Inguinal lymphadenitis may be seen with several STDs, especially primary herpes sim-plex infection and lymphogranuloma venereum. The latter is caused by specific strains of C. trachomatis. It may begin as a small genital ulcer, which is frequently unnoticed. Moreoften, the first evidence of lymphogranuloma venereum is a tender swollen inguinal lym-phadenitis, which may suppurate and drain spontaneously if not treated. Primary syphilismay be associated with unilateral or bilateral inguinal lymph node enlargement, but these nodes are not usually tender. Secondary syphilis may be associated with generalized lym-phadenopathy.