Oedema is the medical term for fluid retention in the body. This fluid build-up causes affected tissue to become swollen. The swelling can occur in one particular part of the body, such as the ankles or feet, or it can be more general. This is usually the case with oedema that occurs as a result of certain health conditions, such as heart failure or kidney failure.
When oedema occurs in the feet or ankles, it may be the result of localised processes such as injuries and infections, or it may be caused by systemic conditions (conditions that affect the entire body, such as obesity or pregnancy). Diseases of the joints, such as arthritis, can also affect the joints of the ankle and foot, leading to swelling of the involved areas. Treatments for swollen ankles and swollen feet depend on the particular cause, but anti-inflammatory medications are often used to manage the pain associated with strains and sprains.
Swelling symptoms depend on the underlying cause, and can range from a painless increase in foot and ankle diameter (size) to changes of skin colour and texture. Other symptoms may include warm skin and ulceration with pus leakage.
There are many causes of swollen feet and ankles. Some of the more common include:
- Extended periods of standing or walking
- Medications (side effects): many medications, such as steroids and NSAIDs, have a side effect of fluid retention that manifests as swelling.
- Injury: any trauma to the foot or ankle (usually sprains or fractures) can result in swelling.
- Diseases: heart disease, liver disease, kidney disease (all of these diseases can influence fluid mobilisation in the body by physical, metabolic and electrolyte-water interactions).
- Infection: any infection, either localised (abscess) or diffuse (cellulitis).
- Lymphedema: swelling due to lymph vessel or lymph node blockage of lymph fluid.
- Blood clot(s): blockage of blood vessels (usually venous) that cause fluid to leak out of vessels into tissue .
Treatment of swollen feet and ankles depends heavily on an accurate diagnosis of the underlying cause(s). However, the condition can often be helped by elevating the legs above the heart while lying down. You should avoid sitting or standing without moving for prolonged periods of time, or wearing clothing that might constrict blood flow in the upper legs. Exercising the legs will help the fluid work back into the veins and stimulate lymphatic channels so that the swelling goes down. A low-salt diet may also help reduce fluid retention and decrease ankle swelling.