Phlegmasia cerulea dolens

Phlegmasia cerulea dolens (literally: painful blue edema) is an uncommon severe form of deep venous thrombosis which results from extensive thrombotic occlusion (blockage by a thrombus) of the major and the collateral veins of an extremity. It is characterized by sudden severe pain, swelling, cyanosis and edema of the affected limb. There is a high risk of massive pulmonary embolism, even under anticoagulation. Foot gangrene may also occur. An underlying malignancy is found in 50% of cases. Usually, it occurs in those afflicted by a life-threatening illness.

This phenomenon was discovered by Jonathan Towne, a vascular surgeon in Milwaukee, who was also the first to report the "white clot syndrome" (now called heparin induced thrombocytopenia [HIT]). Two of their HIT patients developed phlegmasia cerulea dolens that went on to become gangrenous.