Factors influencing pain outcome in herpes zoster: an observational study with valaciclovir

Aim of the study An observational study with valaciclovir was conducted to assess clinical outcome in herpes tester, especially pain and associated ne urological signs and symptoms in relation to a series of demographic and di sease characteristics discernible at presentation. The safety and acceptabi lity of valaciclovir for treatment of tester was assessed in a wide variety of primary care and clinic referral settings. Methods In total, 1897 immunocompetent adults with clinically diagnosed, lo calized acute herpes tester were enrolled in this international, open-label study of valaciclovir. AU subjects received treatment with oral valaciclov ir (1000 mg three times daily) for 7 days from entry to the study and were asked to record the presence of tester-associated pain and abnormal sensati ons throughout treatment and 6 months follow-up. They were seen frequently in clinic to verify subjective assessments and for evaluation of rash heali ng. Safety and tolerability were assessed by adverse event monitoring. Results Overall, 1191 subjects (63%) were aged greater than or equal to 50 years, and 203 (11%) had ophthalmic tester. Cessation of tester-associated pain was significantly faster in the younger age group; median times to los s of tester-associated pain were 23 days and 9 days in the greater than or equal to 50 and < 50 years age groups, respectively. Similarly, abnormal se nsations resolved significantly more rapidly in the younger subjects; the m edian duration of abnormal sensations was 31 days in the greater than or eq ual to 50 year olds and 16 days in those aged < 50 years. In cases of ophth almic tester, the rate of pain resolution was not different from those with tester in other dermatomes (median duration of pain 18 vs. 16 days). Howev er, abnormal sensations persisted significantly longer in subjects with oph thalmic tester than in those with tester at other sites (47 vs. 22 days). I n addition to advancing age, subjects suffering moderate to severe prodroma l pain or acute pain during the rash phase were at significantly greater ri sk of zoster-associated pain and abnormal sensations persisting for longer. Subjects with concomitant neurological disorders were also more likely to develop prolonged abnormal sensations. Valaciclovir treatment was well tole rated, and adverse events were rare and generally mild. Conclusion This study confirmed the prognostic importance of advancing age and the intensity of prodromal or acute pain as risk factors for prolonged tester-associated pain and persisting abnormal sensations in the affected d ermatome. Ophthalmic tester and pre-existing neurological disorders are als o identified as highly significant risk factors for prolonged abnormal sens ations in herpes tester.