What causes ankle swelling?

By Jonathan Cluett, M.D.

What causes ankle swelling?

Swelling of the lower leg and ankle is a common problem. Determining the cause of ankle swelling is the first step to finding effective treatment. Once the cause of the ankle swelling is determined, effective treatment can be initiated.

Answer: Ankle swelling causes the accumulation of fluid within the ankle joint or in the soft tissues surrounding the ankle. Common causes of ankle swelling include: 

Traumatic Injury
A traumatic injury, such as an ankle sprain or a broken ankle, is the most common cause of ankle swelling. Patients almost always remember the particular injury, but occasionally even subtle injuries can also lead to ankle swelling. Also, stress fractures can occur around the ankle joint leading to swelling. 

Gout
Gout is due to the accumulation of uric acid crystals within the fluid of your ankle. Uric acid is a substance produced as part of digestion. In order to properly digest food and rid our body of waste, our bodies produce substances such as uric acid to transport waste material. People with gout abnormally accumulate uric acid crystals within joints, leading to inflammation and swelling. 

Ankle Arthritis
Ankle arthritis is much less common than degenerative changes in other joints. However, ankle arthritis can occur and can be quite painful. Ankle arthritis is most common in patients with rheumatoid arthritis or in patients with a previous injury to the ankle joint. 

Infection
Infection is an unusual cause of ankle swelling. Infections can either occur in the soft tissues around the ankle joint (cellulitis) or in the joint itself (septic joint). Infections can often be treated with medications alone, but may also require surgery. 

Vascular Obstruction
Numerous problems with blood flow can impair normal circulation and lead to swelling around the ankles. The most common cause of vascular obstruction is a blood clot, also known as a DVT. This type of vascular problem usually occurs in one leg (not both), and leads to swelling of the soft-tissues throughout the foot and ankle. The swelling can also extend further up the leg. 

Peripheral Edema
Peripheral edema is also a circulation problem, but is seen in both legs, not just one. Lower extremity edema can be due to aging of the veins leading to chronic swelling, as well as other conditions that can place pressure on the leg veins. These conditions include pregnancy, obesity, and varicose veins.