Pathophysiology of Post-COVID syndromes: a new perspective.

Most COVID-19 patients recovered with low mortality; however, some patients experienced long-term symptoms described as "long-COVID" or "Post-COVID syndrome" (PCS). Patients may have persisting symptoms for weeks after acute SARS-CoV-2 infection, including dyspnea, fatigue, myalgia, insomnia, cognitive and olfactory disorders. These symptoms may last for months in some patients. PCS may progress in association with the development of mast cell activation syndrome (MCAS), which is a distinct kind of mast cell activation disorder, characterized by hyper-activation of mast cells with inappropriate and excessive release of chemical mediators. COVID-19 survivors, mainly women, and patients with persistent severe fatigue for 10 weeks after recovery with a history of neuropsychiatric disorders are more prone to develop PCS. High D-dimer levels and blood urea nitrogen were observed to be risk factors associated with pulmonary dysfunction in COVID-19 survivors 3 months post-hospital discharge with the development of PCS. PCS has systemic manifestations that resolve with time with no further complications. However, the final outcomes of PCS are chiefly unknown. Persistence of inflammatory reactions, autoimmune mimicry, and reactivation of pathogens together with host microbiome alterations may contribute to the development of PCS. The deregulated release of inflammatory mediators in MCAS produces extraordinary symptoms in patients with PCS. The development of MCAS during the course of SARS-CoV-2 infection is correlated to COVID-19 severity and the development of PCS. Therefore, MCAS is treated by antihistamines, inhibition of synthesis of mediators, inhibition of mediator release, and inhibition of degranulation of mast cells.

Urticaria relapse after mRNA COVID-19 vaccines in patients affected by chronic spontaneous urticaria and treated with antihistamines plus omalizumab: A single-center experience.

Urticaria is a disease characterized by wheals and/or angioedema. Chronic spontaneous urticaria (CSU) occurs for longer than 6 weeks and appears independently of any identifiable exogenous stimulus. During the vaccination campaign for Coronavirus disease 2019 (COVID-19) pandemic, several cutaneous adverse events have been described, among which urticaria lasting less than 6 weeks (acute urticaria, AU). AU due to vaccines can be IgE or non-IgE mediated; the former typically develop within 4 h of drug exposure, the latter occurs later and the mechanism is unclear. In this retrospective study we analyzed the frequency and clinical characteristics of urticaria occurring after COVID-19 vaccine (post-vaccination urticaria relapse) in adult CSU patients treated with antihistamine and omalizumab, and in clinical remission.

Combinational benefit of antihistamines and remdesivir for reducing SARS-CoV-2 replication and alleviating inflammation-induced lung injury in mice.

COVID-19 is an immune-mediated inflammatory disease caused by SARS-CoV-2 infection, the combination of anti-inflammatory and antiviral therapy is predicted to provide clinical benefits. We recently demonstrated that mast cells (MCs) are an essential mediator of SARS-CoV-2-initiated hyperinflammation. We also showed that spike protein-induced MC degranulation initiates alveolar epithelial inflammation for barrier disruption and suggested an off-label use of antihistamines as MC stabilizers to block degranulation and consequently suppress inflammation and prevent lung injury. In this study, we emphasized the essential role of MCs in SARS-CoV-2-induced lung lesions in vivo, and demonstrated the benefits of co-administration of antihistamines and antiviral drug remdesivir in SARS-CoV-2-infected mice. Specifically, SARS-CoV-2 spike protein-induced MC degranulation resulted in alveolar-capillary injury, while pretreatment of pulmonary microvascular endothelial cells with antihistamines prevented adhesion junction disruption; predictably, the combination of antiviral drug remdesivir with the antihistamine loratadine, a histamine receptor 1 (HR1) antagonist, dampened viral replication and inflammation, thereby greatly reducing lung injury. Our findings emphasize the crucial role of MCs in SARS-CoV-2-induced inflammation and lung injury and provide a feasible combination antiviral and anti-inflammatory therapy for COVID-19 treatment.

Delayed systemic urticarial reactions following mRNA COVID-19 vaccination.

