- Published on
Infectious Disease and Microbiology – Chancroid
Chancroid is a sexually transmitted infection characterized by painful genital lesions that may progress to ulceration. The primary lesion typically begins as a tender papule or pustule measuring 2–20 mm in diameter, which rapidly becomes an excavated ulcer with undermined, ragged, or irregular edges.
In the United States, chancroid is rare and usually occurs in localized outbreaks. Only a small number of cases are reported annually, although underdiagnosis is possible. Globally, the disease remains prevalent in parts of Africa, Asia, and Latin America, and in lower socioeconomic populations in the United States.
Risk factors include multiple sexual partners, sexual contact with an infected partner, and travel to or sexual contact with persons from endemic regions. Chancroid increases both transmission of and susceptibility to HIV infection. Approximately 10% of individuals with chancroid acquired in the United States are coinfected with Treponema pallidum (syphilis) or herpes simplex virus (HSV).
The causative agent is Haemophilus ducreyi, a small, fastidious gram-negative rod. The incubation period ranges from 1 to 14 days.
Clinically, tender papules develop at the site of inoculation and become pustular, eroded, and ulcerated within 1–2 days. Multiple lesions may coalesce to form a large ulcer exceeding 2 cm in diameter. Approximately 40% of patients develop tender inguinal lymphadenopathy (“buboes”), which may suppurate and rupture spontaneously. The combination of painful genital ulcers and suppurative inguinal lymphadenopathy is characteristic.
Diagnosis is often based on clinical and epidemiologic features, but misdiagnosis is common; laboratory confirmation is important. Definitive diagnosis requires isolation of H. ducreyi on specialized culture media, which are not widely available. Culture has approximately 80% sensitivity. Polymerase chain reaction (PCR) testing has higher sensitivity (about 95%) but is not widely available and is not FDA approved in many settings. Diagnosis also requires exclusion of syphilis (negative dark-field examination or serology performed more than 7 days after ulcer onset) and genital herpes (negative clinical and laboratory findings). All patients should be tested for HIV at diagnosis.
For specimen collection, the lesion may be gently abraded to obtain exudate, which can be applied to slides for microscopy when indicated. Histopathologic examination typically shows superficial purulent exudate and mononuclear cell infiltrates in the dermis; neutrophil infiltration may be reduced in HIV-infected patients.
The differential diagnosis includes genital herpes, syphilis, acute HIV infection, lymphogranuloma venereum, granuloma inguinale (donovanosis), mycobacterial or fungal infections, parasitic infections, venereal warts, scabies, molluscum contagiosum, folliculitis, and plague. Noninfectious causes such as malignancy, trauma, fixed drug eruptions, Behçet syndrome, and dermatitis herpetiformis should also be considered.
First-line treatment options include azithromycin 1 g orally as a single dose or ceftriaxone 250 mg intramuscularly as a single dose. Alternative regimens include ciprofloxacin 500 mg orally twice daily for 3 days or erythromycin base 500 mg orally four times daily for 7 days. Ciprofloxacin is contraindicated in pregnancy and lactation. Some isolates with intermediate resistance to ciprofloxacin or erythromycin have been reported. Sexual partners within 10 days preceding symptom onset should be evaluated and treated with the same regimen.
Fluctuant buboes may require needle aspiration through intact skin or incision and drainage; incision and drainage may reduce the need for repeated procedures.
Patients should be reexamined within 3–7 days to assess clinical improvement. Complete healing depends on ulcer size; larger ulcers may require more than two weeks to resolve. Healing may be slower in uncircumcised men with subpreputial ulcers. Failure to improve may indicate incorrect diagnosis, coinfection (e.g., syphilis), reinfection, antimicrobial resistance, noncompliance, or HIV infection. Patients with initial negative HIV or syphilis tests should be retested approximately three months later.
Complications include secondary ulcers, draining fistulas following lymph node rupture, and increased risk of HIV transmission. Education on safe-sex practices is essential to prevent recurrence and transmission.
