Chancroid Workup

Updated: Mar 23, 2022
  • Author: Joseph Adrian L Buensalido, MD; Chief Editor: Pranatharthi Haran Chandrasekar, MBBS, MD  more...
  • Print

Laboratory Studies

No laboratory testing is able to immediately confirm the diagnosis of chancroid. [4]

A definitive diagnosis of chancroid is based on isolation of H ducreyi on special media, but such tests are not readily available in many centers. In addition, lesion culture is inaccurate owing to the fastidious nature of the organism, with a sensitivity of less than 80%. [45, 46]

The nucleic acid amplification test (NAAT) is a multiplex PCR assay that yields a high detection rate, [47] although, no molecular assays have been cleared by the Food and Drug Administration (FDA) for use in the United States. [48]

The role of polymerase chain reaction (PCR) in rapid detection of H ducreyi is promising and may supersede culture in diagnosis. [45, 49, 50]


Other Tests

When possible, every patient with chancroid should be tested for the other common STIs (syphilis, HSV, gonorrhea, chlamydia) and HIV.



Needle aspiration and/or incision and drainage are recommended for buboes that are fluctuant and tender. As with other abscesses, incision and drainage may be a superior technique for preventing abscess recurrence.


Histologic Findings

Gram stain of the ulcer exudates may reveal short, plump, gram-negative rods in the classic school of fish appearance. Ulcer biopsy should reveal three distinct zones. The most superficial zone contains erythrocytes, fibrin, necrotic tissue, and neutrophils. The next zone consists of marked endothelial cell proliferation and many thrombosed new blood vessels. The deepest layer is characterized by a dense infiltrate of plasma and lymphoid cells.