What the physicians should know about mast cells, dendritic cells, urticaria, and omalizumab during COVID-19 or asymptomatic infections due to SARS-CoV-2?

Chronic Spontaneous Urticaria Following mRNA COVID-19 Booster Vaccination at a Military Academy

Several adverse cutaneous reactions have been reported in the literature after SARS-CoV-2 vaccination with emerging reports on chronic spontaneous urticaria (CSU). However, there is little literature of chronic urticaria after COVID-19 boosters in a military population and the impact on operational readiness. We present a retrospective case series of CSU following Moderna COVID-19 booster vaccinations at the US Naval Academy (USNA). Demographics, clinical features, and impact on readiness were evaluated. Forty-nine students from the USNA were evaluated for urticaria after their third COVID-19 booster vaccination. Seventeen individuals were diagnosed with CSU. The median age was 20 years and predominantly male; the median time interval between vaccination and the onset of urticaria was 11 days. Out of 13 referred to Allergy, 7 patients had CU index performed and 2 were positive. Four patients received a second booster vaccination subsequently and did not have any exacerbation of symptoms. Symptoms were controlled with antihistamines, and none required immunomodulator or immunosuppressive therapies. All students were able to complete their commissioning, and none were referred for a medical board. In this series, USNA students who developed CSU after the mRNA COVID-19 Moderna booster vaccine did not have limitations from commissioning, duty status, or issues with subsequent COVID-19 vaccinations.

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.

Omalizumab may protect allergic patients against COVID-19: A systematic review

Omalizumab, which downregulates the immunoglobulin E (IgE) receptor site on plasmacytoid dendritic cells and thereby increases interferon-α (INF-α) production, may shorten the duration of viral infections by enhancing the antiviral immunity. A systematic review was conducted to investigate whether previous anti-IgE treatment with omalizumab could protect against SARS-CoV-2 disease ("COVID-19") (infection, disease duration, and severity), and whether IFN-α upregulation could be involved. The research included articles published from March 2020 to January 2022. An accurate search was performed on bibliographic biomedical database (MEDLINE - Pubmed, SCOPUS, EMBASE, BIOMED CENTRAL, Google scholar, COCHRANE LIBRARY, ClinicalTrial.gov) including cohorts, case reports and reviews. Different methods were used, based on the study design, to assess the quality of eligible studies. Several authors link omalizumab to a possible protection against viruses, but they often refer to studies carried out before the pandemic and with viruses other than SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) (eg, rhinoviruses -RV). Few cases of COVID-19 patients treated with omalizumab have been recorded, and, in most of them, no increased susceptibility to severe disease was observed. According to these data, the current indication is to continue omalizumab therapy during the pandemic. Moreover, although omalizumab may enhance the antiviral immune response even for SARS-CoV-2, further studies are needed to confirm this hypothesis. It would be helpful to establish a registry of omalizumab-treated (or in treatment) patients who have developed COVID-19. Finally, randomized controlled trials could be able to demonstrate the effect of omalizumab in protecting against severe SARS-CoV-2, through IFN-α upregulation or other immunological pathways.

Cellular immune states in SARS-CoV-2-induced disease

The general immune state plays important roles against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Cells of the immune system are encountering rapid changes during the acute phase of SARS-CoV-2-induced disease. Reduced fraction of functional CD8⁺ T cells, disrupted cross-talking between CD8⁺ T cells with dendritic cells (DCs), and impaired immunological T-cell memory, along with the higher presence of hyperactive neutrophils, high expansion of myeloid-derived suppressor cells (MDSCs) and non-classical monocytes, and attenuated cytotoxic capacity of natural killer (NK) cells, are all indicative of low efficient immunity against viral surge within the body. Immune state and responses from pro- or anti-inflammatory cells of the immune system to SARS-CoV-2 are discussed in this review. We also suggest some strategies to enhance the power of immune system against SARS-CoV-2-induced disease.

Relapse or worsening of chronic spontaneous urticaria during SARS-CoV-2 infection and vaccination in children: A telemedicine follow-up

BACKGROUND

Chronic urticaria (CU), characterized by daily wheals and/or angioedema lasting more than 6 weeks, is a common skin disease. CU is classified as spontaneous or inducible. Because of Coronavirus Disease-19 (COVID-19) pandemic, face-to-face visits were reduced, and many centers started remote consultations to minimize hospital admissions and risk for viral diffusion. Telemedicine became a valuable tool for evaluating and monitoring patients with chronic diseases, such as CU. This study aims to evaluate the effectiveness of telemedicine as a means for the follow-up of patients with chronic spontaneous urticaria (CSU) during the COVID-19 pandemic. In particular, we collected data related to CSU evolution and treatment by remote consultation. Moreover, we specifically investigated the impact of SARS-CoV-2 infection or vaccination on CSU in relapsing or worsening of such a disease.

