Mark G Kirchhof

Mark G Kirchhof
University of Ottawa · Department of Medicine

About

83
Publications
11,795
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
1,847
Citations

Publications

Publications (83)
Article
Full-text available
Background: People living with human immunodeficiency virus (PLHIV) have a similar prevalence of psoriasis as the general population, though incidence and severity correlate with HIV viral load. Adequately treating HIV early renders the infection a chronic medical condition and allows PLHIV with a suppressed viral load (PLHIV-s) to live normal liv...
Article
Full-text available
Introduction Vaccines for SARS-CoV-2 have been accessible to the public since December 2020. However, only 58.3% of Americans are fully vaccinated as of 5 November 2021. Numerous studies have supported YouTube as a source of both reliable and misleading information during the COVID-19 pandemic. Misinformation regarding the safety and efficacy of CO...
Article
Full-text available
IntroductionPsoriasis (Pso) is a common, immune-mediated, chronic-relapsing, inflammatory skin disease. While a great deal is known about Pso and its treatment, there remain several treatment scenarios unaddressed by clinical studies. To be effective, treatment for Pso must alter the activity of one or more immunological pathways important in the p...
Article
Background: Since its legalization in Canada, cannabis use has expanded to include commercially available topical formations. Several scientifically unsupported claims regarding the therapeutic efficacy of topical cannabis are also being made. Developing an understanding of the consumer uses of topical cannabis is important for clinicians to provi...
Article
Full-text available
Introduction Hidradenitis Suppurativa (HS) is a chronic inflammatory disordercommonly affecting body folds. It can significantly impair quality of life due to the physical, psychological, and socialturmoil experienced by patients. Treatment remains a challenge.Limited data on the HS patient experience, such as self-treatment exists. Methods This w...
Article
Full-text available
Dupilumab is the only biologic therapy currently approved in Europe and the United States for severe atopic dermatitis in patients 6 years of age or older. Off-label use is rationalized in younger children with severe atopic dermatitis. Decisions about vaccination for children on dupilumab are complex and depend on both the child’s current treatmen...
Article
Full-text available
Lymphocytoma cutis reflects an exaggerated local immunologic reaction to a stimulus presenting on the head, neck, or upper extremities as a firm 1–3 cm erythematous and/or violaceous plaque or nodule. However, lymphocytoma cutis may be difficult to treat due to the variety of causative agents and the lack of reported successful treatments and outco...
Article
Full-text available
Introduction: An estimated 2-4% of Western populations are thought to have psoriasis, with a regional incidence ranging from 0.09% to 11.43%. Variance in estimates is a result of differences in study populations, methodology, regional differences, and definitions of disease. Reliable prevalence estimates of plaque psoriasis are challenging to esta...
Article
Full-text available
Idiopathic chilblains is a cold-induced inflammatory condition that causes significant morbidity. When preventative measures alone are inadequate, oral nifedipine is generally recommended as first-line pharmacologic therapy. Given the natural course of this spontaneously remitting/relapsing condition, controls are needed to critically appraise stud...
Article
Coronavirus disease 2019 (COVID-19) is caused by SARS-CoV-2, a novel RNA virus that was declared a global pandemic on 11 March 2020. The efficiency of infection with SARS-CoV-2 is reflected by its rapid global spread. The SARS-CoV-2 pandemic has implications for patients with inflammatory skin diseases on systemic immunotherapy who may be at increa...
Article
Full-text available
Background Hidradenitis suppurativa (HS) is associated with comorbidities that contribute to poor health, impaired life quality, and mortality risk. Objective To provide evidence-based screening recommendations for comorbidities linked to HS. Methods Systematic reviews were performed to summarize evidence on prevalence and incidence of 30 comorbi...
Article
Full-text available
Immune-mediated diseases and immunotherapeutics can negatively impact normal immune functioning and consequently vaccine safety and response. The COVID-19 pandemic has incited research aimed at developing a novel SARS-CoV-2 vaccine. As SARS-CoV-2 vaccines are developed and made available, the assessment of anticipated safety and efficacy in patient...
