A recent Delphi survey facilitated the establishment of diagnostic criteria and differential diagnoses between urticarial vasculitis and chronic spontaneous urticaria patients presenting with recurring wheals.
Urticarial vasculitis (UV) is characterized by long-lasting wheals with or without angioedema and the histopathologic finding of leukocytoclastic vasculitis. Distinguishing UV from chronic spontaneous urticaria (CSU) can be challenging due to similar clinical features, leading to a delayed or incorrect diagnosis.
This survey study aimed to address diagnostic uncertainties and unmet needs in the diagnosis of UV, including the differential diagnosis with CSU and the potential coexistence of both conditions. The study’s results were published in the journal Clinical and Translational Allergy.
Expert Consensus on Diagnostic Criteria for UV and CSU
Thirteen specialists participated in a Delphi survey conducted by the European Academy of Allergy and Clinical Immunology taskforce. This survey consisted of three rounds of anonymous responses to 32 questions, with the goal of consolidating the experts’ opinions and reaching a consensus.
The experts overwhelmingly pointed out the lack of clear diagnostic criteria distinguishing between CSU and UV as an unmet need. While there was general agreement on the definition of UV as wheals persisting for more than 24 hours with histopathological evidence, doubts were raised about the presence of classic signs of leukocytoclastic vasculitis in all UV patients.
Differentiating Between CSU and Non-Urticarial Vasculitis
Based on the agreed statements, 85% of core experts and 86% of urticaria specialists find evidence of an unmet need to distinguish between CSU and non-urticarial vasculitis (NUV). The majority of urticaria specialists consider hypocomplementemic UV to be a separate condition that does not overlap with CSU; however, there is no consensus regarding this distinction.
Nearly all core experts and urticaria specialists agree that the main diagnostic challenge lies in determining whether CSU and NUV are truly distinct entities or if they represent different presentations of the same disease spectrum characterized by wheals. Finally, almost all core experts and urticaria specialists (100% and 99%, respectively) conclude that further studies are needed to better understand the differences and similarities between CSU and UV patients.
Coexistence of CSU and NUV With Varied Perspectives
The expert group agreed that CSU and NUV can coexist. Thus, CSU patients may occasionally show signs and symptoms of UV, for example, lesions lasting 24 h or more that progress to transient purpura or bruising before resolution. Although many core experts agreed that CSU and NUV are part of a disease continuum rather than two different entities, only half of the urticaria specialists approved this consensus.
Recommendations for Lesional Skin Biopsy and Diagnostic Criteria
Experts agree that if wheals last for more than 24 hours, show signs of resolution with bruising, or if systemic symptoms are present, patients with recurrent wheals should undergo a lesional skin biopsy. Histologic criteria for diagnosing UV include leukocytoclasia and fibrin deposits in vessel walls. Additional laboratory tests, such as anti-nuclear antibody (ANA) titers and C-reactive protein (CRP) levels, can also help with the diagnosis.
Systemic Symptoms as Diagnostic Clues for Urticarial Vasculitis
Twelve experts have identified systemic symptoms as an important clue for diagnosing UV. The most commonly reported symptoms were fever (100%), arthralgia or arthritis (92%), and malaise or fatigue (50%).
Biopsy Strategies in CSU Patients Suspected of NUV
However, there was no consensus among the experts regarding which lesions should be biopsied in a patient initially diagnosed with CSU but suspected to have NUV. Some experts preferred to biopsy a new (early) lesion (39%), the non-bruising area of a progressing lesion (54%), or a late lesion already in the bruising area (54%). Furthermore, some experts suggested that a second biopsy may be necessary in certain cases to confirm or clarify unclear results from the initial biopsy.
Source:
Krause, K., Bonnekoh, H., Jelden‐Thurm, J., Asero, R., Arnau, A. G., Cardoso, J. C., Grattan, C., Kocatürk, E., Lippert, U., Maurer, M., Metz, M., Staubach, P., Gonçalo, M., & Kolkhir, P. (2023). Differential diagnosis between urticarial vasculitis and chronic spontaneous urticaria: An international Delphi survey. Clinical and Translational Allergy, 13(10). https://doi.org/10.1002/clt2.12305
