Meralgia paraesthetica

Author: Hon A/Prof Amanda Oakley, Dermatologist, Hamilton, New Zealand, December 2016.


What is meralgia paraesthetica?

Meralgia paraesthetica (US spelling, paresthetica) describes pain and/or changed sensation in the skin on the lateral aspect of the thigh. 

Meralgia means pain in the thigh, and paraesthetica refers to burning pain, tingling or itch. Some patients describe itch in the affected area. Meralgia paraesthetica is also called lateral femoral nerve entrapment syndrome.

What is the cause of meralgia paraesthetica?

Meralgia paraesthetica is due to compression or traction of the lateral femoral cutaneous nerve in its pathway from the lumbar plexus, L2-3. This most often occurs under the inguinal ligament, and may be precipitated by:

  • Stretch injury, including after poor positioning after spinal, pelvic or hip surgery  
  • Scar tissue after surgery or trauma
  • Tight clothing, belts and armour
  • Items in a pocket resulting in prolonged or repeated compression
  • Obesity
  • Pregnancy
  • Pelvic tumour
  • Small fibre neuropathy, eg, due to diabetes.

What are the clinical features of meralgia paraesthetica?

Meralgia paraesthetica is characterised by tingling, numbness, burning pain or rarely, intense itch (pruritus) on the outside of the thigh. In about one in five people, it can affect both sides. Symptoms can be intermittent or continuous. They tend to be made worse by standing and walking, and relieved by sitting. When itchy, the itch is unrelieved by scratching, although the scratching and rubbing may be pleasurable. 

In many patients, there are no visible signs. If it is itchy, visible changes often arise from rubbing and scratching the affected area. These include:

  • Scratch marks
  • Hyperpigmentation (brown marks)
  • Hypopigmentation (white marks)
  • Lichen simplex (a type of eczema)
  • Scarring

There may be changed sensation in the affected area of skin, when this is tested for with pinprick, cotton wool or heat and cold, with either numbness or exaggerated sensations being reported. There may be reduced or absent sweating in the affected area.

Lichen simplex associated with meralgia paraesthetica

Investigations

Examination should include extending the thigh posteriorally, as symptoms may be reproduced by stretching the nerve. The pelvic compression test is usually positive (this involves deep palpation in the groin). There should be no signs of muscle weakness. 

Radiology such as ultrasound imaging, X-ray, CT scan or MRI of the hip and pelvic area may be recommended. In many cases, no abnormality is revealed. Other tests may include electromyography (EMG) and nerve conduction study to identify damaged nerves. The diagnosis may be confirmed by relief of symptoms after an injection of local anaesthetic into the entrapment site.

Skin biopsy is rarely performed, and may show reduced intraepidermal nerve fibre density.

Treatment of meralgia paraesthetica

Treatment of meralgia paraesthetica is not always necessary, as symptoms can settle on their own, and it is not always successful.  

  • Avoid wearing tight clothing.
  • If obese, try to lose weight.
  • If painful, medication such as paracetamol or ibuprofen may help.
  • If itchy, cooling lotions or creams as required (camphor and menthol).
  • If itchy, topical steroids are prescribed to treat associated lichen simplex.
  • Local anaesthetic creams may provide temporary relief of symptoms, if they are mild and superficial.
  • Corticosteroid injection into the inguinal ligament may reduce swelling and pain.
  • Local nerve block at the inguinal ligament may provide temporary relief of pain.
  • Amitriptyline or other oral tricyclic at night may help sleep and counteract neuropathic symptoms.
  • Gabapentin, pregabalin or other anticonvulsant are sometimes prescribed.
  • Pulsed radiofrequency  to lateral femoral cutaneous nerve has been reported.
  • Ultrasound-guided lateral femoral cutaneous nerve neurolysis has been reported.
  • Surgical decompression of the pinched nerve may be undertaken in severe cases.

Physical therapy has been reported to be effective.  

 

Related Information

References

  • Grossman MG, Ducey SA, Nadler SS, Levy AS. Meralgia paresthetica: diagnosis and treatment. J Am Acad Orthop Surg. 2001 Sep-Oct;9(5):336-44. Review. PubMed PMID: 11575913. PubMed.
  • Nouraei SA, Anand B, Spink G, O'Neill KS. A novel approach to the diagnosis and management of meralgia paresthetica. Neurosurgery. 2007 Apr;60(4):696-700; discussion 700. Review. PubMed PMID: 17415207. PubMed.
  • Wongmek A, Shin S, Zhou L. Skin biopsy in assessing meralgia paresthetica. Muscle Nerve. 2016 Apr;53(4):641-3. doi: 10.1002/mus.25044. PubMed PMID: 26800390. PubMed.
  • Lee JJ, Sohn JH, Choi HJ, Yang JS, Lee KH, Do HJ, Lee SH, Cho YJ. Clinical Efficacy of Pulsed Radiofrequency Neuromodulation for Intractable Meralgia Paresthetica. Pain Physician. 2016 Mar;19(3):173-9. PubMed PMID: 27008291. Journal.
  • Ahmed A, Arora D, Kochhar AK. Ultrasound-guided alcohol neurolysis of lateral femoral cutaneous nerve for intractable meralgia paresthetica: a case series. Br J Pain. 2016 Nov;10(4):232-237. PubMed PMID: 27867513.PubMed.

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