Article
Full-text available
Background: Schizophrenia is a debilitating neuropsychiatric condition that affects 0.5% of the North American population. Skin disease in schizophrenia has not been well described. Identifying skin diseases that are commonly comorbid with schizophrenia may help clinicians address the burden of skin disease in patients with schizophrenia. Summary...
Article
Full-text available
Pyoderma gangrenosum is a challenging disease to manage, due in part to the lack of approved treatment therapies. Recently, the emergence of biologic agents has expanded treatment options, with tumour necrosis factor alpha inhibitors being the best supported in the literature. In our report, we present a 50-year-old female with pyoderma gangrenosum...
Article
Background: Delusional infestation (DI) is a rare delusional disorder in which individuals have a false belief that they are infested with bugs, parasites, or insects, despite the lack of medical evidence that such an infestation exists. Data on the effectiveness of antipsychotics for DI are limited. Methods: We conducted a systematic review usi...
Article
Full-text available
Recommendations were made recently to limit or stop the use of oral and systemic immunotherapies for skin diseases due to potential risks to the patients during the current severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) COVID‐19 pandemic. Herein, we attempt to identify potentially safe immunotherapies that may be used in the treatment...
Article
Background Surgical excision is considered standard treatment for nodular basal cell carcinoma (nBCC). However, patients who reject or are unsuited for surgery may benefit from imiquimod (IMQ) 5% cream as an alternative treatment. Objectives The objective of this study was to conduct a systematic review on the efficacy and safety of IMQ for the tr...
Article
Full-text available
Background Indoor tanning (IT) in fitness facilities encourages a misleading positive relationship between tanning and health. While IT in Canadian fitness facilities has been studied, American literature regarding this topic is lacking. Objectives The objective of this study is to evaluate availability, cost, reported risks, and adherence to legi...
Article
Background Dermatological conditions are commonly seen in the emergency department and inpatient wards. The ability to access dermatology on-call services improves the accuracy of diagnosis and management of common and sometimes life-threatening conditions. Limitations of dermatologist availability led to the suspension of the dermatology on-call s...
Article
As part of an in-depth review of the specialty for the Royal College of Physicians and Surgeons of Canada (RCPSC), the Dermatology Working Group (DWG) was tasked with leading a comprehensive and objective analysis of the current state of Dermatology practice and training patterns in Canada. Preliminary research for the report was conducted in 3 are...
Article
Background and objective East Asians exposed to the urate-lowering drug allopurinol have a predilection for severe cutaneous drug reactions such as drug-induced hypersensitivity syndrome or drug reaction with eosinophilia and systemic symptoms (DRESS) and Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN). Screening is recommended in pat...
Article
Full-text available
The prevalence of tattoos is increasing and as such every physician must be aware of the potential adverse events associated with tattooing. Here we present a 36-year-old man with a recent history of skin-coloured papules appearing suddenly in a 20-year-old tattoo on the right forearm. Biopsy and histologic examination confirmed a diagnosis of verr...
Article
The specialty of dermatology is constantly changing to meet the medical needs of our society. The discipline is in flux because of a variety of factors such as growing population needs, technological advancements, fiscal restraint, and demographic changes. As part of an in-depth review of the specialty, the Dermatology Working Group (DWG) for the R...
Article
Background:: Although a variety of medical and surgical interventions exist for the treatment of hidradenitis suppurativa (HS), it remains a challenging disease to manage because of its variable presentation and unpredictable clinical course. Apart from the combination of clindamycin and rifampin, the success of other combination therapies is larg...
Article
Full-text available
Background:: Atopic dermatitis (AD) is a chronic, relapsing, and remitting inflammatory skin disease with complex pathophysiology, primarily driven by type 2 inflammation. Existing guidelines often do not reflect all current therapeutic options and guidance on the practical management of patients with AD is lacking. Objectives:: To develop pract...
