Updated: Mar 23, 2022
  • Author: Joseph Adrian L Buensalido, MD; Chief Editor: Pranatharthi Haran Chandrasekar, MBBS, MD  more...
  • Print


Chancroid is a bacterial sexually transmitted infection (STI) caused by infection with Haemophilus ducreyi. It is characterized by painful necrotizing genital ulcers that may be accompanied by inguinal lymphadenopathy. [1] It is a highly contagious but curable disease.

Chancroid was once highly prevalent in many areas of the world, but collaborated efforts to increase social awareness and subsequent changes in sexual practices, along with improved diagnosis and treatment options, have eradicated chancroid as an endemic disease in industrialized countries. [2] In 2000, the proportion of chancroid among genital ulcerative diseases (GUD) decreased from 69% to 15%. [3] It remains prevalent in certain underdeveloped regions such as Asia, Africa, and the Caribbean. [3] However, despite the presence of joint STI/HIV control programs, prevention control methods have not been consistently implemented. [2] In these areas, outbreaks occur in cities among workers in the sex trade. Individuals traveling to these high-risk areas are at risk of contracting the disease. In addition, individuals from high-risk areas who travel to other countries to work in the sex industry remain a source of outbreaks in the industrialized world.

Chancroid is a subclass of sexually transmitted genital ulcerative diseases that are of worldwide concern owing to their role as cofactors in the transmission of HIV. [4, 5, 6, 7] Ulcerative STIs penetrate the skin of the external genitalia, colonize the subcutaneous tissue, and produce tissue damage, causing ulceration. [8] Skin abrasion and microtrauma is necessary to penetrate normal skin. The disruption of the mucosal barrier increases the risk for HIV access to the bloodstream and inflammatory cells and serves as a focus for bacterial and viral shedding. [9] A report from the World Health Organization (WHO) estimates that the presence of ulcerative STIs increases the risk for HIV transmission by 10%-50% in women and 50%-300% in men. [10] Multiple genital ulcers, purulent ulcer base, and multiple genital ulcerative lesions increase the likelihood of HIV shedding. [11]

Recently, the etiologic agent of chancroid, H ducreyi, has been isolated among chronic limb ulcers in the Asia Pacific region. H ducreyi should be considered as a cause of chronic limb ulcers in endemic areas [12, 13] and as a common cause of nongenital cutaneous ulcers, mostly in children in tropical countries, especially the South Pacific region. [3]

This photograph shows an early chancroid on the pe This photograph shows an early chancroid on the penis, along with accompanying regional lymphadenopathy. Courtesy of the CDC/Dr. Pirozzi.

See Visual Findings of 9 Sexually Transmitted Infections, a Critical Images slideshow, to help make an accurate diagnosis.



Chancroid is caused by H ducreyi, a small, gram-negative, facultative anaerobic bacillus that is highly infective. It is pathogenic only in humans, with no intermediary environmental or animal host. H ducreyi enters the skin through disrupted mucosa and causes a local inflammatory reaction. It produces a cytocidal distending toxin that appears to be responsible for its destructive effects.

H ducreyi penetrates the skin through breaks in the mucosal barriers and microabrasions on the skin. It produces a cytocidal distending toxin (HdCDT), which causes cell cycle arrest and apoptosis/necrosis of human cells and contributes to the aggravation of ulcers. [14] Phagocytosis by macrophages is also impaired. [15, 16] Other virulence mechanisms include LspA proteins, which have antiphagocytic functions, DsrA map, which facilitates adherence, and an influx transporter that protects H ducreyi from antimicrobial killing. [17, 18, 19]

H ducreyi is transmitted sexually by direct contact with purulent lesions and by autoinoculation to nonsexual sites, such as the eye and skin. The organism has an incubation period of 1 day to 2 weeks, with a median time of 5-7 days. The disease typically begins as a small inflammatory papule at the site of inoculation; within days, the papule may erode to form an extremely painful deep ulceration. Without treatment, the lesions may last weeks to months, and complications such as suppurative lymphadenopathy are more likely. [5, 20, 21]




