A 34-Year-Old Woman With Knots on Her Leg and Reddening Skin

Padma Chitnavis, MD; Mary Maiberger, MD


May 19, 2023


Thrombophlebitis is a diagnostic finding that can be a harbinger of systemic disorders that result in hypercoagulable states, especially when taken into consideration within the appropriate clinical context and not simply disregarded as an isolated finding. Thrombophlebitis is the inflammation of a vein caused by the presence of a thrombus. Several factors contribute to thrombus pathogenesis, which are categorized broadly in Virchow's triad as hypercoagulable states, vascular stasis/irregular flow, and endothelial damage.[1]

Physical examination is often the most useful aid to the diagnosis of thrombophlebitis because it can frequently present as tender, palpable, linear, and sometimes branching cords or nodules, especially when involving more superficial vessels. The primary morphology can sometimes be confused with other cutaneous entities, including panniculitides and cutaneous granulomatous disorders (eg, sarcoidosis, cutaneous polyarteritis nodosa). In these instances, skin biopsy can be useful.[2]

If superficial thrombophlebitis is suspected upon initial examination, it must be distinguished from superficial phlebitis. Duplex ultrasonography allows the clinician to identify the presence of a thrombus within a superficial vein and to rule out thrombus extension into deeper tissues (eg, deep venous thrombosis [DVT]). Venography can also be performed to determine the scale and depth of thrombus extension.[3]

The differential diagnosis for primary conditions that manifest with thrombophlebitis is broad and includes several different categories of disorders, including the following [4,5]:

Laboratory tests should be obtained in order to identify a causative disorder, if suspected. These include complete blood cell counts, prothrombin time, aPTT, basic metabolic panel, serum protein C and protein S levels, antithrombin level, and antiphospholipid antibodies panel (lupus anticoagulant, anticardiolipin, anti-beta-2-glycoprotein I). Workup for occult malignancy should be performed if history, review of systems, or physical examination reveals any concern.


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