Chancroid is a sexually transmitted infection characterized by painful genital lesions that may progress to ulceration. The primary lesion typically begins as a tender papule or pustule measuring 2–20 mm in diameter, which rapidly becomes an excavated ulcer with undermined, ragged, or irregular edges.
In the United States, chancroid is rare and usually occurs in localized outbreaks. Only a small number of cases are reported annually, although underdiagnosis is possible. Globally, the disease remains prevalent in parts of Africa, Asia, and Latin America, and in lower socioeconomic populations in the United States.
Risk factors include multiple sexual partners, sexual contact with an infected partner, and travel to or sexual contact with persons from endemic regions. Chancroid increases both transmission of and susceptibility to HIV infection. Approximately 10% of individuals with chancroid acquired in the United States are coinfected with Treponema pallidum (syphilis) or herpes simplex virus (HSV).
The causative agent is Haemophilus ducreyi, a small, fastidious gram-negative rod. The incubation period ranges from 1 to 14 days.
Clinically, tender papules develop at the site of inoculation and become pustular, eroded, and ulcerated within 1–2 days. Multiple lesions may coalesce to form a large ulcer exceeding 2 cm in diameter. Approximately 40% of patients develop tender inguinal lymphadenopathy (“buboes”), which may suppurate and rupture spontaneously. The combination of painful genital ulcers and suppurative inguinal lymphadenopathy is characteristic.
Diagnosis is often based on clinical and epidemiologic features, but misdiagnosis is common; laboratory confirmation is important. Definitive diagnosis requires isolation of H. ducreyi on specialized culture media, which are not widely available. Culture has approximately 80% sensitivity. Polymerase chain reaction (PCR) testing has higher sensitivity (about 95%) but is not widely available and is not FDA approved in many settings. Diagnosis also requires exclusion of syphilis (negative dark-field examination or serology performed more than 7 days after ulcer onset) and genital herpes (negative clinical and laboratory findings). All patients should be tested for HIV at diagnosis.
For specimen collection, the lesion may be gently abraded to obtain exudate, which can be applied to slides for microscopy when indicated. Histopathologic examination typically shows superficial purulent exudate and mononuclear cell infiltrates in the dermis; neutrophil infiltration may be reduced in HIV-infected patients.
The differential diagnosis includes genital herpes, syphilis, acute HIV infection, lymphogranuloma venereum, granuloma inguinale (donovanosis), mycobacterial or fungal infections, parasitic infections, venereal warts, scabies, molluscum contagiosum, folliculitis, and plague. Noninfectious causes such as malignancy, trauma, fixed drug eruptions, Behçet syndrome, and dermatitis herpetiformis should also be considered.
First-line treatment options include azithromycin 1 g orally as a single dose or ceftriaxone 250 mg intramuscularly as a single dose. Alternative regimens include ciprofloxacin 500 mg orally twice daily for 3 days or erythromycin base 500 mg orally four times daily for 7 days. Ciprofloxacin is contraindicated in pregnancy and lactation. Some isolates with intermediate resistance to ciprofloxacin or erythromycin have been reported. Sexual partners within 10 days preceding symptom onset should be evaluated and treated with the same regimen.
Fluctuant buboes may require needle aspiration through intact skin or incision and drainage; incision and drainage may reduce the need for repeated procedures.
Patients should be reexamined within 3–7 days to assess clinical improvement. Complete healing depends on ulcer size; larger ulcers may require more than two weeks to resolve. Healing may be slower in uncircumcised men with subpreputial ulcers. Failure to improve may indicate incorrect diagnosis, coinfection (e.g., syphilis), reinfection, antimicrobial resistance, noncompliance, or HIV infection. Patients with initial negative HIV or syphilis tests should be retested approximately three months later.
Complications include secondary ulcers, draining fistulas following lymph node rupture, and increased risk of HIV transmission. Education on safe-sex practices is essential to prevent recurrence and transmission.
0 Comments
