|LGV is caused by serotypes L1, L2, and L3 of the bacteria Chlamydia trachomatis. These serotypes differ from the chlamydial serotypes that cause trachoma, inclusion conjunctivitis, and chlamydial urethritis and cervicitis because they can invade and reproduce in regional lymph nodes.
Lymphogranuloma venereum occurs in 3 stages.
The 1st stage begins after an incubation period of about 3 days with a small skin lesion at the site of entry. It may cause the overlying skin to break down (ulcerate) but heals so quickly that it may pass unnoticed.
The 2nd stage usually begins in men after about 2 to 4 weeks, with the inguinal lymph nodes on one or both sides enlarging and forming large, tender, sometimes fluctuant masses (buboes). The buboes stick to deeper tissues and cause the overlying skin to become inflamed, sometimes with fever and malaise. In women, backache or pelvic pain is common; the initial lesions may be on the cervix or upper vagina, resulting in enlargement and inflammation of deeper perirectal and pelvic lymph nodes. Multiple draining sinus tracts may develop and discharge pus or blood.
In the 3rd stage, lesions heal with scarring, but sinus tracts can persist or recur. Persistent inflammation due to untreated infection obstructs the lymphatic vessels, causing swelling and skin sores.