Chancroid

Chancroid is an ulcerative STD that is most common in developing countries and is rare in the United States and Western Europe. In the United States, it is associated with prostitution and with the use of crack cocaine.
The causative organism, Haemophilus ducreyi, a gram-negative Streptobacillus, is fastidious and requires specific conditions for culture.
Chancroid occurs as a mixed infection with syphilis or herpes simplex in 10% of cases.
Clinical infection is more common in men than in women.

Clinical Manifestations ⬆ ⬇

The location of lesions depends on the site(s) of inoculation.
In men, the prepuce, balanopreputial fold, and the shaft of the penis are the typical sites.
In women, lesions are noted on the labia majora, posterior commissure, or perianal area.
Extragenital lesions have been described.
The incubation period is 25 days.
The earliest manifestation is a papule, which becomes a pustule and ulcerates.
Fully developed lesions are painful, with undermined borders and peripheral erythema (Figs. 28.21 and 28.22).
Borders are not indurated.
There may be satellite ulcers.
Tenderness and pain are common.
Unilateral or bilateral inguinal adenopathy (buboes) may be present.

Diagnosis ⬆

The diagnosis is often made based on the clinical appearance.
A negative darkfield examination, syphilis serologic testing, and HSV cultures help to exclude other diagnoses.
Obtaining a culture is difficult.
A Gram stain shows characteristic “schools of fish” or “Chinese characters.”
Polymerase chain reaction may help in making a diagnosis.

Differential Diagnosis

Herpes Simplex

Chronic HSV

Primary Syphilis

The borders are indurated not undermined, and the lesion is generally painless.

Management

Drug Therapy

Azithromycin 1 g PO in a single dose or
Ceftriaxone 250 mg IM in a single dose or
Erythromycin 500 mg PO four times daily for 7 days or
Ciprofloxacin 500 mg PO twice daily for 3 days
Pregnant women and HIV-infected patients should be treated with erythromycin.
Symptomatic improvement usually occurs in 3 days; objective improvement is seen in 7 days.
Complete healing may take more than 2 weeks.
HIV testing should be performed on all patients and repeated 3 months later if negative.

Management

Doxycycline 100 mg PO twice daily for 3 weeks minimum.
Alternative regimen (and in pregnant women): erythromycin 500 mg PO four times daily for 3 weeks minimum.
Buboes may need to be aspirated or incised and drained.

Points to Remember

Chancroid is rare in the United States, but epidemics have been described in crack cocaine users.
Always test for coinfection with HIV, syphilis, and HSV.