PHN is persistent nerve pain following an episode of shingles and considered to be due to nerve damage. It is more frequent with increasing age and may affect any part of the body. The condition is caused by the varicella zoster virus and is typically confined to a dermatomal area of the skin following an outbreak of herpes zoster (HZ) in that same region. The neuralgia begins when the HZ vesicles have crusted over and begun to heal.
Early diagnosis of the shingles rash is important to allow prompt treatment with anti-viral agents which shorten the clinical course and to help prevent complications. However, they have no role to play if PHN has become established.
Diagnosis of post-herpetic neuralgia is with history and examination.
Treatment of PHN is with simple analgesia including codeine and NSAID's; topical therapy including lidocaine plasters and capsaicin oitment; neuropathic pain modifying therapy including amitriptyline and gabapentin, often in combination with selective serotonin reuptake inhibitors (SSRI's) and corticosteroids.