Article
Full-text available
This document is a concise, current, and practical guide for dermatologists and other health care providers managing adult patients with moderate-to-severe atopic dermatitis (AD). The recommendations made here are based on a consensus of specialists with extensive experience managing patients with AD. Topics reviewed in this publication include AD...
Article
Full-text available
Atopic dermatitis (AD) is a chronic, relapsing, and remitting inflammatory skin disease whose onset typically occurs early in life. AD pathophysiology includes genetic, immune, and environmental factors contributing to chronic inflammation. A rapidly evolving understanding of the pathogenesis of AD has led to the development of several treatment op...
Article
There is a growing interest in the use of medical cannabis for a variety of dermatologic conditions. Despite the lack of evidence to validate the effectiveness and safety of marijuana, it is approved to treat a variety of dermatologic conditions in the United States. Furthermore, medical cannabis dispensaries have been making unsubstantiated claims...
Article
Background: Stevens-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN) are mucocutaneous hypersensitivity reactions, usually to drugs or their metabolites. TEN is the most severe involving greater than 30% of the total body surface area (TBSA). Management of these patients usually benefits from a large multidisciplinary team for both woun...
Article
Background: Atopy is a genetic predisposition to the development of allergic reactions and the increased production of immunoglobulin E (IgE) upon exposure to environmental antigens. Clinical manifestations of atopy include asthma, atopic dermatitis (AD), and allergic rhinoconjunctivitis (ARC). Objective: To determine if cutaneous delayed hypers...
Article
Cannabis (Cannabis sativa/indica), also known as marijuana, has been used for medicinal and recreational purposes for millennia. There has been a recent trend to legalize the use of cannabis, as illustrated by the recent legalization votes in numerous states in the United States and legislation in Canada to allow recreational cannabis use. With thi...
Article
The Symposium on Hidradenitis Suppurativa Advances (SHSA) took place on 22-23 October 2016 at Women's College Hospital in Toronto, Canada. This symposium was a joint meeting of the Canadian Hidradenitis Suppurativa Foundation (CHSF), and the Hidradenitis Suppurativa Foundation (HSF Inc.) founded in USA. The purpose of this meeting was to gather wel...
Article
Background: Hidradenitis suppurativa (HS) is a disease characterized by the development of painful, deep-seeded nodules and abscesses. Treatment guidelines include a combination of lifestyle, surgical, and medical interventions. Isotretinoin has not been included in the treatment guidelines due to the limited number of studies and conflicting repo...
Article
Aim: To develop a standardized practical screening tool for rheumatologists to assess for underlying dermatological manifestations of rheumatic conditions. Methods: A relevant screening tool was developed by consensus between dermatology and rheumatology authors. Patients visiting the general rheumatology clinic for routine care were systematica...
Article
Psoriasis is a common chronic inflammatory skin disease that manifests as scaly erythematous plaques as a consequence of keratinocyte hyperproliferation and inflammation. It is commonly associated with diabetes, obesity, and the metabolic syndrome. While there are numerous approved treatment options available, they have limitations including availa...
Article
Background: Ultraviolet (UV) radiation is a human carcinogen and is associated with the development of skin cancer. The promotion of indoor tanning (IT) at fitness centres is of particular concern as it reinforces the idea that a tan is associated with health and fitness. The purpose of this study was to investigate the prevalence of IT in fitness...
Article
Background: Liquid nitrogen cryotherapy is a commonly used technique to treat a wide variety of dermatologic conditions including actinic keratoses, non-melanoma skin cancers, verrucae, and seborrheic keratoses. The risks associated with liquid nitrogen cryotherapy are important to know and discuss with patients prior to treatment. Objective: We...
Article
Full-text available
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5135541/
Article
Importance: Drug-induced hypersensitivity syndrome (DIHS), also known as drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome, is a potentially life-threatening reaction to medications with a mortality rate up to 10%. Standard therapy involves the use of systemic corticosteroids with tapering doses extending up to 9 months after...
