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- A sexually transmitted infection characterized by painful genital ulcerations and inguinal adenopathy
- Uncommon in the United States, present worldwide
- Chancroid is endemic in developing countries, especially sub-Saharan Africa and North India, and is a cofactor for HIV transmission.
- Synonyms: soft chancre; ulcus molle
- <50 cases reported to CDC from 2012 to 2016 (1)
- Actual numbers are likely higher due to lack of testing and underreporting.
Endemic in developing countries; annual estimated global prevalence of 4 to 6 million; actual prevalence is unknown (2).
- More common in
- Sub-Saharan Africa
- Southeast Asia
- Latin America
Etiology and Pathophysiology
- Haemophilus ducreyi enters through abraded skin during sexual activity, attaching to susceptible cells.
- Cytolethal distending toxin facilitates epithelial injury and ulcer formation (3).
- The bacterium contains a fimbria-like protein (flp) operon encoding proteins to promote adherence and pathogenesis.
- Dendritic cells and natural killer cells respond to H. ducreyi. This innate host response determines bacterial clearance versus disease progression.
- H. ducreyi (gram-negative rod) is a uniquely human pathogen.
- One colony-forming unit (cfu) of H. ducreyi results in papule formation in 50% of individuals. 90% develop papule with 100 cfu (3).
- Following exposure, a local tissue reaction generates an erythematous papule that progresses to a pustule in 4 to 7 days. Central ulceration and necrosis follow, leading to the characteristic chancre.
- In addition to genital ulcers, H. ducreyi causes chronic skin ulcerations, particularly in children from developing countries.
- Multiple sexual partners
- Uncircumcised men
- Other genital ulcerative diseases (syphilis, herpes simplex)
Proper condom use and safe sexual behavior
Commonly Associated Conditions
- Syphilis: concurrent in 10% of patients
- Herpes simplex virus (HSV) or HIV infection