Urticarial lesions: if not urticaria, what else? The differential diagnosis of urticaria: part I. Cutaneous diseases

Urticaria

The relevance of the disease is due to its prevalence ― for acute urticaria up to 20% with predominance in the paediatric population, for chronic spontaneous urticaria up to 0.5–5% of the population. The course of the disease is characterised by unpredictability of prognosis of duration, effectiveness of standard therapy, serious impact on the quality of life of the patient, his relatives, the burden on health authorities. The lack of accurate understanding of the mechanisms of disease development, a wide range of pathogenetic treatment complicates the possibility of rapid achievement of drug remission. The clinical Recommendations contain up-to-date information on epidemiology, pathogenesis, clinical picture, differential diagnosis, possibilities of examination and stage treatment, including immunobiological therapy. The procedure of medical care, prophylaxis and dispensary observation, criteria for assessing the quality of patient management and supporting material, including questionnaires to assess the severity of the condition and the effectiveness of treatment are outlined. Clinical recommendations on urticaria are intended for practicing physicians of all specialities, students, teachers of medical schools, residents, postgraduates and researchers.

Modern Approaches to the Management of Patients with Urticaria

The Union of Pediatricians of Russia together with the Russian Association of Allergologists and Clinical Immunologists and the Russian Society of Dermatovenerologists and Cosmetologists have developed new clinical guidelines for the urticaria in adults and children. Urticaria is a common disease; its various clinical variants are diagnosed in 15–25% of people in the global population, and a quarter of all cases belongs to chronic urticaria. The prevalence of acute urticaria is 20%, and 2.1–6.7% in child population, whereas acute urticaria is more common in children than in adults. The prevalence of chronic urticaria in adults in the general population is 0.7 and 1.4%, and 1.1% in children under 15 years of age, according to the systematic review and meta-analysis, respectively. This article covers features of epidemiology, etiology, and pathogenesis of the disease with particular focus on differential diagnostic search. Guidelines on treatment and step-by-step therapy scheme (both based on principles of evidencebased medicine) for pediatric patients were presented. Clarification on the analysis of the therapy efficacy and the degree of disease activity was given.

Paraviral cutaneous manifestations associated to SARS-CoV-2 Omicron variant

BACKGROUND

The spreading of the SARS-CoV-2 Omicron variant is probably due to its increased transmissibility and ability to escape from neutralising antibodies. Cutaneous manifestations have been reported after infection with the Omicron strain, consisting mainly of generalised urticarial eruption and prickly heat rash, also known as miliaria, that can persist for several days. Here the impact of Omicron SARS-CoV-2 on skin was investigated.

METHODS

The case series of 10 patients with SARS-CoV-2 Omicron variant-related cutaneous manifestations were described; moreover, skin derived cells were challenged in vitro with SARS-CoV-2 Omicron variant.

RESULTS

The main clinical cutaneous features observed were urticarial lesions lasting more than 24 h, mainly involving the trunk and sometimes extending to the extremities, and miliaria presenting with clusters of small sweat-filled vesicles, sometimes surrounded by slight erythema. HaCaT keratinocytes, BJ fibroblast cell lines and outer root sheath (ORS) keratinocytes were not susceptible to SARS-CoV-2 Omicron variant infection; they also did not present any evident cytopathic effect or modification of cells viability.

CONCLUSION

Our findings suggests that, despite the high number of nucleotide mutations in the spike protein of SARS-CoV-2 Omicron variant, responsible to the higher transmissibility of this virus, and the increased reports of cutaneous manifestation in COVID-19 affected patients, the virus is not able to directly infect and damage the keratinocytes and fibroblasts, thus suggesting an indirect virus-induced activation of the immune system as the major pathogenetic driver.

RNF213-associated urticarial lesions with hypercytokinemia

BACKGROUND

Urticarial lesions are observed in both cutaneous and systemic disorders. Familial forms of urticarial syndromes are rare and can be encountered in systemic autoinflammatory diseases.

OBJECTIVE

We sought to investigate a large family with dominantly inherited chronic urticarial lesions associated with hypercytokinemia.

METHODS

We performed a genetic linkage analysis in 14 patients from a 5-generation family, as well as whole-exome sequencing, cytokine profiling, and transcriptomic analyses on samples from 2 patients. The identified candidate protein was studied after in vitro expression of the corresponding normal and mutated recombinant proteins. An unsupervised proteomic approach was used to unveil the associated protein network.

