Efficacy of Extracorporeal Shockwave Therapy for Postherpetic Neuralgia

Traditional therapies for postherpetic neuralgia (PHN) and postherpetic itch (PHI) often yield unsatisfactory outcomes. Previous investigations on extracorporeal shockwave therapy (ESWT) have demonstrated positive outcomes in pain and itch reduction in conditions resembling PHI and PHN, exhibiting neuropathic mechanisms. This study aims to evaluate the impact of ESWT on pain and itch associated with PHN and PHI.

Inclusion criteria encompassed individuals aged 50 to 80 displaying symptoms indicative of PHN or PHP (persistent pain duration exceeding 3 months), undergoing conventional conservative therapies like combination medication and nerve blocks, with reported pain or pruritus scores surpassing 3 on a numerical rating scale (NRS) (treatment group, n = 10; sham stimulation group, n = 9). The experimental group received 2000 shock waves per treatment, with each shock wave comprising 100 impulses/cm², characterized by low-energy flux density (0.07-0.20 mJ/mm²), administered with a 1-week interval between treatments over 6 weeks.

After two sessions of ESWT, pain scores significantly decreased (p = 0.04), with continued reduction through six sessions (p < 0.001) and at 1-month follow-up (p < 0.001). Pruritus scores also improved from session two (p = 0.03) and remained significant (p < 0.001, p = 0.001). Between-group differences became apparent after four sessions for pruritus (p = 0.06) and after six sessions for the 5-D Itch scale (p = 0.007). Pregabalin dosage was significantly reduced in the ESWT group (p = 0.04). No adverse effects were reported.

ESWT, as a noninvasive therapeutic approach, significantly alleviated PHN-associated pain and pruritus.