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 two disorders are not clearly defined.

OBJECTIVE: Here, we aimed to identify differences, similarities and the likelihood for specific clinical features in UV versus CSU patients.

METHODS: Across 10 Urticaria Centers of Reference and Excellence (UCAREs), 106 patients with skin biopsy-confirmed UV and 126 CSU patients were prospectively recruited to complete a questionnaire on the clinical features, course, and response to treatment of their disease.

RESULTS: As compared to CSU, UV patients more often experienced post-inflammatory skin hyperpigmentation, wheals of ≥24h 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 ≥24h duration (7.3-fold), pain of the skin (7.0-fold), post-inflammatory hyperpigmentation (4.1-fold), and fatigue (3.1-fold). The diagnostic delay was markedly longer for normocomplementemic UV as compared to hypocomplementemic UV and CSU (21 vs 5 vs 6 months, respectively). Oral corticosteroids and omalizumab were the most effective treatments in UV and CSU patients, respectively. UV patients showed a higher need for immunosuppressive and anti-inflammatory therapies than CSU patients.

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 work-up including a skin biopsy.