Meralgia paraesthetica: numbness and burning in the outer thigh

Meralgia paraesthetica is a nerve condition in which an area of skin on the upper outer thigh becomes painful, numb or tingly. Patient.info describes it as a nerve entrapment syndrome, meaning symptoms caused by a trapped or compressed nerve. The nerve involved is the lateral cutaneous nerve of the thigh, which supplies feeling to the skin of the outer thigh. It passes over the front of the hip bones and under the inguinal ligament, a tough band in the groin, which is where it is most commonly compressed.

NHS Borders describes it as a benign condition in which there is a painful patch of numbness on the side of the thigh, which a person can often draw around with a finger. It does not cause any other symptoms in the legs.

The most common symptoms, according to Patient.info, are burning pain or numbness on the outer side of the upper thigh. Other symptoms include altered sensation in that part of the thigh and tingling or pins and needles.

• Burning pain, numbness or tingling over the outer upper thigh.

• Symptoms made worse by walking and standing, and relieved by lying down with the hip flexed.

• Sometimes aching in the groin, pain in the buttock, or skin that is super-sensitive to heat and light touch.

• In children and younger people, sometimes just pain that limits normal activity.

• No muscle weakness. Patient.info says that if there is weakness the diagnosis is not meralgia paraesthetica.

Patient.info says most cases have no identifiable cause. Known triggers include direct injury to the nerve, such as a seat belt injury from a car accident or injury during medical or surgical procedures such as keyhole hernia repair, and some sports and physical activities. Rarer causes include a neuroma or pelvic or abdominal tumours that compress the nerve, lying curled up for long periods, and diabetes affecting the nerve.

It is more common in men than in women and generally occurs between the ages of 30 and 40, and risk factors include obesity, pregnancy and ascites. NHS Borders says the commonest cause is recent weight gain or pregnancy. Tight belts, corsets and waistbands pressing on the hip area can aggravate it, which is why the advice is to avoid them.

Patient.info says a doctor can make the diagnosis based on your symptoms and examination. Examination might show altered sensation in the skin supplied by the nerve, and the pain can usually be provoked by extending the hip. The doctor will check there is no weakness of the muscles. Often no investigations are needed, although an ultrasound scan may be used if there is concern that a mass in the pelvis is causing the symptoms, and nerve conduction tests are sometimes performed if surgery is planned.

This approach matches NHS Borders guidance, which states that no further tests are required for the typical case.

Patient.info says in most cases only conservative, non-surgical treatments are needed. NHS Borders says most patients do not need any further treatment, and that if the pain is bad enough that you would like a painkiller, there are tablet treatments that your doctor can recommend.

Patient.info says the prognosis is generally good. Pain and pins and needles often resolve with time, but numbness and altered sensation can sometimes remain long term. If there is a serious underlying cause, which is rare, the outlook depends on that cause. NHS Borders warns that meralgia paraesthetica symptoms can persist.

Practical steps such as looser clothing, avoiding long periods of standing, adjusting a seat belt or work belt, and gradual weight management where relevant are low-risk first steps. Patient.info says muscle weakness points away from this diagnosis, so see a doctor promptly if you develop weakness or other new symptoms.

It is usually diagnosed and managed by a GP, with physiotherapy or pain services for persistent cases. NHS Borders guidance indicates referral is rarely required. Private physiotherapy, pain medicine or neurology appointments may be quicker, and steroid injections are performed in pain and orthopaedic services in both sectors.