thumb|Chancres on the face and hand. Up-left: upper lip, Up-right: lower lip, Bottom-left: right upper eyelid, Bottom-right: thumb.
thumb|right|Chancre on the underside of the penis
A chancre ( ) is a painless genital ulcer most commonly formed during the primary stage of syphilis. 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.
- Both originate as pustules at the site of inoculation, and progress to ulcerated lesions
- Both lesions are typically 1–2 cm in diameter
- Both lesions are caused by sexually transmissible organisms
- Both lesions typically appear on the genitals of infected individuals
Differences from chancroid
{| class="wikitable"
|+ Differences between the conditions chancre and chancroid
|-
! 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
|}
- Chancres can occur in the pharynx as well as on the genitals. Not to be confused with condylomata lata, which is seen in secondary syphilis.
Etymology
The word "chancre" () means "little ulcer" in Old French. Related to the English "canker", they both come from the Latin cancer, meaning "crab", which is a translation from the Greek word καρκίνος (karkínos), also meaning "crab".
See also
- Primary cutaneous histoplasmosis