Response to ‘IgA vasculitis in adults: few certainties and many uncertainties’ by Hočevar et al

We thank Hocevar and colleagues for their comments on our recently published work on the epidemiology of IgA vasculitis (IgAV) in adults and children.1 2 We agree that there is some uncertainty regarding the incidence of adult-onset IgAV as this has not previously been widely studied. Our calculated incidence of 2.20 (95% CI 2.08 to 2.37) per 100 000 person-years in adults is slightly higher than most previous work has suggested, but is lower than that reported by Hocevar et al in a Slovenian tertiary centre study with no clearly demarcated denominator population.2–4 This disparity may be related to interpopulation differences, for example, in exposure to environmental risk factors such as viral infections.5 Alternatively, the difference may be due to contrasting strategies used to identify cases of IgAV. Hocevar and colleagues used both clinical and …