METHODS

The electronic charts were reviewed for patients diagnosed with CSU, who were referred to the allergy unit of Meyer Children's Hospital, Florence. For each patient, a review of demographic characteristics, diagnostic workup, efficacy, and tolerability of the treatment was performed. Patients with a physical agent triggering CU were excluded from the study. Disease activity was monitored using the Urticaria Activity Score (UAS7). In addition, when the COVID-19 pandemic started, follow-up continued through telemedicine after an initial face-to-face visit when possible. Approximately 1 year after the diagnosis of CSU, patients were recontacted to investigate whether they had experienced a relapse or worsening of urticaria during a possible COVID-19 or immediately after receiving a COVID-19 vaccine.

RESULTS

From January 2020 to March 2021, 84 cases of CSU were identified, with 71 (84.5%) of these being evaluated via televisit (remote consultation). During the remote follow-up period, 38/71 (53.5%) patients who were evaluated via televisit recovered completely from CSU, while 24 (33.8%) made therapy adjustments, and 9 (12.7%) had to discontinue follow-up through remote visits and return to face-to-face visits. In February 2022, we recontacted the 71 patients with CSU, and 50 (70.4%) of them answered by phone call interview. Four (19.2%) of the 26 patients who had COVID-19 showed CSU relapse, while 1 (3.8%) had a CSU worsening. Instead, 1 (3.8%) patient of the 26 who were vaccinated had a relapse of CSU, and 1 (3.8%) had a worsening of CSU, both after the first dose.

CONCLUSION

Our data showed that telemedicine can be an effective tool for the follow-up of patients with CSU. Moreover, COVID-19, as well as COVID-19 vaccination, may trigger CSU relapse or worsening, but both are unspecific triggers, and urticaria shows a very short duration in most cases.

Evaluating immunohaematological profile among COVID-19 active infection and recovered patients in Ghana

Introduction

The rapid spread of COVID-19 has been a global public health problem and it is yet to be put under control. Active COVID-19 is associated with unrestrained secretion of pro-inflammatory cytokines and imbalances in haematological profile including anaemia, leukocytosis and thrombocytopaenia. However, the haematological profile and immune status following recovery from COVID-19 has not been recognized. We evaluated the immunohaematological profile among COVID-19 patients with active infection, recovered cases and unexposed healthy individuals in the Ashanti region of Ghana.

Methodology

A total of 95 adult participants, consisting of 35 positive, 30 recovered and 30 unexposed COVID-19 negative individuals confirmed by RT-PCR were recruited for the study. All the patients had the complete blood count performed using the haematological analyzer Sysmex XN-1500. Their plasma cytokine levels of interleukin (IL)-1β, IL-6, IL-10, IL-17, tumour necrosis factor-alpha (TNF-α) and interferon gamma (IFN-γ) were analysed using ELISA. Statistical analyses were performed on R statistical software.

Result

The Patients with COVID-19 active infection had significantly higher levels of IL10 (181±6.14 pg/mL vs 155.00±14.32 pg/mL vs 158.80±11.70 pg/mL, p = 0.038), WBC count (5.5±0.4 x10⁹ /L vs 4.5±0.6 x10⁹ /L vs 3.8±0.5, p < 0.0001) and percentage basophil (1.8±0.1% vs 0.8±0.3% vs 0.7±0.2%, p = 0.0040) but significantly lower levels of IFN-γ (110.10±9.52 pg/mL vs 142.80±5.46 pg/mL vs 140.80±6.39 pg/mL, p = 0.021), haematocrit (24.1±3.7% vs 38.3± 3.0% vs 38.5±2.2%, p < 0.0001), haemoglobin concentration (9.4±0.1g/dl vs 12.5± 5.0g/dl vs 12.7±0.8, p < 0.0001) and MPV (9.8±0.2fL vs 11.1±0.5fL vs 11.6±0.3fL, p < 0.0001) compared to recovered and unexposed controls respectively. There were significant association between IL-1β & neutrophils (r = 0.42, p<0.05), IL-10 & WBC (r = 0.39, p<0.05), IL-10 & Basophils (r = -0.51, p<0.01), IL-17 & Neutrophil (r = 0.39, p<0.05) in the active COVID-19 cases.

