Groin lymph nodes can swell due to lymphoma or testicular cancer, or from an infection that occurs in the genitals or legs, according to WebMD. Occasionally, melanoma can also cause the lymph nodes in this area to swell.
Lymph nodes in the groin can swell in response to sexually transmitted infections, explains Healthline. One of these is the bacterial infection syphillis, a condition that causes swollen lymph nodes, rashes on the bottom of the hands and feet, fever and fatigue, states the Mayo Clinic. If syphilis goes untreated, neurological and cardiovascular issues can develop, eventually resulting in death. Genital herpes also causes the lymph nodes in the groin to swell. The genitals itch and form blisters and ulcers during flare-ups. An HIV infection causes not only swollen lymph glands, but fevers, headaches and fatigue as well. As the infection progresses, the symptoms become more serious, including high fevers, chronic diarrhea and weight loss.
The condition lymphadenitis, or lymph node inflammation, also causes lymph nodes in the groin and throughout the body to swell, states Healthline. This is usually as a direct result of an infection or cancer. Lymphadenitis is accompanied by respiratory problems, a sore throat, fever, night sweats and swollen limbs. If the cause of the swelling is infection, treatment isn't necessary, because the body is designed to fight off most infections. Sometimes a biopsy is taken to determine that the swelling isn't caused by a tumor.