injected every 6 hours for at least 7 days. It is some- times necessary to remove pus from an abscess with a syringe. For at least 3 months after that, the person must be monitored by a doctor to make sure the infection is cured. It is important to ﬁnd and examine the person’s sexual part- ners so they can be treated if necessary.
A person with a chancroid ulcer who is exposed to HIV (human immunodeﬁ- ciency virus) is more likely to become infected.