Risk of herpes zoster in psoriatic patients undergoing biologic treatment

The advent of biologic treatments for psoriasis has many benefits, such as considerably improved efficacy and lower frequency of organ toxicity. While the frequency of organ dysfunction during biologic treatment is considered to be low, the incidence of infection is slightly higher. Patients on biologic treatments are regularly monitored to be able to detect the onset of infection, because there is evidence of an increase in the risk of bacterial and fungal infections during treatment. A total of 144 patients who had received biologic treatment for a year were retrospectively examined. We encountered four cases, including one of 39 patients on infliximab treatment, two of 65 patients on adalimumab treatment and one of 40 patients on ustekinumab treatment, who developed herpes zoster (HZ) within 1 year of starting biologic treatment. Our experience shows that this incidence could be higher than that in the general population, although the data is retrospective. On consideration of previous studies and our own experiences, the risk of HZ occurrence during biologic treatments for psoriasis may increase.