Aim To evaluate the clinical characteristics of adult and adolescent Croatian patients hospitalized for herpes zoster over a period of 21 years in the largest national center for infectious diseases (catchment area approximately 25% of the Croatian population). Methods This retrospective chart review included all patients older than 15 years hospitalized for herpes zoster at the University Hospital for Infectious Diseases “Dr. Fran Mihaljević” between January 1, 1996 and December 31, 2016. Results The study enrolled 1755 patients (uniform annual hospitalizations), 50% of whom suffered from complicated forms of herpes zoster, mostly generalized zoster (22.0%), infected lesions (14.8%), and meningitis/encephalitis (10.4%). A low percentage of patients experienced Ramsey-Hunt syndrome (3.0%), keratitis (1.5%), and visceral dissemination (0.2%). The majority of patients were older than 55 years (80%, median 70 years). Overall, 61.6% of patients suffered from at least one comorbidity (most frequent: diabetes 14.6%, cardiovascular incidents 24.4%, malignancy 13.0%, other infection 12.9%), and 28.2% suffered from ≥2 comorbidities. All-cause in-hospital mortality was 0.9%. The proportion of patients with any complicated form and of patients with meningitis/encephalitis steadily decreased over time, while the proportion of patients with comorbidities increased. This coincided also with steadily increasing age. No association was observed between comorbidities and complicated forms of zoster. Pharmacological immunosuppression was associated with generalized zoster; younger age was associated with meningitis/encephalitis; and older age was associated with generalized zoster and infected lesions. Conclusion The patients most frequently hospitalized for herpes zoster are elderly people burdened with comorbidities, not necessarily patients with complicated forms of the disease.

BackgroundTumor necrosis factor-α (TNF-α) antagonists, most of which are monoclonal antibodies, became a widespread treatment for autoimmune diseases such as rheumatoid arthritis, ankylosing spondylitis, inflammatory bowel diseases, psoriasis, psoriatic arthritis, hidradenitis suppurativa and uveitis. Their use is based on the blockage of TNF-α, which plays an important role in granulomas formation, development of phagosomes, activation and differentiation of macrophages, immune response against viral pathogens. The multiple adverse effects of TNF-α inhibition have been identified, including a two-to four-fold increased risk of active tuberculosis and other granulomatous conditions and an increased occurrence of some other serious bacterial, fungal and certain viral infections.Case presentationA 34-year-old male patient with disseminated varicella and pneumonitis was admitted to our hospital. The diagnosis of varicella was established serologically by enzyme immunoassay (EIA) and by polymerase chain reaction confirmation of the virus in vesicular fluid. The patient has been receiving adalimumab and methotrexate for the last 3 years due to ankylosing spondylitis and was seropositive to varicella zoster virus prior to the introduction of TNF-α antagonists. Acyclovir was administered for 10 days with the resolution of clinical illness and radiological signs of pneumonitis.ConclusionDue to the use of biological agents, particularly TNF-α inhibitors, as a well-established therapy for some autoimmune diseases, new potential adverse events can be expected in the future and we wanted to point out one of them. To our knowledge this is the first case of recurrent disseminated varicella in a patient taking TNF-α antagonists.