Fig. 1.

Treatment algorithm for urticarial vasculitis (UV). ANA anti-nuclear antibodies AZA azathioprine, Blood hematotoxicity, CBC complete blood count, CMP complete metabolic panel, COL colchicine, CP cyclophosphamide, CRP c-reactive protein, CsA cyclosporine A, CSU chronic spontaneous urticaria, DAP dapson, ENA extractable nuclear antigen antibodies, ESR erythrocyte sedimentation rate, h hours, HCQ hydroxychloroquine, IgE immunoglobulin E, IL1 interleukin-1, Liver liver function, MMF mycophenolate mofetil, MTX methotrexate, NSAIDs non-steroidal anti-inflammatory drugs, nurs nursing, Oma omalizumab, Preg pregnant, Renal renal function, sgAHs second-generation anti-histamines, SGC systemic glucocorticosteroids, UVAS Urticarial Vasculitis Activity Score, UVAS7 Urticarial Vasculitis Activity Score assessed for 7 days. 1. Examples for systemic symptoms: fever, arthralgia, abdominal pain, eye inflammation. 2. Possible investigations: CBC, CRP, ESR, hepatic panel, ANA/ENA, C3, C4, CH50, C1q, creatinine, urinalysis, serum and urine protein, electrophoresis, serum immunofixation electrophoresis. If C3/C4 complement levels are below normal range class UV as HUV. 3. Neutrophilic urticarial dermatosis in autoinflammatory disease or other vasculitis. 4. Comorbidities: systemic lupus erythematosus, malignancies, active infections. 5. Consider triggers: e.g., drug withdrawal, (treatment of) underlying disease. 6. For UV diagnosis, the following should be present: leukocytoclasia, fibrin deposits, and extravasated erythrocytes [68]. 7. (Re)assess UVAS7 for past 7 days every 4 weeks and de-escalate if possible to avoid adverse events. If wheals are the only symptom present, consider treating as mild UV even if UVAS7 is higher than 7. 8. If mild disease activity with predominantly itchy wheals, treatment with sgAHs and omalizumab can be considered before taking a skin biopsy. 9. Mild UV: skin-limited symptoms with or without mild arthralgia and/or mild general symptoms. 10. When treating sgAH and omalizumab-non-responsive UV, cyclosporine may be substituted with other treatments/add-ons, e.g., low-dose SGC, HCQ or dapsone, based on the patient profile, risk-benefit assessment, and physician and patient preferences (shared decision making). 11. Unless when using paracetamol. 12. When using anakinra. 13. Based on a set schedule. 14. Do not use if neutrophils <1500/mm³. 15. Do not use if platelets <50,000/mm³