Abstract
BACKGROUND: The incidence of postherpetic neuralgia (PHN) is highly variable due to the lack of a uniform definition of PHN and differing views on its severity. Most of the studies on risk factors for PHN are retrospective, and pain severity has not been uniformly graded. There is also a paucity of literature on cytokine levels as markers for the development of PHN. A few studies done so far have shown conflicting results. The objective of this study was to assess the association of clinical factors, interleukin 4 (IL4), and IL17 levels during acute zoster with the development of PHN, as well as to grade PHN using the Zoster Brief Pain Inventory (ZBPI). PATIENTS AND METHODS: Eighty clinically diagnosed herpes zoster cases within 1 week of the onset of the rash were recruited. The severity of prodromal pain and acute zoster pain was analyzed based on the visual analog scale and ZBPI, respectively. IL4 and IL17 estimation was done using enzyme-linked immunosorbent assay kits. Patients were followed up in the first and third months for the presence of PHN using ZBPI. RESULTS: PHN was present in 54 (67.5%) cases during the first month and 38 (47.5%) during the third month. Age (40-60 years; P = 0.03), trigeminal distribution (P = 0.05), lesion number between 25 and 50 (P = 0.008), presence of prodromal pain (P = 0.01), zoster-associated pain (P = 0.04), higher IL4 (P = 0.02) and IL17 (P = 0.01) levels had a significant association with PHN in the third month. Using logistic regression, PHN risk increased with increasing age. Moderate to severe PHN was present in 8 (10%) patients in the third month. No significant difference in clinical characteristics and cytokine levels was found between patients with mild and moderate to severe PHN. LIMITATIONS: Relatively small sample size. CONCLUSION: IL4 and IL17 may be potential markers for the risk of PHN, and the role of these markers needs to be studied further.