Idiopathic cold urticaria: in vitro demonstration of histamine release upon challenge of skin biopsies

New insights into chronic inducible urticaria

PURPOSE OF REVIEW

Chronic inducible urticaria (CIndU) is a group of long-persisting and challenging to manage diseases, characterized by recurrent wheals and angioedema induced by definite triggers. In this review, we address recent findings on CIndU pathogenesis, diagnosis as well as its treatment, and we discuss novel potential targets that may lead to the development of more effective therapies for CIndU patients.

RECENT ADVANCES

Meaningful advances in the understanding of its pathogenesis have been reported in the last decades. Novel CIndU-specific patient-reported outcome measures enable a closer and better evaluation of patients. CIndU is a hard-to-treat disease that highly impairs quality of life (QoL) of affected patients. Provocation tests allow to diagnose CIndU subtypes. The only licensed and recommended treatment for CIndU are second generation non-sedating H1-antihistamines, which lack efficacy in many cases. Omalizumab off-label use has been assessed in all types of CIndU with overall good outcomes. Promising emerging therapies currently assessed in chronic spontaneous urticaria are paving the path for novel treatments for CIndU.

Cold Anaphylaxis in Children: Italian Case Series and Review of the Literature

Chronic urticaria (CU) is one of the most common skin disorders worldwide. Among the inducible subgroup of CU, cold urticaria (ColdU) can affect both children and adults and is the only type associated with the risk of anaphylaxis without cofactors. In the scientific literature, data about cold anaphylaxis (ColdA) are poor, especially at pediatric age, and little is known about risk factors associated with the onset of systemic reactions and about the criteria for prescribing adrenaline auto-injectors (AAIs) in these patients. We describe the clinical characteristics and management of a case series of 21 patients with a history of ColdA, and we compare them with the pediatric case reports and case series published so far. On the basis of the scientific literature and of our case series of patients, we suggest that AAI should be prescribed to all high-risk patients: those with urticaria caused by cold-water immersion, oropharyngeal reactions, and with a previous history of systemic symptoms or anaphylaxis.

Cold Urticaria Syndromes: Diagnosis and Management

Cold urticaria is a chronic condition causing episodic symptoms of cold-induced wheals or angioedema in response to direct or indirect exposure to cold temperatures. Whereas symptoms of cold urticaria are typically benign and self-limiting, severe systemic anaphylactic reactions are possible. Acquired, atypical, and hereditary forms have been described, each with variable triggers, symptoms, and responses to therapy. Clinical testing, including response to cold stimulation, helps define disease subtypes. More recently, monogenic disorders characterized by atypical forms of cold urticaria have been described. Here, we review the different forms of cold-induced urticaria and related syndromes and propose a diagnostic algorithm to aid clinicians in making a timely diagnosis for the appropriate management of these patients.

Remibrutinib inhibits hives effector cells stimulated by serum from chronic urticaria patients independently of FcεR1 expression level and omalizumab clinical response

BACKGROUND

Despite advances in the treatment of chronic urticaria, in a significant percentage of the patients symptoms are not fully controlled with conventional approaches. New strategies under development include blocking intracellular mediators of mast cell and basophil activation.

OBJECTIVE

We aim to investigate the effects of the Bruton's tyrosine kinase (BTK) inhibitor remibrutinib on human blood basophils and CD34+ -derived mast cells activation induced by serum obtained from chronic urticaria patients.

METHODS

Twenty-two patients with chronic spontaneous urticaria (mean age 52 years, 27% women) and 22 patients with chronic inducible urticaria (46 years, 27% women) were included in the study together with a sex-matched control group. Patients were classified as responders or non-responders to anti-IgE therapy on the basis of their clinical data, FcεR1a expression on blood basophils and total IgE levels. Changes on CD63 expression-as an activation marker-, were used to evaluate in vitro the response of basophils and mast cells to serum exposure and the inhibitory effects of remibrutinib.

RESULTS

Remibrutinib inhibits degranulation induced by IgE cross-linking in mast cells and basophils and also the activation triggered by factors present in the sera of spontaneous and inducible chronic urticaria patients. Patient's serum induces a greater degranulation of effector cells than controls. Activation of mast cells and basophils by patient sera and remibrutinib effects were not related to omalizumab responsiveness.

