Chancroid is an ulcerating infection caused by Haemophilus ducreyi, a Gram-negative coccobacillus. Until the middle of the 20th century, the condition was endemic in most parts of the world. Indeed it was one of the original venereal diseases named in the English and Welsh VD Act of 1916 (along with gonorrhoea and syphilis).
Cases have declined significantly since then — this is thought to be partially due to changes in the sex industry. Compared to 1900 there are now more job opportunities for poor urban women and for those who do enter the sex industry there has been an improvement in their working lives and health. Chancroid relies on frequent partner change to spread in a community and because its symptoms are painful, when medical attention is available, people seek help rather than have more sex.
It is now very rare in the UK, with only a few dozen cases diagnosed in UK genitourinary medicine clinics in 2002. In the same year, 69 cases were reported in the US. In post-industrial nations, most cases occur in people with a history of sexual contact with someone from a country where chancroid is more common. Sporadic outbreaks do occur, however, and tend to be in groups where sex is exchanged for drugs. Such outbreaks are usually rapidly brought under control by thorough partner notification. Chancroid is still endemic in many countries of South and West Africa and in parts of South East Asia. For example, in 2000 a study in Botswana found that 26% of genital ulcers were caused by H. ducreyi.
Because of the popularity of international travel and the increasing role of crack cocaine in the European sex industry, there is still a chance of coming across the condition.
Presentation of Chancroid
Unlike many STIs the majority of people with chancroid have symptoms, although some women can be asymptomatic.
Chancroid is most likely to present as genital ulceration. Two to ten days after acquisition a papule appears. This then ruptures leaving an ulcer. Most people have more than one lesion and they are typically deeper than herpetic ulcers with an irregular edge and a sloughy base. They are soft and painful, which distinguishes them from the chancres of primary syphilis. Size varies from a few millimetres to several centimetres. Co-infection with herpes simplex virus or Treponema pallidum pallidum can alter the appearance. In people with HIV, the ulcers can be unusually persistent and more likely to be extragenital.
Cervical lesions can present with dyspareunia; vulval lesions can cause dysuria; and rectal lesions can cause rectal pain or bleeding. Unlike in herpes, a flu-like prodrome does not occur.
Auto-inoculation to other sites such as the thighs and hands can occur.
One or two weeks following the appearance of the ulcers, most people develop regional lymphadenitis. This is usually inguinal, unilateral and painful. The lymph node can necrose and ulcerate through the skin.
Complications of Chancroid
Ulcers can lead to tissue destruction and bleeding if they erode into blood vessels. Secondary infection can delay healing and contribute to tissue damage. Sometimes fistulae form which are slow to heal. The lesions usually heal with scarring and this can result in phimosis or anal stenosis.
Haematogenous or lymphatic dissemination to distant sites does not occur.
Chancroid is a cofactor for the transmission of HIV.
Diagnosis of Chancroid
The diagnosis should be suspected in anyone with typical symptoms who has had sex with someone from a country where chancroid is common. There are very few other causes of tender, fluctuant inguinal node enlargement. It is essential to try to confirm the diagnosis, however, due to the implications for partner notification.
H. ducreyi can be grown but this needs specialized transport and culture media which are not widely available.
Gram-stained microscopy of material taken from an ulcer or bubo can identify the Gram-negative coccobacilli that often cluster in a ‘school offish’ pattern.
Unfortunately, due to the numerous other organisms seen in genital ulcers, microscopy has low sensitivity and specificity.
PCR tests are becoming more widely available and are the most sensitive method — check with your local lab whether they can provide this service.
Treatment of Chancroid
Azithromycin 1 g p.o. once is very effective, although follow-up is essential since treatment failures can occur. Resistance to azithromycin is currently very unusual but will undoubtedly become more common as its use increases.
Buboes can be aspirated or incised and drained under antibiotic cover.
Other management of Chancroid
The patient should be offered a check for other STIs, including other causes of genital ulceration, and HIV. The patient should be followed up at about 5 days and again if the ulcers have not healed. If the ulcers have not healed, it might be because they were very large, the person could have HIV, the H. ducreyi might be resistant to azithromycin or it might not be chancroid.
Give advice about reducing risk of acquiring STIs in the future.
All sexual contacts since 2 weeks prior to onset of ulceration should be seen and examined. The person should be advised to avoid sex until the lesions have completely healed.