Associated symptoms
In addition to burning, other sensory disturbances can occur, such as numbness or formication. The skin can react very sensitively to touch – even to clothing. Furthermore, the affected thigh or the entire leg can swell in connection with a thrombosis, for example.
Furthermore, the skin colour of the thigh may fade or show redness. In some cases, thrombosis also results in an increased vein pattern. This means that the superficial veins protrude more and can be seen through the skin.
If the burning pain is caused by herpes zoster, it can also show itself in the form of reddened nodules and blisters and can be accompanied by a reduced general condition and fever. In some cases there is muscle loss and thus weakness in the affected leg. The nerve damage to the extremities – polyneuropathy – can also lead to muscle weakness.
In addition, there is often a reduction in reflexes, limited sweat secretion (for example on the feet) or even flaccid paralysis. Burning pain and numbness are typical symptoms of polyneuropathy – one of the most common nervous diseases. The so-called peripheral nervous system is affected, i.e. the nerves that lie outside the spinal cord and brain (central nervous system).
In addition, temperature sensation disorders can also occur. In most cases, however, these diseases begin at the ends of the extremities (feet or hands) and then spread upwards. The peripheral nerves can be damaged by various underlying diseases.
The diseases include diabetes, alcohol abuse, cancer and infectious diseases. However, feelings of numbness in the thigh can also occur if there is a thrombosis in the upper thigh or pelvis. Stinging pain in the thigh is more likely to be a sign of so-called window dressing disease (peripheral arterial occlusive disease or PAD).
This is a partial or total occlusion of arterial vessels in the pelvic area that causes pain in the thigh. Initially, the pain is only felt during longer walking distances, but the complaints disappear again during pauses in walking. If the disease is not treated, the pain-free walking distances become shorter and shorter until they can finally be felt at rest. The stabbing pain is sometimes accompanied by burning pain. Sometimes the complaints are also described as cramping.
Classification by localization
Burning pains on the outer thigh speak for the so-called Meralgia paraesthetica. This is the constriction of a nerve (nervus cutaneus femoris lateralis) which supplies the skin on the outer thigh sensitively. The area of supply extends from the groin to just above the knee, whereby a burning sensation is also felt in this area.
If this nerve is pinched – for example by wearing too tight clothing or during pregnancy – it becomes irritated and can then cause the burning pain. Herpes zoster (shingles) can also cause discomfort on the outer thigh, but then the lower back up to the feet can also be affected. On the inside of the thigh there is a deep leg vein, the femoral vein.
This vein can become blocked by a blood clot (thrombosis) after long periods of immobilisation of the legs – for example after an operation or a long-haul flight. Veins are there to transport the blood from the extremities and other parts of the body back to the heart. However, if the femoral vein is blocked, blood remains in the veins and causes severe pain, especially in the area of the thrombosis.
If nerves are additionally irritated, burning pain can also occur. The area is also often reddened and swollen. Burning pain at the front of the thigh is usually nerve pain caused by the femoral nerve.
This runs through the inguinal ligament and can be trapped there. This often leads to shooting and sometimes burning pain in the thigh. If it is a spinal or muscle problem at the level of the lumbar spine, the pain often radiates from the lower back into the thigh.
If the N. cutaneus femoris anterior is affected, superficial burning of the skin on the front thigh occurs. A burning sensation on the thigh when sitting is a rather unusual phenomenon, but can have several potential causes. For example, sore muscles may be involved.
However, this would not only occur specifically when sitting, but would also be present elsewhere. Furthermore, a circulatory disorder due to a kinked artery or a nervous sensation, for example due to a spinal stenosis or something similar, would be conceivable. The time it takes for the burning sensation to disappear after straightening up could be a decisive indication.
In any case, this is a finding that requires clarification and should be presented to a doctor. A burning sensation on the thigh during sport can basically have three major causes, two of which are obvious. – Primarily, it could be an injury that you have sustained during sports.
Torn muscle fibres caused by overloading or unintentional overstretching are prominent examples. – Furthermore, it would be conceivable that the muscles are overstressed due to excessively strenuous training, which causes the muscles to overstretch. Then too much lactic acid (lactate) accumulates within the muscle, which cannot be broken down and causes a burning sensation during the intensive load and shortly afterwards.
This process is also known as muscle ache. – Last but not least an ischemic pain could be imagined, the cause of which is usually not clear. For various reasons, the working muscles may be insufficiently supplied with blood and oxygen, which can manifest itself as a burning sensation on or in the thigh. If the muscle cells are undersupplied over a longer period of time, cell death can quickly occur and, if the area is large, the limb can also die. Therefore a doctor should be consulted quickly.