Background: As the vaccination campaign in response to the coronavirus disease 2019 (COVID-19) pandemic continues, concerns with regard to adverse reactions to the vaccine remain. Although immediate hypersensitivity reactions have received much attention, delayed systemic urticarial reactions after vaccination can occur. Objective: To describe the clinical presentation, vaccine excipient skin testing results, and outcomes of subsequent COVID-19 vaccination in patients who experienced delayed systemic urticarial reactions after messenger RNA (mRNA) COVID-19 vaccination. Methods: This was a retrospective case series of 12 patients referred to the Mayo Clinics in Rochester, Minnesota, and Jacksonville, Florida, between January 19, 2021, and April 30, 2021, for evaluation of delayed systemic urticarial reactions after mRNA COVID-19 vaccination. Demographics, medical and allergic history, reaction details, vaccine excipient skin testing results (when performed), and the outcome after subsequent vaccination were collected for each patient. Results: The mean age of the patients was 52 years, all were white, and 9 (75%) were women. Half of the patients had a history of drug allergy, and one had a history of chronic spontaneous urticaria. Seven patients reacted to the Pfizer-BioNTech vaccine and five reacted to the Moderna vaccine. Seven patients developed symptoms between 8 and 24 hours after vaccination. Nine patients required antihistamines for treatment. The median time to symptom resolution was 4 days. Nine patients underwent allergist-directed COVID-19 vaccine excipient skin testing, all of which were negative. Ten patients chose to receive their next mRNA COVID-19 vaccine dose, and four patients experienced recurrent delayed urticaria. Conclusion: Delayed systemic urticarial reactions after mRNA COVID-19 vaccination were not life-threatening, could be treated with antihistamines, and were not predicted with vaccine excipient skin testing. They were not a contraindication to subsequent vaccination, although patients should be counseled with regard to the possibility of recurrence.

Leukocytoclastic vasculitis after COVID-19 vaccination.

Leukocytoclastic vasculitis (LCV) is the vasculitis of small vessels. In this report, we describe a 38-year-old male patient who presented to our outpatient clinic with a 1-week history of rash on his lower extremities that had started 4 days after receiving the Pfizer-BioNTech SARS-CoV-2 vaccine. A diagnosis of LCV was made based on clinical and histopathological findings. The patient was treated with antihistamines and prednisolone, after which improvement was observed in the lesions. With this paper, we aim to raise awareness concerning the possibility of LCV development after COVID-19 vaccination.

Long COVID following mild SARS-CoV-2 infection: characteristic T cell alterations and response to antihistamines.

Long COVID is characterized by the emergence of multiple debilitating symptoms following SARS-CoV-2 infection. Its etiology is unclear and it often follows a mild acute illness. Anecdotal reports of gradual clinical responses to histamine receptor antagonists (HRAs) suggest a histamine-dependent mechanism that is distinct from anaphylaxis, possibly mediated by T cells, which are also regulated by histamine. T cell perturbations have been previously reported in post-viral syndromes, but the T cell landscape in patients who have recovered from mild COVID-19 and its relationship to both long COVID symptoms and any symptomatic response to HRA remain underexplored. We addressed these questions in an observational study of 65 individuals who had recovered from mild COVID-19. Participants were surveyed between 87 and 408 days after the onset of acute symptoms; none had required hospitalization, 16 had recovered uneventfully, and 49 had developed long COVID. Symptoms were quantified using a structured questionnaire and T cell subsets enumerated in a standard diagnostic assay. Patients with long-COVID had reduced CD4+ and CD8+ effector memory (EM) cell numbers and increased PD-1 (programmed cell death protein 1) expression on central memory (CM) cells, whereas the asymptomatic participants had reduced CD8+ EM cells only and increased CD28 expression on CM cells. 72% of patients with long COVID who received HRA reported clinical improvement, although T cell profiling did not clearly distinguish those who responded to HRA. This study demonstrates that T cell perturbations persist for several months after mild COVID-19 and are associated with long COVID symptoms.

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.

Delayed skin reaction after mRNA-1273 vaccine against SARS-CoV-2: a rare clinical reaction.