RESULTS

The disease phenotype of the most affected family members is characterized by chronic urticarial flares associated with extremely high plasma levels of proinflammatory (IL-1β, IL-6, and TNF-α) and anti-inflammatory (IL-10 and IL-1 receptor antagonist [IL-1RA]) cytokines, with no secondary organ dysfunction, no susceptibility to infections, no fever, and normal C-reactive protein levels. Monocyte transcriptomic analyses identified an immunotolerant profile in the most affected patient. The affected family members carried a loss-of-function mutation in RNF213 that encodes mysterin, a protein with a poorly known physiologic role. We identified the deubiquitinase CYLD, a major regulator of inflammation, as an RNF213 partner and showed that CYLD expression is inhibited by wild-type but not mutant RNF213.

CONCLUSION

We identified a new entity characterized by chronic urticarial lesions associated with a clinically blunted hypercytokinemia. This disease, which is due to loss of function of RNF213, reveals mysterin's key role in the complex molecular network of innate immunity.

Annular urticarial lesions

Annular urticarial configurations are often associated with acute and chronic urticaria. Such lesions may be short-lived, migratory, transient, pruritic, and resolving with no residual evidence, making the diagnosis of urticaria an obvious one. Annular urticarial lesions can be the presenting signs of various cutaneous and systemic diseases. The differentiation of urticarial lesions may be made by considering the duration of an individual lesion longer than 24 hours, with burning and pain sensation in the lesions or lack of pruritus; skin marks such as postinflammatory pigmentation or purpura after resolution of the lesions; associated scaling or vehiculation in the lesions; systemic symptoms such as arthralgia, fever or fatigue; and several abnormal laboratory findings. The main differential diagnoses of annular urticarial lesions include urticarial vasculitis, autoinflammatory syndromes, hypersensitivity reactions, and connective tissue diseases.

Urticarial vasculitis: Clinical and laboratory findings with a particular emphasis on differential diagnosis

Urticarial vasculitis (UV) is a rare cutaneous vasculitis of small vessels characterized by recurrent episodes of wheal-like lesions that tend to last more than 24 hours, healing with a residual ecchymotic postinflammatory hyperpigmentation. The histopathologic pattern of UV is that of leukocytoclastic vasculitis, consisting of fibrinoid necrosis of dermal vessels' walls and neutrophil-rich perivascular inflammatory infiltrates. Although its etiopahogenesis remains still undefined, UV is now regarded as an immune complex-driven disease with activation of the complement cascade, leading to exaggerated production of anaphylatoxins that are responsible for neutrophil recruitment and activation. This condition can be categorized into 2 main entities according to serum complement levels: normocomplementemic UV and hypocomplementemic UV, the latter being associated with circulating anti-C1q autoantibodies and possible extracutaneous manifestations. Systemic multiorgan involvement may be seen particularly in syndromic hypocomplementemic UV, also known as McDuffie syndrome. This review summarizes the clinicopathological and laboratory features as well as the underlying pathophysiological mechanisms of UV. A focus on its main differential diagnoses is provided, that is, chronic spontaneous urticaria, bullous pemphigoid, IgA (Henoch-Schönlein purpura) and IgM/IgG immune complex vasculitis, lupus erythematous tumidus, Wells syndrome, erythema multiforme, cutaneous mastocytosis, cryopyrin-associated periodic syndromes, and coronavirus disease 2019-associated and anti-severe acute respiratory syndrome coronavirus 2-vaccine-associated urticarial eruptions.

The Diagnostic Workup in Chronic Spontaneous Urticaria-What to Test and Why

BACKGROUND

In chronic spontaneous urticaria (CSU), the guidelines recommend very limited diagnostic procedures during the routine workup, although additional investigations might be indicated in some patients with CSU. For physicians treating patients with CSU, it is often difficult to decide which diagnostic tests are useful.

OBJECTIVE

To provide recommendations on what diagnostic tests should be performed on which patients with CSU.

METHODS

We performed an extensive literature search on the respective topics and identified relevant questions that should prompt diagnostic procedures based on the published evidence and expert consensus among all authors.

RESULTS

We provide questions, diagnostic testing, where appropriate, and recommendation that should be included when assessing the history of a patient with CSU, to explore and rule out differential diagnoses, to assess patients for underlying causes and modifying conditions, to explore patients for comorbid diseases and consequences of having CSU, and to assess patients for CSU components that can help to predict their disease course and response to treatment.

CONCLUSIONS

Here, we provide physicians treating patients with CSU with information about which clues should lead to which tests and why.

