This is a single-center open label study to assess the efficacy and safety of single doses of canakinumab (trade name Ilaris®), a high-affinity monoclonal antibody that neutralizes IL-1β, in patients with active urticarial vasculitis. Efficacy is primarily assessed by a combined symptom score, the urticarial vasculitis activity score (UVAS). Following a baseline period of 2 weeks, patients will be dosed with two single s.c. injections of 150 mg (consistent with a total dose of 300 mg canakinumab). Visits for investigator's assessments will be scheduled at 1 week, 2 weeks, 4 weeks, 8 weeks, 12 weeks and 16 weeks post dose. Patient's self-assessment will be performed on a daily basis throughout the study. Overall a max. of 10 subjects with urticarial vasculitis will be enrolled.