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Angioedema is a relatively rare but potentially life-threatening adverse reaction to angiotensin-converting enzyme inhibitors (ACEi) and angiotensin receptor blockers (ARBs). As with hereditary forms of angioedema (HAE), this adverse reaction is mediated by bradykinin. Research suggests that ACEi/ARB-induced angioedema has a multifactorial etiology. In addition, recent case reports suggest that some ACEi/ARBinduced angioedema patients may carry pathogenic HAE variants. The aim of the present study was to investigate the possible association between ACEi/ARB-induced angioedema and HAE genes via systematic molecular genetic screening in a large cohort of ACEi/ARB-induced angioedema cases. Targeted re-sequencing of five HAEassociated genes (SERPING1, F12, PLG, ANGPT1, and KNG1) was performed in 212 ACEi/ARB-induced angioedema patients recruited in Germany/Austria, Sweden, and Denmark, and in 352 controls from a German cohort. Among patients, none of the identified variants represented a known pathogenic variant for HAE. Moreover, no significant association with ACEi/ARB-induced angioedema was found for any of the identified common [minor allele frequency (MAF) >5%] or rare (MAF < 5%) variants. However, several non-significant trends suggestive of possible protective effects were observed. The lowest p-value for an individual variant was found in PLG (rs4252129, p.R523W, p = 0.057, p.adjust > 0.999, Fisher’s exact test). Variant p.R523W was found exclusively in controls and has previously been associated with decreased levels of plasminogen, a precursor of plasmin which is part of a pathway directly involved in bradykinin production. In addition, rare, potentially functional variants (MAF < 5%, Phredscaled combined annotation dependent depletion score >10) showed a nominally significant enrichment in controls both: 1) across all five genes; and 2) in the F12 gene alone. However, these results did not withstand correction for multiple testing. In conclusion, our results suggest that HAE-associated mutations are, at best, a rare cause of ACEi/ARB-induced angioedema. Furthermore, we were unable to identify a significant association between ACEi/ARB-induced angioedema and other variants in the investigated genes. Further studies with larger sample sizes are warranted to draw more definite conclusions concerning variants with limited effect sizes, including protective variants. [ABSTRACT FROM AUTHOR]

Background: The pathophysiology of the underlying paroxysmal permeability disturbances in angioedema (AE) is not well understood. Methods: To identify clinical and laboratory parameters specific for a certain AE subtype, 40 AE patients were prospectively enrolled: 15 hereditary (HAE), 13 ACE‐inhibitor induced (ACE‐AE), and 12 mast cell‐mediated without wheals in chronic spontaneous urticaria (CSU‐AE). Ten healthy subjects served as controls. Serum levels of markers indicating activation of the ficolin‐lectin pathway, of endothelial cells, or those indicating impairment of vascular integrity or inflammation were assessed by enzyme‐linked immunosorbent assay. Results: New routine clinical diagnostic criteria could not be identified, not even for distinguishing bradykinin‐mediated (BK‐) AE (ie, HAE and ACE‐AE) from mast cell‐/histamine‐mediated CSU‐AE. However, FAP‐α and tPA were significantly increased in all AE compared to controls. In HAE, FAP‐ α, tPA, uPAR, pentraxin‐3, Tie‐2, sE‐selectin, and VE‐cadherin were significantly increased compared to controls. In HAE compared to CSU‐AE and ACE‐AE, sE‐Selectin, Tie‐2, and VE‐Cadherin were significantly increased, whereas for Ang‐2 the difference was significant compared to CSU‐AE only. Tie‐2 correlated strongly negatively with C4, C1‐INH activity, and C1‐INH function. Conclusions: This study is the first to compare HAE, ACE‐AE, and CSU‐AE. Although significance is limited by small sample size, Tie‐2 was identified as a new promising biomarker candidate for HAE. FAP‐ α and tPA might serve as a marker for AE in general, whereas sE‐selectin and Ang‐2 were increased in BK‐AE only. Our results add information to the role of endothelial dysfunction and serine proteases in different AE subtypes. [ABSTRACT FROM AUTHOR]

Abstract Urticaria is a group of diseases that share a distinct skin reaction pattern. Triggering of urticaria by infections has been discussed for many years but the exact role and pathogenesis of mast cell activation by infectious processes is unclear. In spontaneous acute urticaria there is no doubt for a causal relationship to infections and all chronic urticaria must have started as acute. Whereas in physical or distinct urticaria subtypes the evidence for infections is sparse, remission of annoying spontaneous chronic urticaria has been reported after successful treatment of persistent infections. Current summarizing available studies that evaluated the course of the chronic urticaria after proven Helicobacter eradication demonstrate a statistically significant benefit compared to untreated patients or Helicobacter-negative controls without urticaria (p < 0.001). Since infections can be easily treated some diagnostic procedures should be included in the routine work-up, especially the search for Helicobacter pylori. This review will update the reader regarding the role of infections in different urticaria subtypes.

International guidelines for the treatment of chronic spontaneous urticaria support the updosing of second-generation antihistamines to four times of the approved dose when adequate symptom control cannot be achieved with the standard dosage. However, this recommendation is primarily based on expert opinions, and there is a lack of large, well-designed, double-blind clinical trials. Most the existing trials provide insufficient data, and due to the heterogeneity of the conducted trials on antihistamine effects (definition of control, design, quality, lack of an active comparator, no placebo arm, small sample size, outcomes) and their short duration, comparative analysis is challenging. However, it can be concluded that the use of modern second-generation antihistamines is both effective and safe based on the available data and our own long-term experiences in the specialized outpatient clinic of a university dermatology department, even though increased dosages (up to fourfold as per the current international guidelines) may be necessary for symptom control. Another therapeutic option for refractory symptoms in chronic spontaneous urticaria is subcutaneous administration of omalizumab at a dosage of 300 mg at 4‑week intervals as a very safe and effective treatment., (© 2024. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)