Superficial thrombophlebitis
Superficial thrombophlebitis is a thrombosis and inflammation of superficial veins presenting as a painful induration (thickening) with erythema, often in a linear or branching configuration with a cordlike appearance. Superficial thrombophlebitis is due to inflammation and/or thrombosis, and, less commonly, infection of the vein.
Source: Wikipedia — Superficial thrombophlebitis (CC BY-SA 4.0)