(See also Overview of Sexually Transmitted Infections Overview of Sexually Transmitted Infections Sexually transmitted infections (STIs), also termed sexually transmitted diseases or STDs, can be caused by a number of microorganisms that vary widely in size, life cycle, the diseases and... read more .)
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 (eg, South Pacific islands [ 1 General reference 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... read more ]).
1. Mitjà O, Lukehart SA, Pokowas G, et al: Haemophilus ducreyi as a cause of skin ulcers in children from a yaws-endemic area of Papua New Guinea: A prospective cohort study. Lancet Glob Health 2:e235–41, 2014. doi: 10.1016/S2214-109X(14)70019-1
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 Phimosis and Paraphimosis Phimosis is inability to retract the foreskin. Paraphimosis is entrapment of the foreskin in the retracted position; it is a medical emergency. Phimosis is normal in children and typically resolves... read more , urethral stricture, and urethral fistula may result from chancroid.
Diagnosis of Chancroid
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 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
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.
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