Topic Editor: Robert Giles, MBBS, BPharm

Review Date: 11/3/2012

Definition

Chancroid is a sexually transmitted disease caused by the bacterium Haemophilus ducreyi. It is characterized by genital ulceration and inguinal adenopathy.

Description

• Chancroid presents with painful genital ulcers followed by painful inguinal lymphadenopathy commonly known as 'buboes'
• The primary causative organism responsible for chancroid is the gram-negative bacillus, H. ducreyi, which is transmitted via infected lesions
• Chancroid is endemic in Africa, Asia, and Latin America. It is rare in the United States and other developed countries
• Chancroid increases the risk of human immunodeficiency virus (HIV) co-infection
• Culturing the causative organism can be difficult, which complicates this diagnosis
• Complete recovery is expected with appropriate antibiotic therapy. There is a low risk of recurrence

Epidemiology

Incidence/Prevalence

• The Centers for Disease Control and Prevention (CDC) report that the incidence of chancroid in the US has declined from 5000 cases in 1987 to 24 cases in 2010
• The World Health Organization (WHO) estimated ~7 million cases, globally, in 1995. The true incidence is unknown due to the limited availability of diagnostic resources
• Chancroid is more common in developing countries in Africa, the Caribbean, and Southwest Asia

• Can occur in all age groups; however, it most commonly affects sexually active young people
• Peak prevalence is seen among females aged 15 to 19 years and males aged 20 to 24 years

Gender

• Chancroid is predominantly seen in uncircumcised males
• Females account for only 10% of cases, however, they may be more likely to be asymptomatic carriers

Race

• There is no evidence of any racial predilection

Risk factors

• Co-infection with other sexually transmitted diseases
• Commercial sex workers
• Low socioeconomic status
• Multiple sexual partners
• Poor personal hygiene
• Residence or travel in an endemic area
• Substance abuse
• Uncircumcised males
• Unprotected sexual intercourse

Etiology

• The causative organism is H. ducreyi, a gram-negative anaerobic bacillus
• Infection typically spreads during sexual contact by the transmission of bacteria from infected lesions to broken skin or mucosa
• Auto-inoculation to non genital areas is also possible

History

• Patients should be questioned about potential exposure to infected individuals
• The incubation period typically ranges from 4-10 days
• Infection begins with the appearance of painful papules which progress to form pustules and subsequently develop into painful genital ulcers
• Women may rarely be asymptomatic, and as such, are potential carriers
• Dysuria or dyspareunia may be seen in women

Physical findings on examination

• Tender erythematous genital papule(s) which rapidly becomes pustular and subsequently erodes into a painful deep ulcer
• Patients may present with single or multiple ulcers, usually 1-2 cm in size
• Friable granulation tissue forms the ulcer base
• Usual infection sites in men include penile shaft, glans, prepuce and meatus
• Usual infection sites in women include labia, introitus, and perianal region
• Painful unilateral or bilateral inguinal lymphadenopathy is evident in 50% of patients
• Development of buboes (significant lymphadenopathy, often with abscesses that spontaneously rupture and drain externally) start 1-2 weeks following ulceration
• Buboes are usually painful and are likely to rupture spontaneously and ulcerate in the absence of adequate antibiotic treatment
• Atypical presentations of lesions occurs especially in HIV or immunosuppressed patients
• A diagnosis of chancroid can be made clinically if a patient has:
• One or more painful genital ulcers
• The ulcers are not due to syphilis or HSV
• The presentation and appearance of ulcers and lymphadenopathy are typical for chancroid

Blood test findings

• H. ducreyi serology
• Serologic testing for H. ducreyi antibodies may be performed however a positive result does not discriminate between current or past infection
• Cross-reactivity to other Haemophilus species makes interpretation of serological tests difficult
• HIV test (Western Blot and ELISA)
• HIV testing should be performed as chancroid infection is an important co-factor in HIV transmission
• Syphillis test
• RPR to rule out syphilis as a differential diagnosis or concomitant infection

Other laboratory test findings

Ulcer swabs:

