The calf is actually the lower leg from knee to ankle. It is made up of two muscles: the gastrocnemius (more superficial) and the soleus (deep muscle.) Causes of calf swelling can be injuries, infections, specific conditions (standing for extended lengths of time) and certain diseases. Whether the inflammation happens in one or both calves may help to isolate the cause. Also, if the swelling started after a fall or injury, this can determine cause.
Calf injuries occur from trauma such as motorcycle accidents, falls or sports-related accidents and might include a deep calf bruise, muscle strain, lower leg fracture or wounds. All might lead to swelling.
You can also injure the calf from overuse and repetitive activities such as running or jumping. According to the American Academy of Orthopaedic Surgeons, compartment syndrome is when inflammation or blood causes an area to become too full, causing pain and swelling. You can have acute compartment syndrome, which is serious and potentially life-threatening, or chronic compartment syndrome, which is less severe. Chronic compartment syndrome worsens with increased activity and improves with rest. Both types typically affects the leg and calf area.
A calf muscle strain will lead to swelling. A strain means that one of the two calf muscles has torn to some extent. A mild tear may not lead to swelling symptoms, but a moderate to severe tear will definitely cause swelling, according to according to Sports Injury Clinic's website.
In particular, cellulitis is a bacterial infection that often affects the lower legs, according to the Mayo Clinic. It is characterized by swollen, red skin that may be warm to the touch. It could be superficial only or spread to tissues and the lymph system. Cellulitis may start out in the leg and travel to other body parts as well.
Conditions and Diseases
A condition such as deep vein thrombosis (DVT) or a blood clot can form in the calf area. This can cause redness, swelling, pain, heat or tenderness in the area. DVT is a serious condition that must be monitored and treated by medical professionals, according to the National Heart Lung and Blood Institute.
Also diseases such as diabetes or congestive heart failure can lead to swelling in the lower legs. You would probably see inflammation in both legs if either of these conditions was the cause.
Standing on your feet too long on an unforgiving surface such as concrete can cause calf swelling. If you are pregnant or overweight, standing for long periods of time might result in lower leg inflammation. It is also possible to have calf edema (swelling) that is a complication of another medical condition such as lymphedema (lymphatic system blockage) or due to age, states Healthline.com.