A troubling symptom with many potential causes, unexplained swelling can be caused by an allergic reaction to foods, medications, or environmental substances, especially when the swelling involves the face, lips, and throat. Medical conditions affecting the heart, kidneys, or liver can sometimes cause swelling in various areas of the body. Autoimmune diseases such as lupus or arthritis may cause unexplained swelling of the joints. Any unexplained swelling should always be reported to a doctor for further medical evaluation and individualized treatment.

Any unexplained swelling involving the face, lips, or tongue should be reported to a doctor immediately, especially if these symptoms are accompanied by a rash or difficulty breathing. This combination of symptoms may indicate a potentially life-threatening allergic reaction known as anaphylaxis. Emergency medical care is necessary in cases of anaphylaxis, as a lack of oxygen to the brain and other internal organs can cause death within a matter of minutes.

Liver or kidney disease can cause unexplained swelling throughout the body, particularly in the hands, feet, and abdomen. Certain cardiac conditions, such as congestive heart failure, may also involve this symptom. Blood tests and other diagnostic testing methods, including x-rays or ultrasound, may be needed in order to properly diagnose these conditions.

Arthritis is often the cause of unexplained swelling involving the joints. Other symptoms may include pain and difficulty moving the affected joints. Over-the-counter or prescription medications may be used to help control these symptoms. Autoimmune diseases such as lupus may lead to swelling of the joints as well as other parts of the body. In some cases, swelling may be caused by a physical injury, sunburn, or poor nutritional habits.

Lymph node infections or certain forms of cancer may cause swelling in the neck, armpits, or groin. Prescription antibiotics are generally effective at treating infections. If cancer is suspected, a variety of medical tests may be needed in order to accurately diagnose the cause of the swelling.

Thyroid disease, the use of certain medications, or standing for prolonged periods of time may sometimes lead to the development of unexplained swelling. This symptom can also be caused by having too much sodium in the diet. Although swelling does not usually indicate the presence of a serious illness, it is important to always report any unusual symptoms to a doctor so that an accurate diagnosis can be obtained and proper medical treatment can begin.