Histopathology of chronic spontaneous urticaria with occasional bruising lesions is not significantly different from urticaria with typical wheals

BACKGROUND

Chronic spontaneous urticaria (CSU) may occasionally exhibit long-lasting lesions with bruising, usually considered a hallmark of urticarial vasculitis (UV). Histopathology of these chronic urticarial lesions has not been extensively studied.

METHODS

Skin biopsies from patients with anti-H1 resistant CSU were evaluated for several parameters (edema, location, intensity, and cell composition of the inflammatory infiltrate, and abnormalities in the blood vessels).

RESULTS

We studied 45 patients (37 female/8 male, mean age 49.3 years) with CSU, 60% of whom with occasional bruising lesions and 3 patients with hypocomplementemic UV. Histopathology in CSU showed mainly perivascular and interstitial inflammatory infiltrate (91.1%), including eosinophils (80%), neutrophils (77.8%), and lymphocytes (71.1%), vasodilatation (88.9%), intravascular neutrophils (95.6%), dermal edema (51.1%), swelling of endothelial cells (51.1%), and minor and rare fibrinoid necrosis and karyorrhexis (6.7%). Significant karyorrhexis and frank fibrinoid necrosis were observed, respectively, in two and three cases of UV. In patients with occasional bruising, mast cells occurred in fewer cases whereas eosinophils were more frequent, but no statistically significant difference was found for other parameters.

CONCLUSIONS

Histopathological findings were not significantly different between CSU with or without bruising lesions. Bruising may be associated with more severe forms of CSU with no histopathological signature, although UV cannot be completely excluded based on histopathology.

Skin Biopsy in Chronic Urticaria: When and Where and What to Look for?

Chronic urticaria is a relatively common condition in dermatology and is usually diagnosed on clinical grounds. Skin biopsy, however, may be indicated in certain cases to confirm diagnosis and rule out other conditions that can cause hive-like rashes. We review histopathologic findings seen in both chronic urticaria and other entities in the differential diagnosis. We then propose an algorithm of indications for skin biopsy in patients with hive-like rashes and suggest possible diagnoses based on the histopathologic findings.

Review of adverse cutaneous reactions of pharmacologic interventions for COVID-19: A guide for the dermatologist

The new coronavirus, severe acute respiratory syndrome coronavirus 2, is associated with a wide variety of cutaneous manifestations. Although new skin manifestations caused by COVID-19 are continuously being described, other cutaneous entities should also be considered in the differential diagnosis, including adverse cutaneous reactions to drugs used in the treatment of COVID-19 infections. The aim of this review is to provide dermatologists with an overview of the cutaneous adverse effects associated with the most frequently prescribed drugs in patients with COVID-19. The skin reactions of antimalarials (chloroquine and hydroxychloroquine), antivirals (lopinavir/ritonavir, ribavirin with or without interferon, oseltamivir, remdesivir, favipiravir, and darunavir), and treatments for complications (imatinib, tocilizumab, anakinra, immunoglobulins, corticosteroids, colchicine and low molecular weight heparins) are analyzed. Information regarding possible skin reactions, their frequency, management, and key points for differential diagnosis are presented.

Urticaria and angioedema as a prodromal cutaneous manifestation of SARS-CoV-2 (COVID-19) infection

This is a case of a patient who presented with an urticarial rash 48 hours before developing symptoms of fever and a continuous cough. She subsequently developed angioedema of her lips and hands before testing positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Urticarial rashes occurring 48 hours before other symptoms of COVID-19 infection have been documented. This case demonstrates the importance of heightened awareness that not all urticarial rashes represent spontaneous urticaria and as a consequence, this may result in misdiagnosis and ultimately delayed diagnosis. This is the first reported case in the literature of urticaria with angioedema as a prodromal phenomenon of COVID-19.

Urticaria: recommendations from the Italian Society of Allergology, Asthma and Clinical Immunology and the Italian Society of Allergological, Occupational and Environmental Dermatology

BACKGROUND

Urticaria is a disorder affecting skin and mucosal tissues characterized by the occurrence of wheals, angioedema or both, the latter defining the urticaria-angioedema syndrome. It is estimated that 12-22% of the general population has suffered at least one subtype of urticaria during life, but only a small percentage (estimated at 7.6-16%) has acute urticaria, because it is usually self-limited and resolves spontaneously without requiring medical attention. This makes likely that its incidence is underestimated. The epidemiological data currently available on chronic urticaria in many cases are deeply discordant and not univocal, but a recent Italian study, based on the consultation of a national registry, reports a prevalence of chronic spontaneous urticaria of 0.02% to 0.4% and an incidence of 0.1-1.5 cases/1000 inhabitants/year.

