Meralgia paresthetica is a condition characterized by tingling, numbness and burning pain in your outer thigh. The cause of meralgia paresthetica is compression of the nerve that supplies sensation to the skin surface of your thigh.
Tight clothing, obesity or weight gain, and pregnancy are common causes of meralgia paresthetica. However, meralgia paresthetica can also be due to local trauma or a disease, such as diabetes.
In most cases, you can relieve meralgia paresthetica with conservative measures, such as wearing looser clothing. In severe cases, treatment may include medications to relieve discomfort or, rarely, surgery.
Meralgia paresthetica occurs when the lateral femoral cutaneous nerve — which supplies sensation to the surface of your outer thigh — becomes compressed, or pinched. The lateral femoral cutaneous nerve is purely a sensory nerve and doesn’t affect your ability to use your leg muscles.
In most people, this nerve passes through the groin to the upper thigh without trouble. But in meralgia paresthetica, the lateral femoral cutaneous nerve becomes trapped — often under the inguinal ligament, which runs along your groin from your abdomen to your upper thigh.
Common causes of this compression include any condition that increases pressure on the groin, including:
- Tight clothing, such as belts, corsets and tight pants
- Obesity or weight gain
- Wearing a heavy tool belt
- Scar tissue near the inguinal ligament due to injury or past surgery
Nerve injury, which can be due to diabetes or seat belt injury after a motor vehicle accident, for example, also can cause meralgia paresthetica.
Pressure on the lateral femoral cutaneous nerve, which supplies sensation to your upper thigh, might cause these symptoms of meralgia paresthetica:
- Tingling and numbness in the outer (lateral) part of your thigh
- Burning pain on the surface of the outer part of your thigh
These symptoms commonly occur on one side of your body and might intensify after walking or standing.
In most cases, your doctor can make a diagnosis of meralgia paresthetica based on your medical history and a physical exam. He or she might test the sensation of the affected thigh, ask you to describe the pain, and ask you to trace the numb or painful area on your thigh. Additional examination including strength testing and reflex testing might be done to help exclude other causes for the symptoms.
To rule out other conditions, your doctor might recommend:
- Imaging studies. Although no specific changes are evident on X-ray if you have meralgia paresthetica, images of your hip and pelvic area might be helpful to exclude other conditions as a cause of your symptoms.If your doctor suspects a tumor could be causing your pain, he or she might order a CT scan or MRI.
- Electromyography. This test measures the electrical discharges produced in muscles to help evaluate and diagnose muscle and nerve disorders. A thin needle electrode is placed into the muscle to record electrical activity. Results of this test are normal in meralgia paresthetica, but the test might be needed to exclude other disorders when the diagnosis isn’t clear.
- Nerve conduction study. Patch-style electrodes are placed on your skin to stimulate the nerve with a mild electrical impulse. The electrical impulse helps diagnose damaged nerves. This test might be done primarily to exclude other causes for the symptoms.
- Nerve blockade. Pain relief achieved from anesthetic injection into your thigh where the lateral femoral cutaneous nerve enters into it can confirm that you have meralgia paresthetica. Ultrasound imaging might be used to guide the needle.
For most people, the symptoms of meralgia paresthetica ease in a few months. Treatment focuses on relieving nerve compression.
Conservative measures include:
- Wearing looser clothing
- Losing excess weight
- Taking OTC pain relievers such as acetaminophen (Tylenol, others), ibruprofen (Advil, Motrin IB, others) or aspirin
If symptoms persist for more than two months or your pain is severe, treatment might include:
- Corticosteroid injections. Injections can reduce inflammation and temporarily relieve pain.
- Tricyclic antidepressants. These medications might relieve your pain.
- Gabapentin (Gralise, Neurontin), phenytoin (Dilantin) or pregabalin (Lyrica). These anti-seizure medications might help lessen your painful symptoms.
Rarely, surgery to decompress the nerve is considered. This option is only for people with severe and long-lasting symptoms.