Chancre should not be confused with canker sore.
A chancre [1] is a painless genital ulcer most commonly formed during the primary stage of syphilis.[2] This infectious lesion forms around 21 days after the initial exposure to Treponema pallidum, the gram-negative spirochaete bacterium causing syphilis, but can range from 10 to 90 days.[2] Without treatment it may persist for two to six weeks before healing.[2] Chancres transmit syphilis through direct physical contact. These ulcers usually form on or around the anus, mouth, penis and vulva.
Chancres are also associated with the African trypanosomiasis (sleeping sickness), surrounding the area of the tsetse fly bite.
Similarities between the conditions chancre and chancroid:[3]
| Chancre | Chancroid | |
|---|---|---|
| Caused by Treponema pallidum infection | Caused by Haemophilus ducreyi infection | |
| Typically painless | Typically painful | |
| Typically single lesion | Typically multiple lesions | |
| Regional bilateral lymph node enlargement | Regional unilateral lymph node enlargement | |
| Typically exudes serum | Typically has a grey or yellow purulent exudate | |
| Hard (indurated) base with sloping edges | Soft base with undermined edges | |
| Heals spontaneously within three to six weeks | Requires antibiotic treatment |
The word "chancre" (in French pronounced as /ʃɑ̃kʁ/) means "little ulcer" in Old French. Related to the English "canker", they both come from the Latin cancer, meaning "crab",[5] which is a translation from the Greek word καρκίνος (karkínos), also meaning "crab".[6]