METHODS

We reviewed the recent international guidelines about urticaria and we described a methodologic approach based on classification, pathophysiology, impact on quality of life, diagnosis and prognosis, differential diagnosis and management of all the types of urticaria.

CONCLUSIONS

The aim of the present document from the Italian Society of Allergology, Asthma and Clinical Immunology (SIAAIC) and the Italian Society of Allergological, Occupational and Environmental Dermatology (SIDAPA) is to provide updated information to all physicians involved in diagnosis and management of urticaria and angioedema.

Polymorphic eruption of pregnancy in Mexico

BACKGROUND

Currently, the exact incidence of Polymorphic Eruption of Pregnancy (PEP) in the Mexican population is unknown. PEP tends to manifest in the abdomen, primarily in the stretch marks caused by distension. It is characterized by severely pruritic urticarial-like papules that converge in plaques, extending to the buttocks and proximal thighs. Our study determined its incidence, along with other common dermatoses in pregnancy.

METHODS

Patients between 14 and 45 years of age were evaluated. In each patient, a complete medical history and physical examination was performed with emphasis on skin and adnexa. Patients were followed until the end of their pregnancy.

RESULTS

A total of 217 women were included. PEP was identified in three patients (1.38%), all primigravida, with single fetus pregnancy, and all concluded their pregnancy by vaginal delivery. The neonates were 2 females and 1 male. No other gestational pathologies were identified.

CONCLUSIONS

We identified a higher incidence of PEP than reported, without association to complications or need for medical management. There may be an association between high maternal weight and the presence of PEP, however a larger sample is needed.

Pediatric Erythema Multiforme in the Emergency Department: More Than "Just a Rash"

OBJECTIVES

Erythema multiforme (EM) is characterized by symmetrical acrally distributed target lesions; however, other conditions can mimic the clinical features of EM. Although it is typically self-limiting, alternative diagnoses may be life-threatening and require immediate identification and treatment. This study aimed to investigate the clinical spectrum and accuracy of diagnosis of pediatric EM in the emergency department (ED).

METHODS

A retrospective, descriptive study of all pediatric patients with an ED information system diagnosis of EM at 2 EDs in Southeast Queensland between January 2010 and July 2013. Cases were evaluated using previously established EM classification criteria.

RESULTS

Seventy patients (34 males and 36 females) with a diagnosis of EM were identified. From 57 cases where a diagnosis could be established, 9 cases fulfilled the classification criteria for EM. No patients had mucosal involvement, and therefore, all 9 cases were classified as EM minor, with the majority (89%) attributed to viral infection. Of the 48 cases that did not fit the criteria, the most common condition misdiagnosed as EM was urticaria multiforme (n = 20).

CONCLUSIONS

In the ED setting, EM in children is frequently misdiagnosed. Greater awareness of diagnostic factors for EM may improve diagnostic accuracy. Teledermatology and incentives to include clinical pictures in the (electronic) medical record may be useful adjuncts for patients with suspected EM and other dermatological conditions.

Anaphylaxis and urticaria

Anaphylaxis and urticaria are common presenting allergic complaints. Affecting up to 2% of the population, anaphylaxis is a serious, life-threatening allergic reaction. Although not life-threatening, urticaria is a rash of transient, erythematous, pruritic wheals that can be bothersome and affects up to 25% of the population. All cases of anaphylaxis warrant thorough clinical evaluation by the allergist-immunologist, although most cases of urticaria are self-limited and do not require specialist referral. This article offers an overview of our current knowledge on the epidemiology, pathogenesis, triggers, diagnosis, and treatment of anaphylaxis and urticaria.

Urticaria

Urticaria is a very common skin disease which was already described in the ancient world. Questions still remain about its pathogenesis and management remain open. Compared to other common skin diseases, the published evidence is rather low. The clinical symptoms with pruritic transient wheals and/or angioedema are caused by mediators (particularly histamine) released by activated mast cells and basophils. The mechanism of target cell activation has not been clarified in detail for most urticaria subtypes. Different urticaria subtypes should be distinguished. Spontaneous forms are more common than inducible forms. Chronic urticaria and urticaria in certain age groups (children, pregnancy) can be difficult to manage. Therefore, international consensus resulting in the regular update of urticaria guidelines can be very helpful. Currently, these updated guidelines include a three-step treatment algorithm for chronic spontaneous urticaria. Only the first step of this algorithm, second generation H1-antihistamine in standard dose, utilized approved drugs. However after omalizumab was established as a third line choice in the guideline algorithm, it has approved in many countries for chronic spontaneous urticaria without response to H1-antihistamines. The exact mechanism of action of omalizumab in urticaria has not been fully elucidated. Unrevealing this mechanism might result in a deeper understanding of urticaria pathogenesis and the development of further therapeutic strategies.

