Chancroid is a sexually transmitted disease caused by the bacteria Haemophilus ducreyi, which causes painful genital sores.
In developed countries, chancroid is rare, but it is a common cause of genital sores throughout much of the developing world. Because chancroid causes genital sores, people who have it are more likely to become infected with and to spread human immunodeficiency virus (HIV).
Symptoms begin 3 to 7 days after infection. Small, painful blisters form on the genitals or around the anus and rapidly rupture to form shallow, open sores with ragged edges. These sores may enlarge and join together. Occasionally, these sores become deeper and damage other tissues.
The lymph nodes in the groin may become tender, enlarged, and matted together, forming collections of pus (abscesses) called buboes. The skin over the abscess may become red and shiny and may break down and discharge pus from the lymph nodes onto the skin. Sores may form in other areas of the skin.
Doctors suspect chancroid in people with genital sores that have no obvious cause. Usually, doctors take a sample of pus or fluid from a sore and send it to a laboratory to be grown (cultured). However, culturing and identifying these bacteria are difficult, so the diagnosis relies more on symptoms and likelihood of being exposed to the infection.
Specific tests for chancroid are not readily available, but blood tests may be done to exclude other causes, such as syphilis.
Several antibiotics are effective for chancroid. The following may be used:
If buboes are causing discomfort, doctors may make an incision to drain them. This treatment is done only if people are taking antibiotics to control the infection.
Last full review/revision December 2014 by J. Allen McCutchan, MD, MSc