Also known as soft chancre and ulcus molle, chancroid is an acute, sexually transmitted infection caused by the bacterium, Haemophilus ducreyi or Ducrey's bacillus.
It is characterized by single or multiple painful ulcers that bleed on contact.
The ulcer or sore begins as a tender papule that becomes a pus-filled, open sore with eroded or ragged edges.
It is soft to the touch, unlike a syphilis chancre that is hard.
The chancroid ulcers are more commonly found in uncircumcised men, on the foreskin or in the groove behind the head of the penis.
The lesions are frequently accompanied by painful, swollen lymph nodes in the region.
In women, lesions may occur on the inner and outer vaginal lips, the vaginal wall or cervix.
Asymptomatic cases in women do happen.
Chancroid is most prevalent in tropical and subtropical developing countries.
It is much less common in temperate zones like the United States.
When it is seen in outbreaks in industrialized nations, it is typically found among foreign travelers, migrant workers and those who are clients of sex workers.
The organism is transmitted by direct sexual contact with the discharges from open lesions or pus from buboes.
The incubation is from 3 to 5 days average, up to 14 days.
The infection is transmissible in the primary lesion from weeks to months without treatment.
Chancroid is treatable with antibiotics (ceftriaxone, erythromycin or azithromycin).
Laboratory diagnosis is based on microbiological culture of the organism on special media.
PCR assays are excellent but not commonly available.
Chancroid ulcers, like other genital ulcers, are associated with an increased risk of HIV infection.