Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content + Download Section PDF Listen ++ For further information, see CMDT Part 33-27: Chancroid + Key Features Download Section PDF Listen +++ ++ A sexually transmitted disease caused by the gram-negative bacillus Haemophilus ducreyi Incubation period is 3–5 days + Clinical Findings Download Section PDF Listen +++ ++ Initial lesion at the site of inoculation is a vesicopustule that breaks down to form a painful, soft ulcer with a necrotic base, surrounding erythema, and undermined edges Multiple lesions, started by autoinoculation, and inguinal lymphadenitis often develop Lymphadenitis Usually unilateral Consists of tender, matted nodes of moderate size with overlying erythema Nodes may become fluctuant and rupture spontaneously With lymph node involvement, fever, chills, and malaise may develop Balanitis and phimosis are frequent complications in men Women may have no external signs of infection + Diagnosis Download Section PDF Listen +++ ++ Culturing a swab of the lesion onto special medium + Treatment Download Section PDF Listen +++ ++ A single dose of either azithromycin, 1 g orally, or ceftriaxone, 250 mg intramuscularly, is effective Effective multiple-dose regimens Erythromycin, 500 mg four times daily orally for 7 days Ciprofloxacin, 500 mg twice daily orally for 3 days