A novel histopathological scoring system to distinguish urticarial vasculitis from chronic spontaneous urticaria

Abstract

Background: Urticarial vasculitis (UV) is defined by long-lasting urticarial lesions combined with the histopathologic findings of leukocytoclastic vasculitis. As one of the major unmet needs in UV, diagnostic criteria are rather vague and not standardized. Moreover, there seems to be considerable overlap with chronic spontaneous urticaria (CSU), particularly for the normocomplementemic variant of UV.Therefore, this study aimed to develop a diagnostic scoring system that improves the histopathologic discrimination between UV and CSU.Methods: Lesional skin sections of patients with clinical and histopathologic diagnosis of UV (n = 46) and CSU (n = 51) were analyzed (blinded to the diagnosis) for the following pre-defined criteria: presence of leukocytoclasia, erythrocyte extravasation, fibrin deposits, endothelial cell swelling, ectatic vessels, blurred vessel borders, dermal edema, intravascular neutrophil, and eosinophil numbers and numbers of dermal neutrophils, macrophages and mast cells.Results: The greatest differences between UV and CSU samples were observed for leukocytoclasia (present in 76% of UV vs. 3.9% of CSU samples; p < 0.0001), erythrocyte extravasation (present in 41.3% of UV vs. 2.0% of CSU samples; p < 0.0001), and fibrin deposits (present in 27.9% of UV vessels vs. 9.7% of CSU vessels; p < 0.0001). Based on these findings, we developed a diagnostic score, the urticarial vasculitis score (UVS), which correctly assigned 37 of 46 cases of UV and 49 of 51 cases of CSU to the previously established diagnosis. Conclusion:Our results suggest that the UVS, a combined quantitative assessment of the three criteria leukocytoclasia, fibrin deposits and extravasated erythrocytes, distinguishes UV from CSU in skin histopathology. The UVS, if validated in larger patient samples, may help to improve the diagnostic approach to UV.

Urticaria

“…In urticarial vasculitis, both long-lasting wheals (>24 h) and angioedema can occur and the diagnosis is confirmed by a combination of three histological criteria: leukocytoclasia, fibrin deposits and extravasated erythrocytes 132,133 . By contrast, CSU histopathology usually shows dermal oedema with an inflammatory infiltrate consisting of lymphocytes, eosinophils, neutrophils and nuclear dust, without evidence of vasculitis 60,132 .…”

Chronic recurrent wheals – If not chronic spontaneous urticaria, what else?

“…Based on complement consumption, normocomplementemic urticarial vasculitis (~ 80% of patients) differs from hypocomplementemic urticarial vasculitis (~ 9 – 21% of patients), which is often associated with increased clinical symptoms, or the even rarer hypocomplementemic urticarial vasculitis syndrome [ 4 ]. The histologic picture of urticarial vasculitis is characterized by erythrocyte extravasations and fibrin deposits in addition to leukocytoclastic vasculitis and can thus be distinguished from the histologic picture of chronic spontaneous urticaria [ 11 ]. The management of patients with urticarial vasculitis is a challenge worldwide due in part to the lack of guidelines and treatment algorithms [ 12 ].…”

Urticaria: A Narrative Overview of Differential Diagnosis

“…A recent study shed light on a novel dermoscopic sign that can significantly aid in the diagnosis of UV: subclinical purpuric patches/globules (PG) can be seen in UV lesions with dermoscopy (19-fold increase in the odds for UV at multivariate analysis) [ 45 ].…”

“…The main histological criteria include: signs of karyorrhexis (nuclear dust), presence of erythrocytes outside the vessels, presence of fibrin inside the vessels and neutrophilic infiltrate. An urticarial vasculitis score (UVS), which is a combined quantitative assessment of the three criteria leukocytoclasia, fibrin deposits and extravasated erythrocytes, showed promising results in distinguishing UV from CSU in skin histopathology [ 45 ].…”