Article
Background: Stevens-Johnson syndrome and toxic epidermal necrolysis are severe mucocutaneous adverse drug reactions characterized by extensive epidermal detachment. The mortality rates have been reported to vary between 1-5% for Stevens Johnson syndrome and 25-35% for patients with toxic epidermal necrolysis. Studies have shown that early recognit...
Article
Tophaceous gout is the nonarticular deposition of monosodium urate resulting from a disorder in purine metabolism that causes an elevation of serum uric acid. Cutaneous variants of tophaceous gout include papular, nodular, ulcerative, and pustular forms. We present a case of a 67-year-old man who presented with multiple cutaneous creamy white papul...
Article
Pulmonary embolus (PE) and deep vein thrombosis (DVT) are manifestations of venous thromboembolism (VTE). Presence of autoimmune disease is a risk factor for the development of VTE. Autoimmune diseases with mucocutaneous involvement, such as systemic lupus erythematosus (SLE), dermatomyositis (DM), or Behçet syndrome, are strongly associated with V...
Article
Background: Trichodysplasia spinulosa (TS) is a rare, striking, folliculocentric papular eruption seen exclusively in immunosuppressed patients. The eruption can be disfiguring, associated with leonine faces and alopecia. TS is caused by a polyomavirus, identified as trichodysplasia spinulosa polyomavirus (TSPyV). Few reports exist in the literatu...
Article
Background: Bullous pemphigoid (BP) is an autoimmune polymorphic skin disease characterized by erythematous papules and plaques and tense bullae. A skin biopsy for direct immunofluorescence (DIF) is used to detect autoantibodies and complement proteins. Objective: We sought to determine which location would provide the highest probability of obt...
Article
A 48-year-old woman presented with traumatic injury secondary to removal of pubic hair using hot wax. Her medical history included long-standing type 1 diabetes mellitus, complicated by retinopathy, nephropathy and neuropathy. Because of diabetic complications, she had required a renal transplant five years before presentation and a pancreatic tran...
Article
Systemic lupus erythematosus (SLE) is an autoimmune disease that is characterized by the development of autoantibodies and immunologic attack of different organ systems, including the skin. This review aims to provide an overview of some of the pathogenic processes that may be important in the development of SLE, specifically cutaneous lupus erythe...
Article
Background: Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are mucocutaneous reactions, typically to medications, that are associated with a high patient mortality. Controversy exists over which systemic treatments decrease mortality associated with SJS/TEN. Objective: In this study we sought to determine whether intravenous...
Article
Importance Biochemical markers of disease allow clinicians to monitor disease severity, progression, and response to treatment. C-reactive protein and erythrocyte sedimentation rate are commonly used biochemical markers of inflammatory disease. We present 2 cases that indicate that D-dimer levels may be useful as a potential biochemical marker of...
Article
Parabens are preservatives used in a variety of personal care, cosmetic, pharmaceutical and food products. Studies have confirmed the ubiquitous presence of parabens, with levels detected in wastewater, rivers, soil and house dust. Parabens have also been detected in human tissues and bodily fluids, but it is the discovery of these chemical compoun...
Article
Full-text available
Stomatin-like protein 2 (SLP-2) is a member of the stomatin-prohibitin-flotillin-HflC/K (SPFH) superfamily. Recent evidence indicates that SLP-2 is involved in the organization of cardiolipin-enriched microdomains in mitochondrial membranes and the regulation of mitochondrial biogenesis and function. In T cells, this role translates into enhanced T...
Data
Localization of SLP-2 during IS formation. Antigen presenting cells (APCs) were incubated overnight with SEE (1 µg/ml), washed, resuspended in medium, and incubated on polylysine-coated glass bottom microwell dishes for 10 minutes to allow cells to adhere. SLP-2-gfp-expressing Jurkat T cells were added to the APCs preincubated with SEE on the polyl...
Data
Stability of SLP-2 clusters during T cell activation. Jurkat T cells stably expressing SLP-2-gfp were incubated on polylysine-coated glass bottom microwell dishes for 10 minutes to allow cells to adhere. Adherent Jurkat T cells were then stimulated with OKT3 (1 µg/ml) for 15 minutes and then placed under confocal microscope. Forty images were acqui...
