• rss
  • facebook
  • twitter
  • linkedin


Chancroid, or soft chancre, is a sexually transmitted disease caused by Haemophilus ducreyi, a gram-negative bacillus. It is relatively uncommon in the United States, but is the most common cause of genital ulcers in Africa. The incubation period is 3 to 7 days. The lesion begins as a soft, red papule. Within 1 to 2 days, it becomes pustular, eroded, and ulcerated. The ulcer is usually 1 to 2 cm in diameter, painful, and covered by a yellowish or gray exudates; it bleeds easily when scraped. The edges of the ulcer are ragged and undermined. Chancroid does not have a vesicular stage. In males the ulcer is typically located on the distal penis, but may occasionally occur in the urethra and anal orifice. In females, the lesions tend to be localized to the vulva but can also occur in the vaginal, perianal area, and cervix. Painful inguinal lymphadenopathy and over-riding erythema is associated with chancroid in nearly half of all cases in males, less often in female cases. The lymph nodes become fluctuant, can spontaneously rupture, and drain pus. Systemic symptoms can occur but are rare.

Differential Diagnosis: Chancroid can be distinguished from cutaneous anthrax in the following manner.



Cutaneous anthrax

*Lesion is located in the anogenital area

* Lesion is a painful ulcer without eschar

* Lesion lacks vesicular stage


* Ulcer is painless

* Lesion is located on exposed parts of the body

*Lesion has a vesicular stage

*Ulcer and eschar are surrounded by characteristic non-pitting edema



Search ACP Smart Medicine

Search this point-of-care decision support tool today. A free benefit of ACP membership.

Have questions about the new ABIM MOC Program?

Have questions about the new ABIM MOC Program?

ACP explains the ABIM requirements and offers many free solutions to earn MOC points.

One Click to Confidence - Free to members

One Click to Confidence - Free to members ACP Smart Medicine is a new, online clinical decision support tool specifically for internal medicine. Get rapid point-of-care access to evidence-based clinical recommendations and guidelines. Plus, users can easily earn CME credit. Learn more