Herpesvirus-associated acute urticaria: an age matched case-control study

How Infection and Vaccination Are Linked to Acute and Chronic Urticaria: A Special Focus on COVID-19

Since more than a century ago, there has been awareness of the connection between viral infections and the onset and exacerbation of urticaria. Our knowledge about the role of viral infection and vaccination in acute and chronic urticaria improved as a result of the COVID-19 pandemic but it has also highlighted knowledge gaps. Viral infections, especially respiratory tract infections like COVID-19, can trigger the onset of acute urticaria (AU) and the exacerbation of chronic urticaria (CU). Less frequently, vaccination against viruses including SARS-CoV-2 can also lead to new onset urticaria as well as worsening of CU in minority. Here, with a particular focus on COVID-19, we review what is known about the role of viral infections and vaccinations as triggers and causes of acute and chronic urticaria. We also discuss possible mechanistic pathways and outline the unmet needs in our knowledge. Although the underlying mechanisms are not clearly understood, it is believed that viral signals, medications, and stress can activate skin mast cells (MCs). Further studies are needed to fully understand the relevance of viral infections and vaccinations in acute and chronic urticaria and to better clarify causal pathways.

Association between serological indicators of past contacts with Herpesviridae and a slower resolution of chronic spontaneous urticaria in children

AIM

To evaluate the relationship between serological indicators of Herpesviridae infection and evolution of symptoms in children with chronic spontaneous urticaria (CSU).

METHODS

In this observational study, consecutive children with CSU underwent, at presentation, clinical and laboratory work-up, autologous serum skin test (ASST) to identify autoimmune urticaria (CAU), disease severity assessment (urticaria activity score 7, UAS7), serological diagnostics for Epstein-Barr virus (EBV), cytomegalovirus (CMV), human herpes virus-6 (HHV-6), and parvovirus B19, as well as for Mycoplasma pneumoniae and Chlamydia pneumoniae. Children were re-assessed at 1, 6, and 12 months after the commencement of antihistamine/antileukotriene treatment.

RESULTS

None of the 56 included children had an acute CMV/EBV or HHV-6 infection, but 17 (30.3%) had IgG antibodies against CMV, EBV, or HHV-6 (five were also seropositive for parvovirus B19); 24 (42.8%) suffered from CAU; and 9 (16.1%) were seropositive for Mycoplasma/Chlamydia pneumoniae. The initial symptom severity was moderate-to-severe (UAS7 quartiles 18-32) and comparable between Herpesviridae-seropositive and Herpesviridae-seronegative patients. At 1, 6, and 12 months, UAS7 was consistently higher in seropositive children. In a multivariable analysis (adjusted for age, baseline UAS7, ASST, mean platelet volume, and other serology), Herpesviridae seropositivity was associated with higher UAS scores: mean difference 4.2 score points (95% confidence interval 0.5-7.9; Bayes estimate 4.2, 95% credible interval 1.2-7.3) in a mixed model for repeated measures. This estimate was comparable between children with positive (CAU) and negative (CSU) ASST.

CONCLUSION

A history of CMV/EBV/HHV-6 infection might contribute to a slower-resolving CSU in children.

Toll-Like Receptor 7 (TLR7) Mediated Transcriptomic Changes on Human Mast Cells

Background

Mast cells are skin immune sentinels located in the upper dermis, where wheal formation and sensory nerve stimulation take place. Skin inflammation is occasionally accompanied by mast cell-driven responses with wheals, angioedema, or both. Immunoglobulin E (IgE) antibodies are regarded as typical stimuli to drive mast cell activation. However, various causative factors, including microbial infections, can drive IgE-independent mast cell response. When infected, the innate immunity orchestrates an immune response by activating receptor signaling via Toll-like receptors (TLRs).

Objective

In this study, we determined the effect of TLR7 stimulation on mast cells to investigate the possible mechanism of IgE-independent inflammatory response.

Methods

Human mast cell (HMC) line, HMC-1 cells were treated with TLR7 agonist and the morphologic alteration was observed in transmission electron microscopy. Further, TLR7 agonist treated HMC-1 cells were conducted to RNA sequencing to compare transcriptomic features.

Results

HMC-1 cells treated with TLR7 agonist reveals increase of intracellular vesicles, lipid droplets, and ribosomes. Also, genes involved in pro-inflammatory responses such as angiogenesis are highly expressed, and Il12rb2 was the most highly upregulated gene.

Conclusion

Our data suggest that TLR7 signaling on mast cells might be a potential therapeutic target for mast cell-driven, IgE-independent skin inflammation.

