The general cause of a leg swell is the additional fluid that grows in the lower extremity tissues. If this waving remains and is indented by a finger it is termed as Edema Pitting. There can also be other less usual causes for this problem that include Eosinophilic fasciitis and scleroderma which result in the thickness of the skin. In these cases, the leg swapping is characterized by non-pitting edema. Some of the main causes of pitting edema include Cellulitis, Baker Cyst, Congestive Heart Failure, Eosinophilic-Fasciitis, Kidney Failure, Cirrhosis of the Liver, and Scleroderma.
In Cellulitis, the skin and the tissues under it get bacterially infected. As the area is initially it ever gets larger, swells and becomes reddish.
The leg swelling due to baker cyst is a result of the protruding of knee joint fluid behind the knee cap.
In congestive heart failure, the heart is not properly able to perform its blood pumping function to the different organs of the body. This in result effects all the body organs directly or indirectly as reduction in blood supply causes the different parts of the body to work improperly and some vital parts of the body like kidneys do not work properly and effect the other parts of the body.
Eosinophilic-Fasciitis is a specific subtype of white blood cells. Their number should not increase the normal biological limit set by nature. Fascia is the name of a tissue under the skin to cover under tissues surface. In Eosinophilic-Fasciitis skin infection and thickening occurs and the fascia underneath swells result in legs waving.
In case of kidney failure, the body starts holding fluid, which results in increased blood pressure. That leads to piling up of harmful wastes in the body. The body's ability to make red cells at a normal rate is seriously effected. In addition, due to these wastes build up different parts of the body swell.
In Cirrhosis of the liver the liver is not able to function properly and can not eliminate the toxic substances in the body which start depositing in the different parts of the body including legs which can result in swelling of legs.
The last cause, which can result in leg swelling, is Scleroderma in which body's own immune system attacks its tissues. That results in scar tissues and swelling of that part of the body where they attack and that may be any part of the part where they attack.