Chronic lower leg edema is a persistent, abnormal swelling of the leg that is present for at least 3 months. Blood carrying oxygen, proteins, and nutrients to the lower extremities is released into the interstitial space surrounding capillaries. Fluid is then reabsorbed into either the venous (bloodstream) or the lymphatic system and returned to the upper body to carry cell waste for disposal. Fluid balance is maintained by this circulation. When an imbalance occurs as a result of venous disease, lymphatic disease, or obesity, the drainage of fluid is impaired, resulting in swelling or edema.
There can be many causes of chronic edema but more often involve venous disease and cardiac failure including hypertension, chronic venous insufficiency, severe varicose veins, history of deep vein thrombosis, phlebitis, leg trauma, obesity, immobility, cancer, post-thrombotic syndrome, cardiac disease, renal disease, and medications.
Chronic edema effects the viability and structure of the skin. Early skin changes involve skin pitting, seen as indentions in the skin that often go unrecognized. Symptoms can also include spider veins in the ankle area, varicose veins and dermatitis.
As the disease progresses without treatment, more apparent and severe skin changes take place, including hemosiderin staining due to venous insufficiency. This can result in ulcerations, including venous stasis ulcers with fluid leakage and infection.
Over time, gradual hardening of lymphatic system tissues can take place as waste products accumulate due to the lymphatic system failing to drain the excess fluid. If left untreated, chronic edema of the leg can result in cellulitis, a common bacterial infection of the skin and subcutaneous tissue that is often difficult to treat. Reoccurrence of cellulitis is common and can lead to more severe complications, including death.