Left leg swelling is not an uncommon occurrence since it can arise from a collection of different causes. These causes are, however, highly varied and most indicate a potentially serious—or at least problematic—underlying issue. Generally speaking, anything capable of causing left leg swelling has the potential to also make your right leg swell. The distinction of whether one or both legs are swollen can help in the diagnoses since certain conditions are more likely to affect just one leg at a time.
Although there are several possible causes for left leg swelling, they all fall under one of two umbrella categories: edema or inflammation. Edema is a buildup of fluid somewhere in the body. When it builds up in the legs, it is called peripheral edema. “Fluid”, in this context, is a general catch-all term that can include lymphatic fluid, blood, water, or other substances. Inflammation is a type of tissue swelling that arises due to injury or illness as part of the immune reaction.
Causes of Left Leg Swelling: Edema
Sitting or Standing
Sitting down or standing up for a prolonged period causes your body to retain water and can cause temporary swelling. This is most often seen in passengers on long airline flights. For the most part, this kind of swelling is harmless other than a wobbly sensation when you start trying to walk again.
In addition to waste, your kidneys also filter excess water out of the body. If something has impaired the kidney’s ability to function, then this extra fluid has no way to escape the body. Gravity dictates that it passes downwards, hence swelling in the legs. The potential causes of this type of damage are too extensive to get into here but can include infection, cancer, heart attack, direct injury, vascular disorders, and autoimmune conditions.
Congestive Heart Failure
When the heart weakens enough that it cannot pump blood effectively, congestive heart failure will occur. The “congestive” part of the name is from how blood will become congested and pool in various parts of the body without the full strength of the heart to move it around. Blood pooling in the legs, ankles, and feet will cause swelling. Congestive heart failure can arise due to hardened arteries, damage from a heart attack, coronary heart disease, damage from infection, and similar causes.
This is one of the few edema-related causes of left leg swelling that may only affect one leg at a time. A blood clot can form under various conditions, such as if you have a clotting disorder or are immobile for extended periods like after an injury or during a hospital stay. Age, being overweight, smoking, family history, and pregnancy can also affect likelihood of developing a clot. Regardless of why it happens, a blood clot will partially or fully obstruct the vein in your leg. Without anywhere to go, the blood will pool and cause swelling in the affected leg. Pain is also a common symptom, but one that doesn’t always occur. If it does, the pain will start in the calf and feel like an intense cramping or sore sensation. Signs of a blood clot should always be brought to your doctor’s attention since there is the potential for the clot detaching and traveling to one of your organs.
Some drugs, such as aspirin or ibuprofen, can cause fluid retention and result in left leg swelling. The likelihood of this increases with long-term use. Some diabetes and blood pressure pills can also cause edema due to the way they affect circulation and blood flow.
Causes of Left Leg Swelling: Inflammation
Any sufficient injury to the leg, ankle, or foot is capable of producing an inflammatory response. Potential injuries can include breaking the leg or foot, snapping a tendon, or a sprained ankle. These events usually follow a physical injury, accident, or some form of intense exertion. In addition to swelling and redness, the affected leg will have trouble bearing weight and be painful to the touch.
Cellulitis is a type of skin infection that can happen when bacteria (usually staph or strep) get into the skin through a break or cut. It creates a swollen, red area of skin that will be tender and hot to the touch. Although cellulitis can appear anywhere on the body, the lower legs are where it is most commonly seen. Cellulitis is always a concern to doctors since it has the potential to develop into sepsis if the infection reaches the blood stream. If you have a red, swollen, painful rash that is changing rapidly along with a fever, seek emergency medical care immediately.
Arthritis comes in a few different flavors depending on the exact cause and area affected. The general idea remains the same, though: something is affecting the integrity of the joints and your bones are beginning to rub directly against one another. In addition to making mobility painful and difficult, the joints and surrounding area can become swollen. If this happens in the knee or ankle, you can get a swollen left leg as a result. Incidentally, gout is a type of arthritis caused by an accumulation of uric acid crystals in the joints rather than the bones themselves coming into contact.
Treating Left Leg Swelling
Treatment for the left leg relies heavily on the underlying diagnoses. If you believe your left leg swelling warrants treatment, then it is imperative that you bring it to your doctor’s attention along with any associated symptoms in order to get the proper care. Almost every cause of left leg swelling can lead to deformity, disability, impaired quality of life, intense pain and discomfort, or death if left unaddressed. The exact treatment you get will vary wildly depending on the root cause, but a few recurrent elements can be seen:
- Diuretics to make you pee out excess water
- Low-salt diet to help maintain fluid balance
- Compression stockings to force excess fluids out of the leg
- Anti-inflammatory drugs
- Rest, ice, compression, and elevation (RICE for sports injury)
- Lifestyle changes