Chancroid
What is chancroid?
Chancroid is
infection of the genital skin or mucous membranes caused by Haemophilus ducreyi
and characterized by papules, painful ulcers, and enlargement of the inguinal
lymph nodes leading to suppuration. Diagnosis is usually clinical because
culturing the organism is difficult. Treatment is with a macrolide
(azithromycin or erythromycin), ceftriaxone, or ciprofloxacin.
(See also Overview of Sexually Transmitted Infections.)
H. ducreyi is a short, slender, gram-negative bacillus with
rounded ends.
Chancroid occurs
in rare outbreaks in developed countries but is a common cause of genital
ulcers throughout much of the developing world and often acquired by men from
prostitutes. Like other sexually transmitted infections (STIs) causing genital
ulcers, chancroid increases risk of HIV transmission.
H. ducreyi is increasingly being realized to also cause
nongenital skin ulcers in children in certain developing countries
Symptoms and Signs of Chancroid
After an incubation period of 3 to 7 days, small, painful
papules appear and rapidly break down into shallow, soft, painful ulcers with
ragged, undermined edges (ie, with overhanging tissue) and a red border. Ulcers
vary in size and often coalesce. Deeper erosion occasionally leads to marked
tissue destruction.
The inguinal lymph nodes become tender, enlarged, and matted
together, forming a pus-filled abscess (bubo). The skin over the abscess may
become red and shiny and may break down to form a sinus. The infection may
spread to other areas of skin, resulting in new lesions. Phimosis, urethral
stricture, and urethral fistula may result from chancroid.
.
Diagnosis of Chancroid
Clinical evaluation
Sometimes culture or polymerase chain reaction (PCR)
Chancroid is
suspected in patients who have unexplained genital ulcers or buboes (which may
be mistaken for abscesses) and who have been in endemic areas. Genital ulcers
with other causes (see table Differentiating Common Sexually Transmitted
Genital Lesions) may resemble chancroid.
If available, a sample of pus from a bubo or exudate from
the edge of an ulcer should be sent to a laboratory that can identify H.
ducreyi. However, diagnosis is usually based on clinical findings alone because
culture of the bacteria is difficult and microscopic identification is
confounded by the mixed flora in ulcers. PCR testing is not commercially
available, but several institutions have certified tests that are highly
sensitive (98.4%) and specific (99.6%) for H. ducreyi. Clinical diagnosis has a
lower sensitivity (53 to 95%) and specificity (41 to 75%).
Serologic testing for syphilis and HIV and cultures for
herpes should be done to exclude other causes of genital ulcers. However,
interpretation of test results is complicated by the fact that genital ulcers
due to other conditions may be coinfected with H. ducreyi.
Treatment of Chancroid
·
Antibiotics (various)
·
Treatment of chancroid should be started
promptly, without waiting for test results. One of the following is
recommended:
·
A single-dose of azithromycin 1 g orally or
ceftriaxone 250 mg IM
·
Erythromycin 500 mg orally four times a day for
7 days
·
Ciprofloxacin 500 mg orally twice a day for 3
days
·
Patients treated for other causes of genital
ulcers should be given antibiotics that also treat chancroid if chancroid is
suspected and laboratory testing is impractical. Treatment of patients with HIV
coinfection, particularly with single-dose regimens, may be ineffective. In
these patients, ulcers may require up to 2 weeks to heal, and lymphadenopathy
may resolve more slowly.
·
Buboes can safely be aspirated for diagnosis or
incised for symptomatic relief if patients are also given effective
antibiotics.
·
Sex partners should be examined and treated if
they had sexual contact with the patient during the 10 days before the
patient’s symptoms began.
·
Patients with chancroid should have a serologic
test for syphilis and HIV in 3 months.