Pain in the legs is a common occurrence. The most frequent non-disease cause is prolonged standing, walking or running. A person is more likely to get pain in the legs when he or she is not accustomed to strenuous physical activities and ends up overworking the legs, which carry the whole weight of the body. Resting will usually resolve the condition.
In some cases, pain in the legs occurs even while sitting or sleeping. If no strenuous physical activity has preceded the pain, then it could be an indication of some underlying disease or disorder that is causing painful legs. In most such cases, the problem can be traced to a fault in the blood circulation or the nerves in the legs.
Pain in the legs most commonly affects the soles of the feet, the calf muscles, and the knees. Upper leg (thigh) pain is not so common among most people. Other symptoms that might occur along with a general pain in the legs include:
- Cramps: Muscle cramps may occur in the calves and the feet.
- Change in skin color: The skin on the legs may become pale or display a bluish discoloration.
- Darkening skin: A chronic darkening of the skin of the legs may occur.
- Sensory problems: Pain in the legs may either be preceded or followed by numbness or tingling sensations.
- Ulcers: Open sores or ulcers might be associated with the pain in the legs. A common example is foot ulcer.
The presence of these associated symptoms are helpful in diagnosing the cause of the pain in most conditions.
Causes of Pain in the Legs
Most of the causes of painful legs can be traced to some problem in the circulatory or nervous system in the legs. However, other causes may also precipitate the pain.
Reduced Blood Supply
Blood circulation in the legs gets affected if there is a narrowing of the arteries in the legs. Such a condition is known as peripheral arterial disease (PAD). Fatty deposits in the arteries are the most common cause of PAD. It occurs mostly in obese individuals. These deposits can eventually build up to levels that result in the complete obstruction of blood flow through the arteries of the legs, a condition known as acute limb ischemia.
Pain is usually the primary symptom associated with PAD. At first, the pain is associated only with physical exertion. However, the condition may progress to a level where the pain in the legs also occurs when resting or lying down. Relief from pain can sometimes be obtained by lying down with the legs hanging from the side of the bed. However, restoration of blood flow in this condition requires medical intervention.
Weak Blood Vessels
The arteries in the legs are responsible for carrying the blood to the leg muscles, whereas the veins in the legs carry the blood back to the heart. Weakening of the valves in these veins results in pooling of blood in the lower limbs. These weak veins in the legs also acquire a tortuous and bloated appearance, which is easily seen on the overlying skin. This condition, known as varicose veins, can sometimes result in painful calves and legs. The pain associated with varicose veins increases in a standing position. Lying down, walking, or elevating the legs relieves the pain as the pooled blood starts flowing towards the heart.
Obstruction of blood flow in arteries or veins can also occur due to the presence of blood clots in these vessels. Deep veins in the lower part of the legs are usually the sites where such blood clots occur. This condition is also known as deep vein thrombosis (DVT). DVT causes sluggish blood circulation in the lower limbs and can cause pain in the lower legs.
A major risk of DVT is the dislodging and relocation of a blood clot from the veins in the lower limbs to the blood vessels that carry blood between the heart and the lungs. This can result in pulmonary embolism that can quickly turn lethal. In many cases, there may not be any warning symptoms to suggest the presence of DVT. Even pain may be absent. In some cases, a discoloration of the skin in the region of the clot may occur.
Problems with the nerves in the legs can also result in pain. Nerves in the legs might get affected by injuries, B-vitamin deficiencies, or infectious diseases (e.g., shingles). In a condition known as sciatica, the main nerve of the leg (sciatic nerve) becomes inflamed. In this case, the pain begins in the lower back region and subsequently travels down the legs.
The nerves of the legs can also become compressed anywhere along their path of travel. This condition is known as pinched nerve. All these inflammatory nerve conditions in the legs result in peripheral neuropathy, which is characterized by pain, numbness, tingling sensations or weakness in the legs.
One of the most common symptoms of advanced and uncontrolled diabetes is foot pain. Both the blood supply and the nerves in the legs are affected in diabetes. Pain is one of the first symptoms of diabetic foot. Tingling and numbness also occur as the disease progresses. Ulcers or sores may also form in the lower legs and feet. These may then get infected due to the impaired wound healing that is a characteristic feature of diabetes. Limb amputation may be required if the infections progress to form gangrene in the legs.
Women undergoing menopause also frequently report pain and burning sensation in the legs. This may be caused by hormonal changes and vitamin deficiencies. The pain may also be due to varicose veins or deep vein thrombosis. The exact cause, however, remains unclear and needs further investigation.
Children between the ages of 3 and 12 may also report pain in the legs, especially while sleeping. In the absence of any evident causes, these pains have been referred to as growth pains. However, this may not be an appropriate way to describe them since these pains are not always associated with periods of growth spurt. A likely cause is excessive physical activity in young children, who become aware of the painful sensations only when they are resting at night time.
Arthritis of the joints is also another common cause of pain in the legs. This is usually seen in elderly patients. However, younger individuals may also be affected. Rheumatoid arthritis (RA) and osteoarthritis (OA) are the two most common types of arthritis.