Disorder or disease	Characteristics of genital lesion	Etiology
Primary syphilis: chancre	Solitary, painless ulcer with indurated border	Treponema pallidum
Secondary syphilis: condyloma latum	Slightly raised or flat, round or oval papules covered by gray exudate	T. pallidum
Genital herpes	Cluster of shallow, small, painful ulcers on a red base	Herpes simplex virus
Chancroid	Painful ulcer with sharp, undermined borders	Haemophilus ducreyi
Venereal warts	Soft, usually painless skin-colored or red papules	Human papillomavirus
Lymphogranuloma venereum: primary stage	Painless papule, shallow erosion, or ulcer; may be multiple or single	Chlamydia trachomatis