Chronic Venous Insufficiency (CVI): This condition is characterized by the veins having problems returning blood from the legs back to the heart due to valve issues or blockage, leading to edema, often unilateral and more pronounced in one leg due to gravitational effects and valve incompetence.

Deep Vein Thrombosis (DVT): A blood clot in the deep veins of the leg can cause swelling, pain, and discoloration, typically affecting one leg.
Lymphedema: This condition involves the abnormal collection of protein-rich fluid in the interstitial tissue, leading to swelling of one or more extremities, which can be primary (inherited) or secondary (due to surgery, infection, or trauma).
Cellulitis: A bacterial skin infection that can cause redness, swelling, and warmth, usually affecting one leg.

Compartment Syndrome: A serious condition resulting from increased pressure within a muscle compartment, which can lead to muscle and nerve damage. It is characterized by the "5 Ps": pain, pallor, pulselessness, paresthesia, and paralysis.
Phlegmasia Cerulea Dolens: A severe form of DVT that causes significant swelling and cyanosis of the affected limb, which is a medical emergency.
Necrotizing Fasciitis: A life-threatening infection that affects the tissue beneath the skin and surrounding muscles and organs, requiring immediate medical attention.

Klippel-Trenaunay Syndrome: A rare congenital condition characterized by port-wine stains, varicose veins, and bony and soft tissue hypertrophy, leading to edema and other complications in the affected limb.
Lipedema: A chronic condition characterized by the abnormal growth of fat cells in the legs, leading to swelling and pain, which is often mistaken for obesity or CVI.
Filarial Lymphedema (Elephantiasis): A condition caused by parasitic worms transmitted through mosquito bites, leading to severe swelling and disfigurement of the affected limb, more common in tropical regions.