The erythema of syphilis can be necrotic, with round or oval ulcers 1-2 cm in diameter, which are usually painless. The erythema of syphilis, also known as the chancre, is a typical symptom of early syphilis, and the chancre usually appears 2-3 weeks after infection with the spirochete syphilis. It is usually found on the penis, glans, prepuce and tunica in men, and on the labia, perineum and cervix in women. Swelling of the inguinal lymph nodes and enlargement of the lymph nodes in the affected area can also be seen 1-2 weeks after the appearance of the chancre, which usually lasts 3-4 weeks and, if treated aggressively, can resolve in 1-2 weeks, after which a reddish-brown scar may appear or the skin may darken in this area.