What symptom might indicate the presence of thrombophlebitis?

The symptom that indicates the presence of thrombophlebitis is swelling and redness in the affected area. Thrombophlebitis is an inflammatory condition of a vein that often occurs in conjunction with a blood clot. The inflammation results in observable signs such as redness and warmth around the affected area, as well as swelling due to fluid accumulation.

This symptom arises because the inflammation and the clot can obstruct normal blood flow, leading to swelling. As the body reacts to the clot, it sends inflammatory cells to the site, which causes redness. Thus, the presence of swelling and redness is a hallmark indication of thrombophlebitis, helping clinicians to diagnose and determine a treatment path.