Chronic Venous Insufficiency: This condition is characterized by the veins having problems returning blood from the legs to the heart due to valve issues, leading to blood pooling, which can cause discoloration, swelling, and other symptoms in the lower extremities.

Dependent Edema with Stasis Dermatitis: Prolonged dependency of the legs can lead to fluid accumulation and skin changes, including discoloration.
Lymphedema: A condition where the lymphatic system is impaired, leading to swelling and potentially discoloration of the affected limbs.
Diabetic Dermopathy: A condition associated with diabetes that can cause skin discoloration, typically on the lower legs.

Deep Vein Thrombosis (DVT): Although it may present unilaterally, bilateral DVTs can occur, and missing this diagnosis can be fatal due to the risk of pulmonary embolism.
Cellulitis: A bacterial skin infection that can cause redness, swelling, and discoloration. It requires prompt antibiotic treatment to prevent serious complications.
Acute Limb Ischemia: A sudden decrease in limb perfusion that can cause pain, pallor, pulselessness, poikilothermia, paresthesias, and paralysis. It is a medical emergency.

Erythromelalgia: A disorder characterized by burning pain, heat, and redness in the hands and feet, which can also affect the lower extremities and cause discoloration.
Klippel-Trenaunay Syndrome: A rare congenital malformation that involves blood and lymph vessels, which can cause discoloration and swelling of the affected limb.
Complex Regional Pain Syndrome (CRPS): A condition characterized by chronic pain, inflammation, and hypersensitivity, which can also lead to changes in skin color and temperature of the affected limb.