Conclusion

COVID-19 active infection is associated with increased IL-10 and WBC with a concomitant decrease in IFN-γ and haemoglobin concentration. However, recovery from the disease is associated with immune recovery with appareantly normal haematological profile.

Insights into urticaria in pediatric and adult populations and its management with fexofenadine hydrochloride

OBJECTIVE

The present narrative review provides a comprehensive update of the current knowledge on urticaria, both in adult and pediatric populations, and on the safety and efficacy of fexofenadine hydrochloride (HCl) as a treatment option.

DATA SOURCE

A literature search was conducted on Embase and Medline.

STUDY SELECTION

Clinical studies published in English and published between 1999 and 2020 were selected.

RESULTS

Although the exact pathogenesis of urticaria is not fully understood, multiple pathways of mast cell activation are discussed to explain the existence of phenotypically different clinical manifestations of urticaria. An overview of the worldwide prevalence of chronic urticaria, including disease burden and patient's quality of life is provided. The impact of urticaria on patient's life differs on the basis of whether its form is acute or chronic, but pharmacological approaches are most often needed to control the disabling symptoms. A summary of the current management of urticaria recommended by different guidelines across countries (Global; European; American; Australian; Asian; Japanese) is presented. Non-sedating, second-generation H₁-antihistamines are the preferred choice of treatment across several guidelines worldwide. Herein, the efficacy and safety of fexofenadine HCl, a representative second-generation H₁-antihistamine approved for the treatment of urticaria, is discussed. The occurrence of urticaria manifestations in COVID-19 patients is also briefly presented.

CONCLUSION

The burden of acute and chronic urticaria is high for patients. Second generation anti-histamines such as fexofenadine HCl can help managing the symptoms.

COVID-19 scenario and recommendations on the continuity of immunobiological therapy in patients with atopic asthma in Brazil and Latin America

INTRODUCTION

With the abrupt establishment of the COVID-19 pandemic, treatment for immunological diseases may be influenced by the SARS-CoV-2 infection, including asthma and other allergies. Immunobiologics play a pivotal role in the management of severe symptoms of allergy and an opinion regarding the continuity of this treatment during the COVID-19 pandemic must be issued.

AREAS COVERED

In Brazil and other countries, patients with severe asthma were included in the priority groups for COVID-19 vaccination, even those who are undergoing immunobiological therapy. Data are insufficient to support the influence of this therapy on severe COVID-19 as targeting molecules may play a role in the physiopathology of the infection. Therapeutic strategies for asthma and guidelines/statements of the main societies of Allergy in Latin America on the continuity of treatment with immunobiologics during the COVID-19 pandemic were obtained from the institutional websites, PubMed, Scielo, Google Scholar, and CINAHL electronic platforms by searching for papers published up to September 2021.

EXPERT OPINION

Although the association between asthma and COVID-19 has been under investigation, immunobiological treatment should follow the consensus-based statements recommending the maintenance of the therapy unless the patient is infected by the SARS-CoV-2. However, it must be closely followed by the medical assistant.

Impact of Anti-Type 2 Inflammation Biologic Therapy on COVID-19 Clinical Course and Outcome

SARS-CoV-2 pandemic had a general and deep impact on the clinical management of chronic diseases, including respiratory and allergic disorders. At the beginning of the pandemic, one of the main concerns was the potential impact of immunosuppressive/immunomodulatory drugs on COVID-19 clinical course. In this review, we aim to summarize and analyze the available clinical evidence from patients treated with anti-type 2 inflammation biologics (including anti-IgE, anti-IL-5 and anti-IL-4 agents), who developed COVID-19. Overall, the treatment with anti-Th2 biologics can be considered safe during COVID-19. It does not worsen the clinical course and outcome of COVID-19, and it may be actually protective somehow from developing severe forms. Moreover, patients treated with these biological agents do not seem to be more prone to get infected by SARS-CoV-2.

