Background: Herpes zoster (HZ) is associated with inflammation of the peripheral nerves, which is considered to be an important cause of postherpetic neuralgia (PHN). Interventions aimed at reducing this inflammation could prevent PHN. One option is the epidural administration of corticosteroid and local anesthetic. However, several authors have reported a risk of arachnoiditis with epidural corticosteroids. Subcutaneous injection in an outpatient setting is a safer option. However, there is limited evidence of the effectiveness of this alternative for preventing PHN.
Objectives: The aim of this study was to assess the effectiveness of subcutaneous injection of triamcinolone and lidocaine for the prevention of PHN in elderly HZ patients.
Study design: Randomized, single-center, clinical trial.
Setting: Department of pain management of a teaching hospital in Beijing, China.
Methods: Patients with acute HZ with rash < 7 days (n = 100) were randomly assigned to receive either standard therapy (oral antivirals and analgesics) alone or standard therapy plus subcutaneous injection of triamcinolone and lidocaine. The severity of pain was assessed using a numeric rating scale (NRS) at enrollment and at one, 3, and 6 months after rash onset. Quality of life (QoL) was evaluated by the SF-36 before treatment and at 3 and 6 months after rash onset. The primary endpoint was the presence of zoster-associated pain (ZAP) at 3 months after rash onset.
Results: At enrollment, all patients reported ZAP with average NRS scores of 6.64 ± 1.44 and 7.16 ± 1.22 in the standard group and subcutaneous group, respectively. At 3 and 6 months after rash onset, the pain had decreased in both groups, but the decrease was significantly greater in the subcutaneous injection group. At 3 months, 2 (4%) patients in the subcutaneous injection group vs. 10 (20%) patients in the standard group had ZAP with NRS > 3 (P = 0.014). Both groups showed significant improvement in QoL at 3 and 6 months. No patient had major adverse events related to the subcutaneous injection.
Limitations: The main limitation of the study was the absence of a placebo subcutaneous injection in the standard group.
Conclusion: Subcutaneous injection of triamcinolone and lidocaine in the acute phase of HZ can reduce ZAP more effectively than oral antivirals and analgesics alone, and may be a feasible method to prevent PHN.
Key words: Subcutaneous injection, lidocaine, triamcinolone, postherpetic neuralgia, prevention.