- • Tender papule develops into a pustule after an
incubation period of 4–7 days; the pustule ruptures within
a few days to produce a nonindurated, painful ulcer with a purulent
base and undermined or ragged borders.
- • Unilateral tender inguinal adenopathy may progress
to a bubo (fluctuant lymph node mass) that spontaneously ruptures
or requires drainage.
- • Isolation of the causative
organism, Haemophilus ducreyi, by special culture media.
Chancroid is a sexually transmitted genital ulcer disease caused
by Haemophilus ducreyi, a small, fastidious,
gram-negative rod. Worldwide, chancroid
incidence exceeds that of syphilis in many developing countries.
In 1997, the World Health Organization estimated that there were
six million new cases of chancroid. Based on polymerase chain reaction
(PCR) assays, chancroid prevalence has been shown to range from
23% to 56% in endemic areas (Africa, Asia, and
the Caribbean). In the United States and western Europe outbreaks
are episodic. The infection is also up to 25 times more prevalent
in men than in women, a difference recognized in both naturally
occurring and experimental disease in humans and macaques. In fact,
although controversial, it has been suggested that women may be asymptomatic
carriers or reservoirs of the infection.
Although chancroid is uncommon in North America, outbreaks occur
in the inner cities of the United States. The most recent of these
began in the late 1980s in an outbreak attributed to sexual behavior
associated with crack cocaine use and sex in exchange for drugs
or money. The number of cases peaked in 1988, when 5001 cases were
reported. Since then, the number of cases has sharply declined to
an all-time low of 30 cases reported in 2004. Currently chancroid
is rare in the United States and Canada.
The reasons for the decline in reported chancroid cases are multifactorial
and not completely understood. There did not appear to have been
a decline in sexual risk behavior or crack cocaine use in the at-risk
populations. Improved provider education and awareness, condom promotion, partner
notification and treatment programs, and the addition of chancroid
treatment to the syndromic management of genital ulcers all may
have played a role. Previous localized chancroid outbreaks appear
to have been controlled by identifying and treating reservoir core
groups such as commercial sex workers.
A major constraint to understanding chancroid epidemiology has
been the lack of sensitive and specific diagnostic tests. The organism
is fastidious and difficult to culture. When diagnosis is based
on clinical criteria alone, the infection is likely to be grossly
over-reported in some circumstances and under-reported in others.
The development of sensitive and specific PCR assays for H ducreyi, it is hoped, will correct
the problem of misdiagnosis in the future.
Chancroid has been shown to facilitate HIV transmission by providing
both a portal of entry and an exit for the virus. In other words,
chancroid increases both the transmissibility and the susceptibility
of HIV and may do so by ...