The effect of COVID-19 on patients with chronic spontaneous urticaria treated with omalizumab and antihistamines: A cross-sectional, comparative study

Introduction

Chronic spontaneous urticaria (CSU) is defined as recurrent attacks of urticaria present for more than six weeks. The monoclonal anti‐immunoglobulin E antibody, omalizumab, was approved for the treatment of CSU in patients who remain refractory to H1‐antihistamines. Biologic agents are shown not to increase the risk of COVID‐19 infection in different studies.

Objective

In the present study, we aimed to determine the prevalance of COVID‐19 infection in relation to the age, gender, presence of other comorbidities, and treatment given for CSU.

Methods

We conducted a descriptive cross‐sectional study of 233 patients diagnosed with CSU in a tertiary referral hospital. Demographical data, treatment given for CSU, the presence of COVID‐19‐related symptoms, history of close contact to a person with COVID‐19 and COVID‐19 real‐time polymerase chain reaction (RT‐PCR) results were determined via a telephone survey and checked from medical data records.

Results

One hundred sixty patients were female; whereas 73 were male. The mean age was 44.76. Out of 233 patients with chronic urticaria, 125 had symptoms related to COVID‐19 infection. RT‐PCR testing for COVID‐19 was performed in 156 patients. Of 156 patients with COVID‐19 RT‐PCR test, RT‐PCR result was positive in 15 cases.

Conclusions

No statistically significant relationship was found between COVID‐19 RT‐PCR positivity and the type of treatment administered for chronic urticaria when the patients are divided into omalizumab ± oral antihistamines and only oral antihistamines treatment groups (p = 0.150). Omalizumab seems to be safe in the era of COVID‐19.

COVID-19 Disease Leading to Chronic Spontaneous Urticaria Exacerbation: A Romanian Retrospective Study

(1) Background: The COVID-19 pandemic has resulted in the exacerbation of various chronic diseases. Due to the potential impact of SARS-CoV-2 on mast cells, we aimed to analyze the relevance of COVID-19 disease on chronic spontaneous urticaria (CSU) clinical presentation and biological profile. (2) Methods: This study is a retrospective case series of patients with CSU diagnosed and treated in the Allergy Department of the Professor Doctor Octavian Fodor RIGH, (Cluj-Napoca, Romania). Patients were assessed for disease activity and level of control with the weekly urticaria activity score and the visual analogue scale. Results were correlated with COVID-19 severity and with nonspecific markers of inflammation during and after the SARS-CoV-2 infection. (3) Results: SARS-CoV-2 impacted a significant proportion (33%) of the CSU patients, of which 71% developed a moderate-severe form of COVID-19. Most of the patients (68%) had moderate-severe forms of CSU and 65% took AH1 treatment (one dose, two-fold dose or four-fold dose). The rest of them (35%) received the second-line treatment (40.3% Omalizumab, 53% Prednisolone and 4.8% Cyclosporine). In Omalizumab treated group of UCS patients we observed that COVID-19 disease was not severe. We established a positive correlation between the severity of the infection and that of the CSU clinical presentation, with most bothersome symptoms of urticaria being experienced by moderate to severe COVID-19 CSU patients (47%). Inflammatory markers were positively correlated (p = 0.01) with a more severe clinical profile of CSU, in accordance with our hypothesis that the level of inflammation triggered by COVID-19 disease has a role in CSU exacerbation. The non-specific inflammatory markers, such as CRP, were positively associated with the UAS7 score (R2 = 0.363; p = 0.001). An increased rate of exacerbation of CSU was observed in moderate-severe COVID-19 infection. (4) Conclusions: COVID-19 disease can result in the exacerbation of chronic spontaneous urticaria, more likely in moderate to severe forms of infection.

Prominent Cutaneous Manifestation of COVID-19: A Case Report

Extrapulmonary signs of coronavirus disease are becoming an important tool for patient diagnosis; this is particularly true for skin manifestations as they are visible to both the patient and physician. In this case report, the authors describe a case in which cutaneous manifestations were the most noticeable and prominent symptom in a patient with coronavirus disease.

