Urticarial Vasculitis Differs From Chronic Spontaneous Urticaria in Time to Diagnosis, Clinical Presentation, and Need for Anti-Inflammatory Treatment: An International Prospective UCARE Study

Background: Chronic spontaneous urticaria (CSU) and urticarial vasculitis (UV) share several clinical features including the occurrence of wheals. As of yet, the criteria for differentiating the 2 disorders are not clearly defined. Objective: Here, we aimed to identify differences, similarities, and the likelihood for specific clinical features in patients with UV versus those with CSU. Methods: Across 10 Urticaria Centers of Reference and Excellence, 106 patients with skin biopsy–confirmed UV and 126 patients with CSU were prospectively recruited to complete a questionnaire on the clinical features, course, and response to treatment of their disease. Results: As compared with CSU, patients with UV more often experienced postinflammatory skin hyperpigmentation, wheals of ≥24-hour duration, eye inflammation, and fever (6.9, 4.0, 3.6, and 2.4 times, respectively). Clinical features that increased the risk for UV diagnosis when present at the onset of disease included wheals of ≥24-hour duration (7.3-fold), pain of the skin (7.0-fold), postinflammatory hyperpigmentation (4.1-fold), and fatigue (3.1-fold). The diagnostic delay was markedly longer for normocomplementemic UV as compared with hypocomplementemic UV and CSU (21 vs 5 vs 6 months, respectively). Oral corticosteroids and omalizumab were the most effective treatments in patients with UV and CSU, respectively. Patients with UV showed a higher need for immunosuppressive and anti-inflammatory therapies than patients with CSU. Conclusions: Long wheal duration, skin pain and hyperpigmentation, and systemic symptoms point to UV rather than CSU as the underlying disease and should prompt further diagnostic workup including a skin biopsy.