Data
SLP-2 clusters are not static in non-stimulated T cells. Jurkat T cells stably expressing SLP-2-gfp were incubated on polylysine-coated glass bottom microwell dishes for 10 minutes to allow cells to adhere. Adherent, SLP-2-gfp expressing Jurkat T cells were then placed under confocal microscope. Forty images were acquired over a 375 seconds, with t...
Article
Full-text available
Stomatin-like protein 2 (SLP-2) is a widely expressed mitochondrial inner membrane protein of unknown function. Here we show that human SLP-2 interacts with prohibitin-1 and -2 and binds to the mitochondrial membrane phospholipid cardiolipin. Upregulation of SLP-2 expression increases cardiolipin content and the formation of metabolically active mi...
Article
Full-text available
T cell activation through the Ag receptor (TCR) requires sustained signaling from signalosomes within lipid raft microdomains in the plasma membrane. In a proteomic analysis of lipid rafts from human T cells, we identified stomatin-like protein (SLP)-2 as a candidate molecule involved in T cell activation through the Ag receptor. In this study, we...
Article
RpoS is a major regulator of genes required for adaptation to stationary phase in E. coli. However, the exponential phase expression of some genes is affected by rpoS mutation, suggesting RpoS may also have an important physiological role in growing cells. To test this hypothesis, we examined the regulatory role of RpoS in exponential phase using b...
Article
Full-text available
T cell activation through the antigen receptor (TCR) requires sustained signalling from microclusters in the peripheral region of the immunological synapse (IS). The bioenergetics of such prolonged signaling have been linked to the redistribution of mitochondria to the IS. Here, we report that stomatin-like protein-2 (SLP-2) plays an important role...
Article
Full-text available
The interaction between transmembrane proteins, lipids, and cytoskeletal components provides a framework for the compartmentalization of the cell surface. Intense research has focused on lipid rafts, the cholesterol-enriched membrane microdomains containing many signalling molecules. However, recent advances in cellular and molecular imaging have c...
Article
Within the paradigm of the two-signal model of lymphocyte activation, the interest in costimulation has witnessed a remarkable emergence in the past few years with the discovery of a large array of molecules that can serve this role, including some with an inhibitory function. Interest has been further enhanced by the realization of these molecules...
Article
Full-text available
Arginine biosynthesis in Escherichia coli is elevated in response to nutrient limitation, stress or arginine restriction. Though control of the pathway in response to arginine limitation is largely modulated by the ArgR repressor, other factors may be involved in increased stationary phase and stress expression. In this study, we report that expres...
Article
Full-text available
CTLA-4 is an activation-induced, homodimeric inhibitory receptor in T cells. Recent crystallographic reports have suggested that it may form lattice-like arrays on the cell surface upon binding B7.1/B7.2 (CD80, CD86) molecules. To test the biological relevance of these CTLA-4-B7 lattices, we introduced a C122A point mutation in human CTLA-4, becaus...
Article
Full-text available
Lipopolysaccharide (LPS) is a major component of the outer membrane of Gram-negative bacteria. As such, it signals monocytes, macrophages and neutrophils to up-regulate phagocytic functions and to release pro-inflammatory cytokines. Despite the established role of CD14 as the main LPS receptor, the precise nature of the LPS signalling complex and i...
Article
Full-text available
RpoS is a conserved alternative sigma factor that regulates the expression of many stress response genes in Escherichia coli. The RpoS regulon is large but has not yet been completely characterized. In this study, we report the identification of over 100 RpoS-dependent fusions in a genetic screen based on the differential expression of an operon-la...
Article
The alternative sigma factor RpoS controls the expression of many stationary-phase genes in Escherichia coli and other bacteria. Though the RpoS regulon is a large, conserved system that is critical for adaptation to nutrient deprivation and other stresses, it remains incompletely characterized. In this study, we have used oligonucleotide arrays to...