A small molecule compound berberine as an orally active therapeutic candidate against COVID-19 and SARS: A computational and mechanistic study

The novel coronavirus disease, COVID-19, has grown into a global pandemic and a major public health threat since its breakout in December 2019. To date, no specific therapeutic drug or vaccine for treating COVID-19 and SARS has been FDA approved. Previous studies suggest that berberine, an isoquinoline alkaloid, has shown various biological activities that may help against COVID-19 and SARS, including antiviral, anti-allergy and inflammation, hepatoprotection against drug- and infection-induced liver injury, as well as reducing oxidative stress. In particular, berberine has a wide range of antiviral activities such as anti-influenza, anti-hepatitis C, anti-cytomegalovirus, and anti-alphavirus. As an ingredient recommended in guidelines issued by the China National Health Commission for COVID-19 to be combined with other therapy, berberine is a promising orally administered therapeutic candidate against SARS-CoV and SARS-CoV-2. The current study comprehensively evaluates the potential therapeutic mechanisms of berberine in preventing and treating COVID-19 and SARS using computational modeling, including target mining, gene ontology enrichment, pathway analyses, protein-protein interaction analysis, and in silico molecular docking. An orally available immunotherapeutic-berberine nanomedicine, named NIT-X, has been developed by our group and has shown significantly increased oral bioavailability of berberine, increased IFN-γ production by CD8+ T cells, and inhibition of mast cell histamine release in vivo, suggesting a protective immune response. We further validated the inhibition of replication of SARS-CoV-2 in lung epithelial cells line in vitro (Calu3 cells) by berberine. Moreover, the expression of targets including ACE2, TMPRSS2, IL-1α, IL-8, IL-6, and CCL-2 in SARS-CoV-2 infected Calu3 cells were significantly suppressed by NIT-X. By supporting protective immunity while inhibiting pro-inflammatory cytokines; inhibiting viral infection and replication; inducing apoptosis; and protecting against tissue damage, berberine is a promising candidate in preventing and treating COVID-19 and SARS. Given the high oral bioavailability and safety of berberine nanomedicine, the current study may lead to the development of berberine as an orally, active therapeutic against COVID-19 and SARS.

Immunological Aspects Related to Viral Infections in Severe Asthma and the Role of Omalizumab

Viral respiratory infections are recognized risk factors for the loss of control of allergic asthma and the induction of exacerbations, both in adults and children. Severe asthma is more susceptible to virus-induced asthma exacerbations, especially in the presence of high IgE levels. In the course of immune responses to viruses, an initial activation of innate immunity typically occurs and the production of type I and III interferons is essential in the control of viral spread. However, the Th2 inflammatory environment still appears to be protective against viral infections in general and in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections as well. As for now, literature data, although extremely limited and preliminary, show that severe asthma patients treated with biologics don't have an increased risk of SARS-CoV-2 infection or progression to severe forms compared to the non-asthmatic population. Omalizumab, an anti-IgE monoclonal antibody, exerts a profound cellular effect, which can stabilize the effector cells, and is becoming much more efficient from the point of view of innate immunity in contrasting respiratory viral infections. In addition to the antiviral effect, clinical efficacy and safety of this biological allow a great improvement in the management of asthma.

Aripiprazole as a Candidate Treatment of COVID-19 Identified Through Genomic Analysis

Background: Antipsychotics modulate expression of inflammatory cytokines and inducible inflammatory enzymes. Elopiprazole (a phenylpiperazine antipsychotic drug in phase 1) has been characterized as a therapeutic drug to treat SARS-CoV-2 infection in a repurposing study. We aim to investigate the potential effects of aripiprazole (an FDA approved phenylpiperazine) on COVID-19-related immunological parameters. Methods: Differential gene expression profiles of non-COVID-19 vs. COVID-19 RNA-Seq samples (CRA002390 project in GSA database) and drug-naïve patients with non-affective psychosis at baseline and after three months of aripiprazole treatment were identified. An integrative transcriptomic analyses of aripiprazole effects on differentially expressed genes in COVID-19 patients was performed. Findings: 82 out the 377 genes (21.7%) with expression significantly altered by aripiprazole have also their expression altered in COVID-19 patients and in 93.9% of these genes their expression is reverted by aripiprazole. The number of common genes with expression altered in both analyses is significantly higher than expected (Fisher's Exact Test, two tail; p value = 3.2e-11). 11 KEGG pathways were significantly enriched with genes with altered expression both in COVID-19 patients and aripiprazole medicated non-affective psychosis patients (p adj<0.05). The most significant pathways were associated to immune responses and mechanisms of hyperinflammation-driven pathology (i.e.,"inflammatory bowel disease (IBD)" (the most significant pathway with a p adj of 0.00021), "Th1 and Th2 cell differentiation" and "B cell receptor signaling pathway") that have been also associated with COVID19 clinical outcome. Interpretation: This exploratory investigation may provide further support to the notion that a protective effect is exerted by aripiprazole (phenylpiperazine) by modulating the expression of genes that have shown to be altered in COVID-19 patients. Along with many ongoing studies and clinical trials, repurposing available medications could be of use in countering SARS-CoV-2 infection, but require further studies and trials.

