Haemophilus ducreyi can cause painful, nonindurated genital ulcers, termed soft chancres, at times accompanied by painful inguinal lymphadenopathy. Although common in some developing countries, it had become rare in the United States. In 1987, however, its incidence had increased tenfold during the previous 10 years, and drug use and sex-for-drugs were shown to be important risk factors (Schmid and co-workers, 1987). Importantly, the infection is a high-risk co-factor for HIV and syphilis transmission (Centers for Disease Control and Prevention, 2002d).

Diagnosis by culture is difficult because appropriate media are not widely available. Instead, clinical diagnosis is made when typical painful genital ulcer(s) are darkfield negative and herpesvirus tests are negative.

Recommended treatment in pregnancy is azithromycin, 1 g orally as a single dose; erythromycin base, 500 mg orally four times daily for 7 days; or ceftriaxone, 250 mg in a single intramuscular dose (Centers for Disease Control and Prevention, 2002d).