Histopathology of chronic spontaneous urticaria with occasional bruising lesions is not significantly different from urticaria with typical wheals

Abstract

Background Chronic spontaneous urticaria (CSU) may occasionally exhibit long‐lasting lesions with bruising, usually considered a hallmark of urticarial vasculitis (UV). Histopathology of these chronic urticarial lesions has not been extensively studied. Methods Skin biopsies from patients with anti‐H1 resistant CSU were evaluated for several parameters (edema, location, intensity, and cell composition of the inflammatory infiltrate, and abnormalities in the blood vessels). Results We studied 45 patients (37 female/8 male, mean age 49.3 years) with CSU, 60% of whom with occasional bruising lesions and 3 patients with hypocomplementemic UV. Histopathology in CSU showed mainly perivascular and interstitial inflammatory infiltrate (91.1%), including eosinophils (80%), neutrophils (77.8%), and lymphocytes (71.1%), vasodilatation (88.9%), intravascular neutrophils (95.6%), dermal edema (51.1%), swelling of endothelial cells (51.1%), and minor and rare fibrinoid necrosis and karyorrhexis (6.7%). Significant karyorrhexis and frank fibrinoid necrosis were observed, respectively, in two and three cases of UV. In patients with occasional bruising, mast cells occurred in fewer cases whereas eosinophils were more frequent, but no statistically significant difference was found for other parameters. Conclusions Histopathological findings were not significantly different between CSU with or without bruising lesions. Bruising may be associated with more severe forms of CSU with no histopathological signature, although UV cannot be completely excluded based on histopathology.

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 .…”

“…Cell infiltrate. In CSU, perivascular and interstitial inflammatory cellular infiltrates, resembling an allergic late-phase reaction, include eosinophils, neutrophils, lymphocytes and basophils 9,[59][60][61] . Infiltrating cells are thought to migrate from the blood into the skin in response to chemotactic factors, for example eotaxins, MCP3, RANTES, IL-5, C3a, C5a, TNF, IL-17 and plateletactivating factor (PAF), released by mast cells, activated endothelial cells, T H 2 cells, dermal fibroblasts and other cells 9 .…”

Differential diagnosis between urticarial vasculitis and chronic spontaneous urticaria: An international Delphi survey

“…Some experts saw occasional patients progress from one condition to the other (and back again). In the literature, CSU cases with occasional clinical features attributed to UV such as postinflammatory hyperpigmentation have been described, 12,14 however those cases did not show significant differences in lesional histopathology compared to CSU patients without these features 23 . In line with this, experts mostly agreed that clinical aspects of transient bruising and/or histology with minor “vascular aggression” (minor leukocytoclasia or red blood cell extravasation) may occur in CSU, particularly during severe episodes, although this is considered to be rare.…”

Differential Diagnosis of Urticarial Lesions

“…The levels of complement divide UV into normocomplementemic (NUV), hypocomplementemic (HUV) or hypocomplementemic urticarial vasculitis syndrome (HUVS) ( 19 ). About 80% of all UV patients have NUV ( 19 ) which can be difficult to distinguish, on a clinical or even histopathological level, from severe forms of CSU ( 20 , 21 ). HUV and HUVS are the most severe forms of UV and are often associated with longer disease duration and underlying disorders ( 17 ).…”