BACKGROUND: The coronavirus disease 2019 (COVID-19) is associated with a wide clinical spectrum of skin manifestations, including urticarial, vesicular, vasculitic and chilblain-like lesions. Recently, delayed skin reactions have been reported in 1% individuals following mRNA vaccination against SARS-CoV-2. The exact pathophysiology and the risk factors still remain unclear. PATIENTS AND METHODS: 6821 employees and patients were vaccinated at our institutions between February and June 2021. Every patient received two doses of the mRNA-1273 vaccine in our hospitals, and reported back in case of any side effects which were collected in our hospital managed database. RESULTS: Eleven of 6821 vaccinated patients (0.16%) developed delayed skin reactions after either the first or second dose of the mRNA-1273 vaccine against SARS-CoV-2. Eight of 11 patients (73%) developed a rash after the first dose, while in 3/11 (27%), the rash occurred after the second dose. More females (9/11) were affected. Four of 11 patients required antihistamines, with two needing additional topical steroids. All the cutaneous manifestations resolved within 14 days. None of the skin reactions after the first dose of the vaccine prevented the administration of the second dose. There were no long-term cutaneous sequelae in any of the affected individuals. CONCLUSION: Our data suggests that skin reactions after the use of mRNA-1273 vaccine against SARS-CoV-2 are possible, but rare. Further studies need to be done to understand the pathophysiology of these lesions.

Famotidine inhibits toll-like receptor 3-mediated inflammatory signaling in SARS-CoV-2 infection.

Apart from prevention using vaccinations, the management options for COVID-19 remain limited. In retrospective cohort studies, use of famotidine, a specific oral H2 receptor antagonist (antihistamine), has been associated with reduced risk of intubation and death in patients hospitalized with COVID-19. In a case series, nonhospitalized patients with COVID-19 experienced rapid symptom resolution after taking famotidine, but the molecular basis of these observations remains elusive. Here we show using biochemical, cellular, and functional assays that famotidine has no effect on viral replication or viral protease activity. However, famotidine can affect histamine-induced signaling processes in infected Caco2 cells. Specifically, famotidine treatment inhibits histamine-induced expression of Toll-like receptor 3 (TLR3) in SARS-CoV-2 infected cells and can reduce TLR3-dependent signaling processes that culminate in activation of IRF3 and the NF-κB pathway, subsequently controlling antiviral and inflammatory responses. SARS-CoV-2-infected cells treated with famotidine demonstrate reduced expression levels of the inflammatory mediators CCL-2 and IL6, drivers of the cytokine release syndrome that precipitates poor outcome for patients with COVID-19. Given that pharmacokinetic studies indicate that famotidine can reach concentrations in blood that suffice to antagonize histamine H2 receptors expressed in mast cells, neutrophils, and eosinophils, these observations explain how famotidine may contribute to the reduced histamine-induced inflammation and cytokine release, thereby improving the outcome for patients with COVID-19.

Angioedema: differential diagnosis and acute management.

A clinical vignette illustrates a typical presentation of a patient seeking help for acute angioedema. Despite the risks of SARS-CoV-2 (COVID-19) exposure, it is critical to evaluate patients with acute angioedema in person, because there is always the potential for angioedema to progress to the head, neck, or lungs, which can rapidly compromise the airways and require immediate intervention to avoid potential asphyxiation. There are three mediators of angioedema, histamine, leukotriene, or bradykinin, each requiring different management. This article provides clinicians essential information for differentiating between these types of angioedema, including an overview of the underlying pathogenies of angioedema, and the subjective and objective findings that are useful in differentiating between angioedema types. The article ends with the appropriate management for each type of acute angioedema, including the medications approved by the FDA for on-demand treatment of an HAE attack.

Delayed Localized Hypersensitivity Reactions to the Moderna COVID-19 Vaccine: A Case Series.