Predictive factors for progression to chronicity or recurrence after the first attack of acute urticaria in preschool-age children

INTRODUCTION AND OBJECTIVES

Preschool-aged group is frequently affected by urticaria, and infections are the most frequently documented factors that cause acute urticaria in children. This prospective study was designed to investigate the underlying factors of acute urticaria in under five-year-old children and to describe predictive factors for progression to chronicity or recurrence after the first attack.

PATIENTS AND METHODS

Children younger than five years of age with acute urticaria were recruited between July 2015 and July 2016. Patients (n=83) were grouped into those below and above two years of age. In order to assess the risk factors for progression to chronicity or recurrence, logistic regression analysis was performed.

RESULTS

Upper respiratory tract infection was the most common detectable reason for acute urticaria (49.4%). Herpes Simplex Virus type 1 was significantly isolated in the cases with the manifestation of an acute single-episode urticaria (p=0.042). Angioedema and food allergy were predominantly observed under two years old (p=0.001, p=0.006 respectively). A positive relationship was determined between the duration of urticaria and chronicity (r=0.301, p=0.006). The absence of atopic dermatitis (OR: 6.95, 95% CI: 1.35-35.67, p=0.020), negative Herpes virus serology (OR: 4.25, 95% CI: 0.83-21.56, p=0.040), and unknown etiology (OR: 3.30, 95% CI: 1.12-9.71, p=0.030) were the independent risk factors for recurrent urticaria.

CONCLUSIONS

Preschool-aged children with acute urticaria should be evaluated for infections at the time of admission. Patients with unknown etiology, negative Herpes virus serology, absence of atopic dermatitis, and long lasting urticaria should be followed up for chronicity and recurrence.

Urticaria in children and adolescents: An updated review of the pathogenesis and management

The present survey represents the latest data on diagnosis and management of childhood urticaria. It has been observed that urticaria occurs less often in children than adults, with symptoms rarely lasting for over 6 weeks. Triggers or aggravating factors can be found only in 21%-55% of cases. Finding autoantibodies in children does not impact a disease prognosis, unlike in adult patients, where the presence of autoantibodies is associated with a more prolonged run of the disease, a more severe prognosis and more intensive treatment methods. The incidence of food allergy equals to 8%-10% of cases. The incidence of Helicobacter Pylori infection in children is lower than that in adults and comes to 10%-18%. Medical experts recommend using the same treatment schemes for adults and children. This survey describes different urticaria management patterns suggested by experts from Europe, America, and Russia in their recent guidelines. It has been noted that unlike the guidelines from 2014, the 2018 clinical practice guidelines for the diagnosis and management of urticarial once again suggest a four-step treatment scheme with assigning omalizumab for Step 3 and cyclosporine A for Step 4 in the event of low therapeutic efficacy of the previous step or its impossibility. Leukotriene antagonists (LTRAs) are currently removed from basic management to alternative programs.

Serological evidence that activation of ubiquitous human herpesvirus-6 (HHV-6) plays a role in chronic idiopathic/spontaneous urticaria (CIU)

Acute infection with viral pathogens in the herpesviridae family can trigger acute urticaria, and reactivation of herpesviridae is associated with cutaneous urticarial-like syndromes such as drug-induced hypersensitivity syndrome/drug reaction with eosinophilia and systemic symptoms (DRESS). Reactivation of latent herpesviridae has not been studied systematically in chronic idiopathic/spontaneous urticaria (CIU). This review proposes that CIU is an inflammatory disorder with autoimmune features (termed 'CVU' for chronic viral urticaria), based on serology consistent with the hypothesis that reactivation of a latent herpesvirus or -viruses may play a role in CIU. Serology obtained from a cohort of omalizumab (Xolair)-dependent patients with severe CIU was consistent with previous HHV-6 infection, persistent viral gene expression and replication. CIU patients also exhibited serological evidence of increased immune response to HHV-4 (Epstein-Barr virus, or EBV) but not all CIU patients were infected with EBV. These observations, combined with case reports of CIU response to anti-viral therapy, suggest that HHV-6, possibly interacting with HHV-4 in cutaneous tissues, is a candidate for further prospective study as a co-factor in CIU.

Epstein-Barr virus: dermatologic associations and implications: part I. Mucocutaneous manifestations of Epstein-Barr virus and nonmalignant disorders

Epstein-Barr virus (EBV) is a ubiquitous virus that has been implicated in a wide range of human diseases, many of which have mucocutaneous manifestations. As a member of the herpesviridae family, EBV causes lifelong infection by establishing latency in B lymphocytes. An intact immune response is critical in preventing progression of EBV disease, and the clinical manifestations of infection are dependent on the intricate relationship between virus and host immune system. This review provides a comprehensive overview of the epidemiology, pathophysiology, and diagnostic testing in EBV infection. In part I of this continuing medical education article, the mucocutaneous manifestations of EBV infection are reviewed with an emphasis on pathophysiology and management.