Neuralgia is pain that follows the path of a nerve.

See also: Trigeminal neuralgia

Causes of neuralgia include:

• Certain drugs
• Chemical irritation
• Chronic renal insufficiency
• Diabetes
• Infections, such as shingles, syphilis, and Lyme disease
• Porphyria
• Pressure on nerves by nearby structures (for instance, tumors)
• Swelling and irritation (inflammation)
• Trauma (including surgery)

In many cases, the cause is unknown.

Trigeminal neuralgia is the most common form of neuralgia. A related but uncommon neuralgia affects the glossopharyngeal nerve, which provides feeling to the throat.

Neuralgia is most common in elderly people, but it may occur at any age.

• Impaired function of affected body part due to pain, or muscle weakness due to motor nerve damage
• Increased sensitivity of the skin or numbness of the affected skin area (feeling similar to a local anesthetic, such as a Novocaine shot)
• Pain along the path of a specific nerve
• Pain located anywhere, usually on or near the surface of the body
  • In the same location for each episode
  • Sharp, stabbing pain that comes and goes (intermittent) or constant, burning pain

Any touch or pressure is felt as pain. Movement may also be painful.

An exam may show:

• Abnormal sensation in the skin
• Loss of deep tendon reflexes
• Loss of muscle mass
• Lack of sweating (sweating is controlled by nerves)
• Tenderness along a nerve, often in the lower face and jaw and rarely in the temple and forehead
• Trigger points (areas where even a slight touch triggers pain)

A dental examination can rule out dental disorders that may cause facial pain (such as a tooth abscess). Other symptoms (such as redness or swelling) may help rule out conditions such as infections, bone fractures, or rheumatoid arthritis.

There are no specific tests for neuralgia, but the following tests may be done to find the cause of the pain:

• Blood tests to check blood sugar and kidney function
• Magnetic resonance imaging (MRI)
• Nerve conduction study with electromyography
• Spinal tap (lumbar puncture)