Importance: In response to the coronavirus disease 2019 (COVID-19) pandemic, 2 mRNA vaccines (Pfizer-BioNTech and Moderna) received emergency use authorization from the US Food and Drug Administration in December 2020. Some patients in the US have developed delayed localized cutaneous vaccine reactions that have been dubbed "COVID arm." Objective: To describe the course of localized cutaneous injection-site reactions to the Moderna COVID-19 vaccine, subsequent reactions to the second vaccine dose, and to characterize the findings of histopathologic examination of the reaction. Design, Setting, and Participants: This retrospective case series study was performed at Yale New Haven Hospital, a tertiary medical center in New Haven, Connecticut, with 16 patients referred with localized cutaneous injection-site reactions from January 20 through February 12, 2021. Main Outcomes and Measures: We collected each patient's demographic information, a brief relevant medical history, clinical course, and treatment (if any); and considered the findings of a histopathologic examination of 1 skin biopsy specimen. Results: Of 16 patients (median [range] age, 38 [25-89] years; 13 [81%] women), 14 patients self-identified as White and 2 as Asian. The delayed localized cutaneous reactions developed in a median (range) of 7 (2-12) days after receiving the Moderna COVID-19 vaccine. These reactions occurred at or near the injection site and were described as pruritic, painful, and edematous pink plaques. None of the participants had received the Pfizer-BioNTech vaccine. Results of a skin biopsy specimen demonstrated a mild predominantly perivascular mixed infiltrate with lymphocytes and eosinophils, consistent with a dermal hypersensitivity reaction. Of participants who had a reaction to first vaccine dose (15 of 16 patients), most (11 patients) developed a similar localized injection-site reaction to the second vaccine dose; most (10 patients) also developed the second reaction sooner as compared with the first-dose reaction. Conclusions and Relevance: Clinical and histopathologic findings of this case series study indicate that the localized injection-site reactions to the Moderna COVID-19 vaccine are a delayed hypersensitivity reaction. These reactions may occur sooner after the second dose, but they are self-limited and not associated with serious vaccine adverse effects. In contrast to immediate hypersensitivity reactions (eg, anaphylaxis, urticaria), these delayed reactions (dubbed "COVID arm") are not a contraindication to subsequent vaccination.

Severe urticarial rash as the initial symptom of COVID-19 infection.

A 54-year-old woman presented with pruritic rash and hives of 3 days' duration followed by shortness of breath for 1 day. SARS-CoV-2 PCR test for COVID-19 was positive. Cutaneous manifestations of COVID-19 include acral lesions, urticarial rash, erythematous maculopapular rash, vascular rashes and vesicular rash. The cutaneous manifestations are mostly described as self-limiting. Urticarial rashes are not reported as the initial presentation symptom of COVID-19 infection but mostly noted to occur at the same time or after the onset of non-cutaneous symptoms. Management of cutaneous manifestations of COVID-19 affecting quality of life has not been well studied. Antihistamine therapy is the primary recommended therapy. Role of antiviral therapy for severe cases of rash needs to be further assessed.

Identification of antiviral antihistamines for COVID-19 repurposing.

There is an urgent need to identify therapies that prevent SARS-CoV-2 infection and improve the outcome of COVID-19 patients. Although repurposed drugs with favorable safety profiles could have significant benefit, widely available prevention or treatment options for COVID-19 have yet to be identified. Efforts to identify approved drugs with in vitro activity against SARS-CoV-2 resulted in identification of antiviral sigma-1 receptor ligands, including antihistamines in the histamine-1 receptor binding class. We identified antihistamine candidates for repurposing by mining electronic health records of usage in population of more than 219,000 subjects tested for SARS-CoV-2. Usage of diphenhydramine, hydroxyzine and azelastine was associated with reduced incidence of SARS-CoV-2 positivity in subjects greater than age 61. We found diphenhydramine, hydroxyzine and azelastine to exhibit direct antiviral activity against SARS-CoV-2 in vitro. Although mechanisms by which specific antihistamines exert antiviral effects is not clear, hydroxyzine, and possibly azelastine, bind Angiotensin Converting Enzyme-2 (ACE2) and the sigma-1 receptor as off-targets. Clinical studies are needed to measure the effectiveness of diphenhydramine, hydroxyzine and azelastine for disease prevention, for early intervention, or as adjuvant therapy for severe COVID-19.

General health status of children with asthma during the COVID-19 pandemic.

BACKGROUND: Since the COVID-19 pandemic became a serious health concern globally, patients with chronic diseases have required close attention with regard to general risks and individual treatment. We aimed to reveal the general health status of pediatric asthmatic patients during the pandemic, considering the role of household factors in parental attitudes. METHODS: We asked 60 asthmatic patients and their parents to respond to a questionnaire, with the aim of revealing the current health status of the patients and the general approach of the family to asthma management during the pandemic. RESULTS: A total of eight patients had had an asthma attack during the outbreak, but there was no confirmed correlation with COVID-19 infection. Most of the parents had never considered stopping their children's current medications. However, the majority of them reported concerns about the failure of the ambulatory care services and almost all saw their children as being at high risk for COVID-19 infection. There was no significant relationship between these concerns and their psychological status (P > 0.05). CONCLUSIONS: The crucial point regarding asthma management is to control patients' medical and psychological status to minimize the effects of the pandemic. Healthcare professionals should also pay attention to members of the patients' households because their adaptation to the "new normal" of pandemic may directly affect the patients' state of health.