Lymphedema: This condition is characterized by the abnormal accumulation of protein-rich fluid in the interstitial tissue, leading to non-pitting edema. It can be primary (inherited) or secondary (acquired) due to surgery, infection, or trauma affecting the lymphatic system.

Scleroderma: A chronic autoimmune disease that affects the skin and connective tissue, leading to fibrosis and non-pitting edema.
Lipedema: A condition characterized by the abnormal growth of fat cells in the legs, leading to non-pitting edema and pain.
Chronic Venous Insufficiency: While often associated with pitting edema, in its chronic stages, it can lead to non-pitting edema due to fibrosis and skin changes.

Thyroid Dysfunction: Both hypothyroidism and hyperthyroidism can cause non-pitting edema, although the mechanisms differ. Hypothyroidism leads to mucin deposition in the skin, while hyperthyroidism can cause increased capillary permeability.
Malignancy: Certain cancers, such as lymphoma or Kaposi's sarcoma, can cause non-pitting edema due to lymphatic obstruction or infiltration.
Infection: Chronic infections like cellulitis or erysipelas can lead to non-pitting edema if not properly treated.

Filarial Elephantiasis: A parasitic infection caused by filarial worms that can lead to severe lymphedema and non-pitting edema, primarily in tropical regions.
Pseudolymphoma: A rare condition that mimics lymphoma but is often benign, can cause non-pitting edema due to lymphatic system involvement.
Sjögren's Syndrome: An autoimmune disorder that primarily affects the glands but can also cause non-pitting edema due to lymphatic involvement.