Description

• A rare American STD characterized by painful genital ulcerations and inflammatory inguinal adenopathy.
• Although uncommon in the US, it is found worldwide.
• Chancroid is endemic in developing countries, especially sub-Saharan Africa, and is a cofactor for HIV transmission.

Epidemiology

• <50 cases reported to CDC in 2004–2010
• Actual numbers are considered higher due to lack of testing and thus underreporting.

• Endemic in developing countries; annual estimated global prevalence of 4–6 million, but actual prevalence is unknown due to lack of testing
• Thought to be extremely common in:
  • Sub-Saharan Africa
  • Southeast Asia
  • Latin America

Risk Factors

• Multiple sexual partners
• Uncircumcised men
• Prostitutes may be carriers.
• Patients presenting with other genital ulcerative diseases
• HIV

General Prevention

Condom use should be demonstrated and promoted.

Pathophysiology

• Involves entry of the bacteria through abraded skin, followed by attachment of the bacteria to susceptible cells
• Cytotoxin is secreted, which may play a role in epithelial injury and ulcer formation.
• The bacterium contains a fimbrialike protein (flp) operon that encodes proteins that contribute to adherence and pathogenesis.
• Dendritic cells and natural killer cells respond to Haemophilus ducreyi, and this innate host response determines bacterial clearance versus disease progression.

Etiology

Haemophilus ducreyi (gram-negative rod) thought to be strictly a human pathogen

Commonly Associated Conditions

• Syphilis: Concurrent in 10% of patients
• Herpes simplex virus (HSV) or HIV infection