Haemophilus ducreyi

Background

• Causes chancroid

Microbiology

• Fastidious Gram-negative bacillus

Epidemiology

• Present worldwide
• Endemic when sex workers, for example, are pressured to have sex with multiple partners despite active genital lesions

Clinical Manifestations

• Presents initially with a papule at the site of inoculation, progressing to pustules, which rupture into painful, purulent, and shallow ulcers
  • Ulcer base often bleeds
  • In men, lesions are more common on the prepuce, coronal sulcus, or penile shaft
  • In women, lesions occur more commonly on external genitalia, but can also occur within the vagina or on the cervix
• Often multiple ulcers
• May have associated painful lymphadenitis, which can drain

Diagnosis

• Culture for Haemophilus ducreyi from swab of lesion, or PCR if available
• Rule out other causes as appropriate with NAAT or PCR

Management

• First-line: ciprofloxacin 500 mg PO once
• Alternatives: erythromycin 500 mg PO tid for 7 days, azithromycin 1 g PO once, or ceftriaxone 250 mg IM once
• Rule out other STIs