• Antigen detection
• Antigen testing using monoclonal antibodies against lipooligosaccharide for the outer membrane protein of H. ducreyi is a rapid and sensitive diagnostic technique
• Direct immunofluorescent antibody testing has a high sensitivity (93%), but a low specificity (63%)
• Culture
• Isolation of H. ducreyi on special culture media is necessary for diagnosis, but requires complex media (enriched gonococcal agar and enriched Mueller-Hinton chocolate agar). The sensitivity of culture is 80%, making it unreliable
• Gram stain
• Gram-stain of clinical specimens show typical 'school of fish' arrangement of the organisms. Gram staining has a low sensitivity (5% to 63%) but higher specificity (51% to 99%)
• Herpes Simplex Virus (HSV) PCR or viral culture
• Used to rule out HSV as the cause (or as a concomitant infection)
• Polymerase chain reaction (PCR)
• Amplification of H. ducreyi DNA using PCR has a diagnostic sensitivity of 98% and specificity of 51% to 67%. Simultaneous DNA amplification of H. ducreyi, T. pallidum and Herpes Simplex Virus (HSV) is possible using multiplex PCR (M-PCR) assay
• No FDA approved test is available in the U.S., however, these tests are available in some laboratories

• Tissue biopsy is generally not required for the diagnosis; but can be used to rule out genital herpes or squamous cell carcinoma

• Behçet's disease
• Crohn's disease
• Cutaneous drug reaction
• Drug eruption
• Genital herpes (HSV infection)
• Granuloma inguinale
• Lymphogranuloma venereum
• Pyoderma gangrenosum
• Syphilis

General treatment items

• Antimicrobial therapy
• Since immediate confirmation of chancroid using laboratory testing is not possible, treatment should be initiated upon clinical suspicion of the condition
• Antibiotic therapy aims at curing infection, resolving clinical symptoms, and preventing transmission
• The CDC recommends treatment with any of the following antibiotics. All appear to be similarly effective
• Azithromycin 1 g PO as single dose or
• Ceftriaxone 250 mg IM as a single dose or
• Erythromycin base 500 mg PO tid x 7 days or
• Ciprofloxacin 500 mg PO bid x 3 days
• Ciprofloxacin should not be used during pregnancy. Ceftriaxone may be preferred in pregnant women
• All sexual contacts from within the previous 10 days should be treated for infection
• HIV-positive or immunosuppressed patients may have a prolonged course of illness and usually require an extended antibiotic regimen
• Surgical intervention
• Suppurative lymph nodes >5 cm may require drainage using incision or needle aspiration

Medications indicated with specific doses

Antibiotics

• Azithromycin [Oral]
• Adult Dosing
• Pediatric Dosing
• Ceftriaxone [IM/IV]
• Adult Dosing
• Pediatric Dosing
• Erythromycin [Oral]
• Adult Dosing
• Pediatric Dosing
• Ciprofloxacin
• Adult Dosing
• Pediatric Dosing

Disposition

• The majority of uncomplicated cases can be treated in an outpatient setting

Monitoring

• Patients should be frequently reviewed during the 7-10 days during/after therapy to ensure successful treatment outcomes
• Ongoing review for need of surgical drainage or aspiration of abscess is required
• Patients who fail to respond to appropriate antibiotic therapy should have an alternative diagnosis or concomitant infection considered
• Patients should abstain from sexual intercourse until complete resolution of ulcers
• Counseling and testing are recommended to reduce risk of co-infection with other sexually transmitted diseases, including HIV

Complications

• Acute conjunctivitis
• Balanoposthitis (inflammation of glans penis and foreskin)
• Chronic draining sinus tract
• Gangrene secondary to anaerobic infection as a complication to the primary infection
• Genital scarring
• Inguinal abscess
• Phimosis
• Rectovaginal fistula
• Rupture of buboes
• Urethral fistula

Prevention

• Sexual intercourse with high-risk individuals should be avoided
• Safe-sex practices such as use of condoms, avoiding multiple sexual partners and not sharing sex toys, can significantly reduce the risk of transmission
• Individuals traveling to endemic regions should be counseled regarding the risk of disease

Prognosis

• Prognosis is excellent in the majority of patients
• Symptoms resolve completely with adequate treatment in most cases
• Pain usually subsides within a few days of treatment initiation
• Ulcers usually take 1-2 weeks to heal, with larger ulcers taking longer
• Presence of HIV, immunosuppression, or syphilis co-infection, medication non-adherence and resistant organisms (or incorrect diagnosis) may cause treatment failure
• Approximately 5% of patients experience relapse following treatment

Associated conditions

• Herpes simplex virus infection
• HIV infection
• Syphilis

Pregnancy/Pediatric effects on condition

• There have been no reports of adverse outcomes of chancroid occurring during pregnancy
• Ciprofloxacin is contraindicated in the treatment of pregnant and lactating women

ICD-9-CM

• 099.0 Chancroid

ICD-10-CM

• A57 Chancroid

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