Chronic urticaria following acute hepatitis A

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.

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.

Clinical and laboratory assessment for the inflammation role in chronic spontaneous urticaria: A clinical study

Chronic spontaneous urticaria (CSU) is triggered by unknown causes. We would like to explore the possible effect of hemogram parameters and several biochemical markers on CSU presence and also the severity of the disease. We also aimed to discuss the relationship between CSU and inflammation associated with these values. The study was planned prospectively. We selected patients already diagnosed with CSU who applied to the dermatology outpatient clinic and healthy controls. The patients and the healthy controls were tested for complete blood count, neutrophil/lymphocytes ratio and platelets/lymphocytes ratio, erythrocyte sedimentation rate, C-reactive protein, serum albumin and total bilirubin and indirect bilirubin levels. Urticaria activity score over 7 days (UAS-7) was calculated for the CSU patients. Forty patients with CSU and 55 healthy subjects were included in the study. Mean white blood cell (WBC) count is 8.37 ± 2.14 in the patients' group and 7.41 ± 2.01 in the healthy subjects group. Mean neutrophil (NEU) count is 4.88 ± 1.65 in the patients' group and 4.19 ± 1.39 in the healthy subjects group. Mean platelets (PLT) count is 308.48 ± 88.32 in the patients' group and 268.65 ± 64.80 in the healthy subjects group. We also detected positive correlations between UAS-7 score-WBC counts and UAS-7 score-NEU counts. Future studies are needed to investigate this possible relationship and confirm these results.

Cutaneous manifestations of HAV, HBV, HCV

Hepatotropic viral infections are a relevant global health problem and present multiple extrahepatic manifestations in addition to hepatic disease. Along with generic cutaneous symptoms correlated to the cholestatic liver disease that may arise during the infection, some cutaneous manifestations of hepatotropic viral infections are characteristic, enabling to suspect the underlying infection. This review will present the principal cutaneous manifestations of hepatotropic virus infection. Cutaneous manifestations are rare in HAV infections: these include urticaria, panniculitis, scarlatiniform eruption, evanescent skin rash, maculopapular prolonged rash, serum sickness-like illness rash, cutaneous vasculitis, cryoglobulinemia. The commonest cutaneous manifestation associated to HBV infection is serum sickness-like syndrome. Polyarteritis nodosa (PAN) is among the most common and serious cutaneous manifestations of HBV infection. In children, HBV infection may acutely manifest as papular acrodermatitis of childhood (Gianotti-Crosti Syndrome), with non-pruritic, non-coalescing, round papules. Patients with chronic HBV infection may also develop mixed cryoglobulinemia, that is, inter alia, the most documented extrahepatic manifestation of HCV infection. Cutaneous lichen planus has been associated to HBV and HCV infection. As for oral lichen planus, the association with HBV and HCV is more debated. Interestingly, patients with oral lichen planus with HCV have a higher risk of developing oral squamous cell carcinoma. Dermatologists should be aware of the possible cutaneous manifestations associated to viral hepatitis.

Comorbidity of viral hepatitis and chronic spontaneous urticaria: A systematic review

Chronic viral infections including those by hepatitis B (CHB) virus and hepatitis C (CHC) virus have been reported to be comorbidities of chronic spontaneous urticaria (CSU). Here, we performed the first comprehensive review of the peer-reviewed literature (PubMed, Web of Science and Google Scholar) on the prevalence of CHB and CHC in patients with CSU and vice versa. The prevalence of CHB and CHC in CSU does not appear to be increased. Less than 5% and 2% of patients with CSU have markers of CHB and CHC, respectively, according to most of the 32 studies reviewed. Urticarial rash including CSU occurs in ≤3% of patients with CHC as reported by most of 20 studies analysed. Very few patients have been assessed for the effects of antiviral hepatitis treatment on their CSU, and two but not all reportedly showed improvement. Hepatitis B/C infections appear unlikely to be linked to CSU. We suggest that routine screening for these infections in patients with CSU is not relevant or cost-effective and should not be performed unless liver function tests are abnormal, risk factors or symptoms of viral hepatitis are present, or urticarial vasculitis is suspected.