Chancroid

BASICS

DESCRIPTION

Sexually transmitted infection caused by Haemophilus ducreyi that manifests as painful genital skin ulcerations and inguinal lymphadenopathy

EPIDEMIOLOGY

  • Extremely low incidence in the United States with sporadic outbreaks
  • In underdeveloped countries, a cause of genital ulcer syndrome
  • Probably underreported due to difficulty with definitive diagnosis via culture in developing areas
  • Increases the risk of HIV transmission
  • Seen more commonly in males; females are more likely to be asymptomatic.
  • Sexual contact is the only known route of transmission.
  • If diagnosed in children, sexual abuse should be considered.
  • The United States has seen a 99% decline in cases between 1990 and 2010; since then, the incidence has fluctuated.
  • In 2019, there were eight reported cases.

ETIOLOGY

H. ducreyi, a gram-negative coccobacillus

RISK FACTORS

Increased association with sex workers and individuals involved in drug use

GENERAL PREVENTION

Condom use

PATHOPHYSIOLOGY

  • Transmission suspected via microabrasions sustained during sexual intercourse, allowing the organism to penetrate the epidermis
  • 3 to 10 days later, an erythematous, tender papule develops and progresses to a pustule.
  • The pustule ruptures after 2 to 3 days, leaving a shallow ulcer with a painful, necrotic base with undermined edges.
  • Single or multiple ulcers may be present.
  • Self-inoculation and spread to areas of contact can occur.

COMMONLY ASSOCIATED CONDITIONS

  • Associated with HIV transmission and infection
  • Coinfection with syphilis and human herpes virus may occur (10%).

DIAGNOSIS

HISTORY

  • Diagnosis of chancroid is routinely based on clinical findings after the exclusion of other causes of genital ulcer disease.
  • Males usually present with symptoms referable to an acute, painful genital ulcer.
  • Females may be asymptomatic or present with nonspecific symptoms (dysuria, vaginal discharge, pain with stooling or sexual intercourse, rectal pain, or bleeding).

PHYSICAL EXAM

Classic findings:

  • Extremely painful ulcer with an irregular, undermined border and a gray, necrotic center
    • In males: found on prepuce or coronal sulcus
    • In females: found on the vulva, cervix, or perianal area
  • Painful, unilateral, inguinal lymphadenopathy (bubo) in 50% which may spontaneously drain
  • Extragenital sites are rare and include the inner thigh area, breasts, fingers, and mouth.
  • Globally, H. ducreyi is an emerging cause of nongenital skin ulcers in parts of the South Pacific and Africa.

DIFFERENTIAL DIAGNOSIS

  • Chancroid must be distinguished from the other causes of genital ulcers, including:
    • Syphilis
    • Herpes simplex virus (HSV)
    • Lymphogranuloma venereum
    • Granuloma inguinale
    • More than one of these pathogens may be present in individual cases.
  • Uncommon etiologies include:
    • Trauma
    • Fixed drug eruptions
    • Inflammatory bowel disease
    • Behçet syndrome

DIAGNOSTIC TESTS & INTERPRETATION

Diagnosis is made by clinical findings and exclusion of other causes of genital ulcers.

Initial Tests (screening, lab, imaging)

  • Gram stain from the base of the ulcer: may show short gram-negative coccobacilli in parallel “school of fish” arrangement; not reliable as a screening test as ulcers may contain multiple organisms; routine use is not helpful.
  • Cultures from the ulcer
    • H. ducreyi is a fastidious organism and requires specialized media and technique for successful isolation.
    • Compared with newer amplification techniques, it has been proven to be at most 75% sensitive.
    • Currently the only method routinely available for the definite diagnosis of chancroid
  • DNA amplification
    • A genital ulcer multiplex (GUM) polymerase chain reaction test has been developed for simultaneous amplification of DNA targets from H. ducreyi, Treponema pallidum, and HSV types 1 and 2; offers improved sensitivity when compared with culture
    • This technology is not routinely available.
  • Monoclonal antibody
    • Monoclonal antibody against the outer membrane protein of H. ducreyi using immunofluorescent antibody has also proven to be more sensitive than culture.
    • Could provide easy, rapid, inexpensive, sensitive testing but not available currently
  • Additional testing
    • Evaluation for the common causes of genital ulcer syndrome should be done routinely: culture and PCR for HSV 1 and 2 and dark field examination of ulcer or serologic testing for syphilis performed 7 days after ulcer onset
    • HIV test

TREATMENT

GENERAL MEASURES

Condom use if consenting teen and sexually active

MEDICATION

  • Azithromycin 20 mg/kg (max 1 g) PO, once
  • Ceftriaxone 50 mg/kg (max 250 mg) IM, once
  • Ciprofloxacin 500 mg b.i.d. for 3 days (patients aged >18 years)
  • Erythromycin base 500 mg PO t.i.d for 7 days (≥18 years)
  • One-time directly observed dosing with azithromycin or ceftriaxone is recommended.

ISSUES FOR REFERRAL

Patients should follow up 1 week after diagnosis for monitoring symptom resolution.

SURGERY/OTHER PROCEDURES

Persistent inguinal fluctuant adenitis may be treated with either needle aspiration or incision and drainage.

ADMISSION, INPATIENT, AND NURSING CONSIDERATIONS

Patients should be admitted to the hospital if they are systemically ill and unwell appearing or for concerns of ongoing sexual abuse and safety.

ONGOING CARE

FOLLOW-UP RECOMMENDATIONS

  • Patients should be followed weekly until symptoms resolve
  • Recent sexual partners (within the preceding 10 days) should be treated, even if asymptomatic.
  • If initial HIV and syphilis test results are negative, they should be repeated in 3 months following diagnosis of chancroid.

PATIENT EDUCATION

Prevention: condom use with all sexual activity

PROGNOSIS

  • Symptoms improve within 3 to 7 days.
  • Ulcers heal in 1 to 4 weeks.
  • Lymphadenopathy may take longer to regress; may become fluctuant despite adequate therapy
  • For patients who do not follow the typical course, consider other causes of genital ulcers; noncompliance; presence of a coexisting sexually transmitted disease, especially HIV; and, rarely, presence of a resistant organism.

COMPLICATIONS

  • Draining bubo
  • Coinfection with syphilis and HSV
  • HIV infection

ADDITIONAL READING

CODES

ICD 10

A57.00000 Chancroid

FAQ

Authors

Christina S. Hernandez, MD

Christine S. Cho, MD, MPH, MEd


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