What is a characteristic feature of a chancre in syphilis?

A chancre, which is the primary lesion of syphilis caused by the bacterium Treponema pallidum, is characterized by being nonpainful and indurated. This induration refers to the hardening of the surrounding tissue, which is a typical finding in primary syphilis. The chancre usually appears as a solitary, raised sore at the site of infection, most commonly on the genitalia, but it can also occur on other mucosal surfaces or skin.

The nonpainful nature of the chancre distinguishes it from lesions caused by other sexually transmitted infections, as many of these conditions typically present with painful sores or lesions. The description of the chancre as indurated is essential, as the firm border helps in identifying it as a specific feature of this stage of syphilis. The absence of pain, coupled with the characteristic induration, aids clinicians in recognizing this stage of the disease and differentiating it from other potential diagnoses.