Clinical epidemiology and risk factors of herpes zoster in Türkiye: a decade-long, multicenter retrospective cohort study

Herpes zoster (HZ) results from the reactivation of varicella-zoster virus (VZV) in dorsal root ganglia, often triggered by immune decline. This multicenter study aimed to describe the frequency, clinical and demographic characteristics, and risk factors of HZ in Türkiye to inform clinical management and prevention strategies. This retrospective analysis was conducted on 503 patients diagnosed with HZ between 2014 and 2024 across 17 hospitals in nine Turkish provinces. Data included demographics, comorbidities, immunosuppressive therapy, dermatomal involvement, rash duration, antiviral treatment, and vaccination status. Descriptive statistics were applied. A total of 503 patients were included in the study. Of these, 281 (55.9%) were female including 10 pregnant women (3.5%) and 222 (44.1%) were male, with a mean age of 59 ± 16 years (range: 20–101). Sixty-one patients (12.1%) were using immunosuppressive drugs during the zoster episode, and 324 (64.4%) had comorbid diseases. Strikingly, only one patient (0.2%) had received the zoster vaccine, highlighting a critical gap in preventive medicine. While 246 (48.9%) patients had a history of chickenpox during childhood, 11 (2.2%) had experienced more than one episode of zoster previously. Forty-three (8.6%) patients had multiple dermatome involvement, while 459 (91.4%) had single dermatome involvement. The distribution of dermatome involvement in order of frequency was as follows: thoracic (n = 256, 50.9%), lumbar (n = 110, 21.9%), sacral (n = 51, 10.1%), trigeminal (n = 100, 19.9%), cervical (n = 16, 3.2%), and periorbital (n = 16, 3.2%). The mean duration of rash was 15.1 days for all patients, while this duration was 15.3 days in those with comorbidities, 18.6 days in patients using immunosuppressive drugs, and 17.2 days in pregnant women. The antivirals used in treatment were valacyclovir (n = 310, 61.6%), acyclovir (n = 145, 28.8%), and brivudine (n = 18, 3.6%). The duration of rash was 14.6 days in those treated with valacyclovir, 16.1 days in those treated with brivudine, and 17.0 days in those treated with acyclovir. HZ is a disease whose frequency increases particularly with advancing age, and careful management is required especially in patients with comorbidities, pregnant women, and those receiving immunosuppressive therapy. Identifying and informing individuals in risk groups, raising their awareness. The near-total absence of vaccination in our cohort underscores the urgent need for national health policies to improve vaccine accessibility.