Infected inguinal lymph nodes, or lymph nodes in the groin area, cause the lymph nodes to swell. The infection, also called lymphadenitis, causes the lymph nodes to suddenly increase in size. It is also responsible for pain, redness, abcesses and fluid drainage in the area, according to Johns Hopkins Medicine.
Lymphadenitis, including infection in the inguinal lymph nodes, may also be accompanied by fever, sore throat, night sweats, fatigue or weight loss, claims Johns Hopkins Medicine.
Although lymphadenitis can occur in any of the 600 lymph nodes throughout the body, it is most likely to occur in the inguinal lymph nodes when an infection or injury in the foot, leg, groin or genitals is present, states WebMD. The groin area is a common site for swollen lymph nodes. The Merck Manual also states that sexually transmitted diseases such as herpes simplex, chlamydia and syphilis often cause swelling in the inguinal lymph nodes.
Treatment for lymphadenitis may vary depending on the type of infection, says Johns Hopkins Medicine. Possible treatments include antibiotics, medication to treat symptoms such as pain, fever and swelling, or surgery to drain the lymph node if pus is present. Most cases of lymphadenitis go away after treatment.