Possible association of lower rate of postherpetic neuralgia in patients on anti-tumor necrosis factor-α.

Recently, a study of patients with rheumatoid arthritis who developed herpes zoster while taking a tumor necrosis factor (TNF)-α inhibitor reported a decreased incidence of postherpetic neuralgia. The objective of this study was to investigate whether patients on TNF-α inhibitors who developed herpes zoster have a lower incidence of subsequent development of postherpetic neuralgia. A retrospective review of herpes zoster patients on TNF-α inhibitors (infliximab, etanercept, or adalimumab) was conducted in 12 dermatology clinics. Medical records of such patients were reviewed thoroughly to confirm herpes zoster and TNF-α inhibitors and any subsequent development of postherpetic neuralgia (pain score ≥ 3 out of 10 after 90 days of shingles onset) was noted. A total of 206 cases were reviewed, of which only 2 cases (<1%) developed postherpetic neuralgia, a considerably lower incidence rate than noted in the literature. Increasing age is a known risk factor in the development of postherpetic neuralgia. However, of the 58 (28.1%) cases ≥ 70 years of age, only 1 patient (1.7%) developed neuralgia compared to approximately 50% of patients who develop postherpetic neuralgia in this age group as reported in the literature. Treatment with TNF-α inhibitors may be associated with a lower incidence of postherpetic neuralgia but further prospective large-scale studies are needed to confirm this data.