United States

The Centers for Disease Control and Prevention (CDC) collects data from state health departments in the United States and has published information regarding prevalence of STIs, including chancroid, since 1941, when 3,384 cases were reported. Starting in 1994, a significant decrease in the number of chancroid cases was reported. Only 782 cases were recorded in 1994 and cases steadily decreased over the following years. In 2010, 24 cases were reported from nine different states, [22]  11 cases in 2015, seven in 2016 and 2017, and eight in 2019. [23]

In the past, the disease was considered endemic in several large US cities but is currently seen in sporadic cases associated with low socioeconomic status, poor hygiene, prostitution among sex workers, and drug abuse. The true incidence is difficult to determine and is probably underestimated because of unavailable diagnostic resources and because of the difficulties in culturing H ducreyi, even when laboratory resources are available. [24]


Chancroid is still endemic in many areas of the world. No specific monitoring for this disease exists. The unavailability of diagnostic tests and facilities in resource-limited settings and the difficulty in isolating the organism are recognized factors that contribute to the underreporting of the disease. Therefore, the true incidence of chancroid at present worldwide is unavailable.

Data from the WHO in 1995 suggested that 7 million cases of chancroid existed worldwide. Globally, it has been surpassed by herpes simplex virus (HSV) type 2 as the most common genital ulcerative disease. [1] Chancroid is prevalent in Africa, the Caribbean basin, and Southwest Asia. It is thought to be the most common cause of genital ulceration in Kenya, Gambia, and Zimbabwe. [25, 26, 27] Recently, the prevalence of chancroid decreased substantially in India, the Philippines, Senegal, and Thailand. This development was probably brought by joint programs against HIV/AIDS and related STIs in those areas. [28]

Local outbreaks in various parts of Europe have been reported. The Health Protection Agency in the United Kingdom reported 450 cases of chancroid from 1995-2000. From 1995-2005, 3% of genital ulcer cases from an STI clinic in Paris were due to chancroid. [29] The European Centre for Disease Prevention and Control released a surveillance report on sexually transmitted infections in Europe from 1990-2010, and it was noted that the prevalence of chancroid had decreased dramatically, that some countries had no reported cases, and that some countries even stopped mandatory notifications. [30]


Chancroid is not a lethal disease and does not cause systemic infection, not even in individuals with HIV infection. [31] Even if left untreated, the genital lesion resolves spontaneously within 1-3 months. However, untreated infection can lead to development of painful inguinal lymphadenopathy, which can ulcerate to form buboes in 25% of cases. It is characterized by one or more painful genital ulcers that are associated with unilateral painful inguinal lymphadenopathy in approximately 50% of cases. Left untreated, suppurative bubo formation occurs in approximately 25% of cases, which can progress to spontaneous rupture with formation of a deep nonhealing inguinal ulcer.

Chancroid is easily curable with appropriate antibiotic therapy, although patients with HIV infection require longer courses of therapy. The true impact of the disease lies in the well-known association of genital ulcer disease with increased transmission rates of HIV and other STIs. Previous infection does not confer immunity against the disease, and reinfection is possible. [32] Patients with chancroid and HIV coinfection are more likely to experience multiple chronic genital ulcerations and inguinal lymphadenopathy. [33]

Superinfection of lesions, known as phagedenic chancroid, may lead to widespread disfiguring necrosis and may require surgical excision.


Although no proven racial predilection exists, chancroid is most commonly observed in nonwhite people. This observation is not unexpected, given the prevalence of the disease in areas of Africa, Asia, and the Caribbean. [1]


Chancroid is most commonly observed in nonwhite men who are uncircumcised. A 2006 meta-analysis showed that circumcision is somewhat protective against infection with syphilis and chancroid. [34] Circumcision and its role in HIV and sexually transmitted infection (STI) risk reduction among men who have sex with men (MSM) still needs further investigation. [35] Women represent only 10% of known cases because they are more likely to be asymptomatic carriers.

Chancroid is more commonly identified in individuals of lower socioeconomic status, commercial sex workers, and travelers from endemic areas. [36] According to Benson and Hergenroeder, [36] there have been no reported cases of chancroid among homosexual males, bisexuals, or lesbian females, but recent reports have documented chancroid to occur together with other STIs. [37, 38]


Although it can affect people of any age, chancroid predominantly affects younger sexually active people. The most common age group affected was 21-30 years. [39] Females aged 15-19 years have the highest prevalence among women in the United States, followed by those aged 20-24 years. In males, the highest prevalence is in those aged 20-24 years.