Platelet and other hemostatic characteristics in patients with chronic urticaria

Several publications have pointed out the importance of coagulation and fibrinolysis in the occurrence of chronic urticaria (CU), but only a few indicated the direct role of platelets. We assessed platelet aggregation and evaluated parameters of coagulation and fibrinolysis in patients with CU. Patients (n = 34) diagnosed as having CU and 36 healthy controls were enrolled. Platelet aggregation was assayed using an impedance aggregometer and adenosine diphosphate, arachidonic acid, thrombin receptor-activating peptide (TRAP), and ristocetin as agonists. In patients with CU, significantly decreased platelet aggregation to some agonists (ristocetin and TRAP) was observed. The D-dimer levels were elevated, mean platelet volume was decreased, but no alteration was observed in other coagulation assays. Elevated D-dimer levels indicated that coagulation and fibrinolysis are activated in the patients with CU. Evaluation of platelet function may contribute to identify the role of these cells in the pathogenesis of CU.

Cutaneous drug reactions in the pediatric population

Cutaneous adverse drug reactions (ADRs) constitute a major pediatric health problem frequently encountered in clinical practice, and represent a diagnostic challenge. Children are more susceptible than adults to errors in drug dosage because of their smaller body size; moreover, ADRs can mimic other skin diseases of children, especially viral exanthems. Most ADRs with cutaneous involvement are mild and resolve on withdrawal of the causative drug. The most common forms of cutaneous ADRs, maculopapular exanthems and urticarial reactions, have excellent outcomes. Less frequent but more severe reactions may incur a risk of mortality.

[Neutrophilic urticaria or urticaria with predominantly neutrophilic inflammatory infiltrate: study of its clinical and histopathologic characteristics and its possible association with rheumatic disease]

INTRODUCTION

Neutrophilic urticaria, described by Winkelmann in 1985, has yet to be completely defined and its clinical significance is poorly understood. Nevertheless, recent publications suggest that it could be a marker for rheumatic disease. The primary objective of this study was to compare the prevalence of rheumatic disease in 2 groups of patients with urticaria: those with conventional urticaria (non-neutrophilic inflammatory infiltrate) and those with neutrophilic urticaria.

MATERIAL AND METHODS

We retrospectively reviewed all biopsy samples taken from urticarial lesions in our hospital between January 1, 1999 and June 28, 2009. Urticaria was classified according to predefined morphologic and histopathologic patterns. We compared the clinical and histologic characteristics of neutrophilic urticaria with those of conventional urticarias in the 84 patients included.

RESULTS

Of the 84 patients, 57.1% had neutrophilic urticaria. We did not find significant differences between the percentages of patients with rheumatic disease between the neutrophilic and nonneutrophilic urticaria groups. In patients with acute urticaria, we found a significantly higher proportion of samples with histopathologic signs of neutrophilic urticaria as opposed to conventional histopathology. Patients with neutrophilic urticaria also had higher white blood cell counts.

CONCLUSIONS

The percentage of samples with neutrophilic urticaria in this series (57.1%) is higher than the percentages reported in the literature, possibly because we tended to biopsy recent lesions. We highlight that the presence of neutrophils in the biopsies of urticaria is a common finding and does not appear to be associated with other diseases.

An approach to the hospitalized patient with urticaria and fever

Urticaria is a common skin disorder with a long differential diagnosis. Most cases are readily treated symptomatically and have no systemic implications. However, a number of diseases and syndromes, including vasculitides, immunologic disorders, infectious diseases, hematologic diseases, and autoinflammatory syndromes, can present with urticaria and systemic symptoms, which may lead to hospitalization of the patient. These urticarial syndromes are important to recognize as they often have significant health implications. A comprehensive history and physical exam is important in distinguishing cases of simple urticaria from these syndromes. The presence of atypical wheals, systemic symptoms such as fever or arthralgia, and a lack of response to antihistamine therapy are important diagnostic clues that should prompt further workup.