Swelling in the feet, ankles or other areas of the body occurs in approximately 50 percent of people with lupus.1
Swelling (edema) causes
The kidneys are one of the organs most commonly damaged in lupus. In healthy people, the kidneys work to:
- Maintain the correct quantity and type of body fluids
- Remove waste from the blood
- Help control blood pressure by regulating certain hormones2
When the inflammation of lupus attacks the kidneys, it prevents the kidneys from working well. This can cause a variety of problems, including fluid build-up and high blood pressure. When fluid builds in the body it is called edema, which means swelling.3
Swelling caused by lupus usually appears in the feet, ankles, legs, and eyelids, but may occur across the whole body. Edema can be a sign of a more serious condition, lupus nephritis. Lupus nephritis most often begins to affect people with lupus between ages 20 and 40.2
Edema in people with lupus may also be caused by taking non-steroidal anti-inflammatory drugs (NSAIDs) to control pain.
Lupus-related edema diagnosis
Your doctor will ask you about your diet, the drugs you are taking, and if you have other symptoms related to edema, such as blood in the urine, foamy urine, or an increased need to urinate at night.2
Your doctor may also order blood tests and a urinalysis to determine what is causing your swelling.
Reducing the salt (sodium) in your diet is one of the first things your doctor will recommend to control edema. The taste buds can be retrained in less than one to two weeks to adjust to lower-sodium foods. Fresh herbs, salt-free spice blends, citrus, and flavored vinegar are some tasty alternatives to salt.4
Foods that are higher in sodium are packaged foods, snack foods, restaurant food (especially fast food), lunch meats, cheese, dressings, sauces, bread, and soda.
Controlling high blood pressure, if you have it, may also help reduce swelling in the lower legs and abdomen. Common lupus treatments, including steroids, antimalarials, and immunosuppressants, help control the inflammation that causes kidney damage, which in turn can help control edema.