Immunologic Pathophysiology and Airway Remodeling Mechanism in Severe Asthma: Focused on IgE-Mediated Pathways

Despite the expansion of the understanding in asthma pathophysiology and the continual advances in disease management, a small subgroup of patients remains partially controlled or refractory to standard treatments. Upon the identification of immunoglobulin E (IgE) and other inflammatory mediators, investigations and developments of targeted agents have thrived. Omalizumab is a humanized monoclonal antibody that specifically targets the circulating IgE, which in turn impedes and reduces subsequent releases of the proinflammatory mediators. In the past decade, omalizumab has been proven to be efficacious and well-tolerated in the treatment of moderate-to-severe asthma in both trials and real-life studies, most notably in reducing exacerbation rates and corticosteroid use. While growing evidence has demonstrated that omalizumab may be potentially beneficial in treating other allergic diseases, its indication remains confined to treating severe allergic asthma and chronic idiopathic urticaria. Future efforts may be bestowed on determining the optimal length of omalizumab treatment, seeking biomarkers that could better predict treatment response and as well as extending its indications.

The impact of COVID-19 pandemic on the management of patients with chronic urticaria: An observational two-center study from Turkey

The Coronavirus Disease 2019 (COVID‐19) outbreak significantly affected the clinical practice in hospitals and the management of many diseases. The aim of this study was to evaluate the effect of pandemic‐related factors on the severity and course of chronic urticaria (CU). A total of 194 CU patients who were on regular follow‐up, were enrolled in the study. The disease activity was assessed by means of the weekly urticaria activity score (UAS7) and urticaria control test (UCT). Patients were divided into two subgroups according to their disease aggravation as “aggravated” and “non‐aggravated”. Two groups were compared in terms of demographic, clinical, COVID‐19‐associated parameters, and parameters related with the effect of COVID‐19 pandemic on CU management. The omalizumab use was statistically higher (P = .017), and the systemic corticosteroid use was statistically lower (P = .025) in the “aggravated” group. Adherence to quarantine was significantly lower in the “aggravated” group (P = .027). 173 patients (89.2%) were unable to contact a dermatologist during the pandemic. Among 186 patients who received treatment for CU before the pandemic, 48 (25.8%) did not continue the existing treatment during the pandemic. CU aggravated in one patient with COVID‐19 and remained stable in the other. This study showed that CU patients, especially those on omalizumab therapy, had difficulties in attending medical care and even in the maintenance of their existing therapies during the pandemic. Creating novel follow‐up and treatment models as well as the increased use of teledermatology might be beneficial in the management of this life‐disturbing condition.

Covid-19 hyperinflammation and post-Covid-19 illness may be rooted in mast cell activation syndrome

OBJECTIVES

One-fifth of Covid-19 patients suffer a severe course of Covid-19 infection; however, the specific causes remain unclear. Mast cells (MCs) are activated by SARS-CoV-2. Although only recently recognized, MC activation syndrome (MCAS), usually due to acquired MC clonality, is a chronic multisystem disorder with inflammatory and allergic themes, and an estimated prevalence of 17%. This paper describes a novel conjecture explaining how MCAS might cause a propensity for severe acute Covid-19 infection and chronic post-Covid-19 illnesses.

METHODS

Observations of Covid-19 illness in patients with/without MCAS were compared with extensive clinical experience with MCAS.

RESULTS

The prevalence of MCAS is similar to that of severe cases within the Covid-19-infected population. Much of Covid-19's hyperinflammation is concordant with manners of inflammation which MC activation can drive. Drugs with activity against MCs or their mediators have preliminarily been observed to be helpful in Covid-19 patients. None of the authors' treated MCAS patients with Covid-19 suffered severe infection, let alone mortality.

CONCLUSIONS

Hyperinflammatory cytokine storms in many severely symptomatic Covid-19 patients may be rooted in an atypical response to SARS-CoV-2 by the dysfunctional MCs of MCAS rather than a normal response by normal MCs. If proven, this theory has significant therapeutic and prognostic implications.