infectious diseases
Chancroid
Diagnosis of Chancroid
History and physical examination Sometimes culture or polymerase chain reaction (PCR) Chancroid is suspected in patients who have unexplained genital ulcers or buboes (swollen, tender lymph nodes that may become suppurative or form abscesses) and who are or have been in endemic areas. Genital ulcers from other causes (see table) may resemble chancroid. 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. 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 identifyH. ducreyi. PCR testing is not commercially available, but several institutions have certified tests that are highly sensitive (98.4%) and specific (99.6%) forH. 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 withH. ducreyi. 