Chronic Venous Insufficiency: This condition is characterized by the inability of veins to return blood from the legs to the heart due to valve issues, leading to swelling, skin thickening (induration), and potentially ulcers. It's a common cause of leg induration, especially in older adults or those with a history of deep vein thrombosis.

Lipedema: A condition involving the abnormal growth of fat cells in the legs, leading to swelling and induration. It's more common in women and can be mistaken for obesity or lymphedema.
Lymphedema: Swelling and induration due to the accumulation of lymph fluid, often resulting from surgery, infection, or congenital conditions affecting the lymphatic system.
Erythema Induratum (Bazin Disease): A form of panniculitis that presents with recurring nodules or indurations on the calves, typically in young women. It's associated with tuberculosis.

Deep Vein Thrombosis (DVT): Although DVT typically presents with acute swelling and pain, chronic or recurrent DVT can lead to induration due to chronic inflammation and scarring. Missing this diagnosis can lead to pulmonary embolism, a potentially fatal condition.
Malignancy (e.g., Lymphoma, Kaposi's Sarcoma): Certain cancers can cause leg induration, either through direct invasion or metastasis. Early detection is crucial for effective treatment.

Scleroderma: A chronic autoimmune disease that can cause skin thickening and induration, among other systemic symptoms.
Necrobiosis Lipoidica: A rare skin condition characterized by necrotic lesions that can lead to induration, often associated with diabetes.
Panniculitis (other forms): Besides erythema induratum, other forms of panniculitis (inflammation of the subcutaneous fat) can cause leg induration, including alpha-1 antitrypsin deficiency and factitial panniculitis.