CONCLUSION

Remibrutinib inhibits activation of human basophils and mast cells induced in vitro by exposure to the serum of chronic urticaria patients independently of their response to omalizumab.

Inhibition of interleukin‐1 with rilonacept is not effective in cold urticaria—Results of a randomized, placebo‐controlled study

Background

Cold urticaria (ColdU) is characterized by pruritic wheals following exposure of the skin to cold. Many patients show insufficient response to antihistamines, the first line treatment. Based on the high efficacy of interleukin‐1(IL‐1)‐inhibition in cold‐induced urticarial autoinflammatory diseases, we assessed the effects of rilonacept, an IL‐1 inhibitor, in ColdU patients unresponsive to standard treatment.

Methods

In this randomized, double‐blind, placebo‐controlled two‐center study, we included 20 patients with ColdU. In the first part, patients received 320 mg rilonacept or placebo (1:1) followed by weekly doses of 160 mg rilonacept or placebo for 6 weeks. In the second part, all patients received weekly 160 mg or 320 mg rilonacept for 6 weeks, open‐label. The primary endpoint was change in critical temperature threshold (CTT). Secondary endpoints included changes in quality of life impairment (Dermatology Life Quality Index, DLQI), differences of inflammatory mediators upon cold provocation and safety assessment over the study period.

Results

Baseline mean CTTs were 20.2°C (placebo) and 17.3°C (rilonacept). Mean CTTs did not change significantly during the 6‐week double‐blind treatment (placebo – 0.45°C; rilonacept +0.89°C). IL‐6, IL‐18 and HSP‐70 blood levels showed interindividual variability without significant changes during hand cold water bath provocation in placebo‐ or rilonacept‐treated patients. In contrast, DLQI significantly improved in the rilonacept (mean DLQI reduction of 3.8; p = 0.002) but not in the placebo group (mean DLQI reduction of 0). Comparing baseline with the rilonacept open‐label treatment, there were no changes in CTTs or DLQI scores.

Conclusion

IL‐1 inhibition with rilonacept did not improve ColdU, but demonstrated a good safety profile.

Clinical Trial Registration

EudraCT number: 2012‐005726‐30. ClinicalTrials.gov identifier: NCT02171416.

Evidence for histamine release in chronic inducible urticaria – A systematic review

Background

Chronic inducible urticaria (CIndU) constitutes a group of nine different CIndUs in which pruritic wheals and/or angioedema occur after exposure to specific and definite triggers. Histamine released from activated and degranulating skin mast cells is held to play a key role in the pathogenesis of CIndU, but evidence to support this has, as of yet, not been reviewed systematically or in detail. We aim to characterize the role and relevance of histamine in CIndU.

Methods

We systematically searched 3 electronic databases (PubMed, Scopus, and Embase) for studies that reported increased serum or skin histamine concentration (direct evidence) or in vitro or ex vivo histamine release (indirect evidence) following trigger exposure.

Results

An initial total of 3,882 articles was narrowed down to 107 relevant studies of which 52 were in cold urticaria, 19 in cholinergic urticaria, 14 in heat urticaria, 10 in contact urticaria, 7 each in solar urticaria and vibratory angioedema, 4 each in symptomatic dermographism and aquagenic urticaria, and 3 in delayed pressure urticaria. The results of our review support that histamine has a key pathogenic role in the pathogenesis of all CIndUs, but it is not the sole mediator as evidenced by the often poor relationship between the level of histamine and severity of symptoms and the variable clinical efficacy of H1-antihistamines.

Conclusions

Histamine released from skin mast cells is a key driver of the development of signs and symptoms and a promising therapeutic target in CIndU.

Cold urticaria - What we know and what we do not know

Cold urticaria (ColdU) is a common form of chronic inducible urticaria characterized by the development of wheals, angioedema or both in response to cold exposure. Recent research and guideline updates have advanced our understanding and management of ColdU. Today, its pathophysiology is thought to involve the cold-induced formation of autoallergens and IgE to these autoallergens, which provoke a release of proinflammatory mediators from skin mast cells. The classification of ColdU includes typical and atypical subtypes. We know that cold-induced wheals usually develop on rewarming and resolve within an hour and that anaphylaxis can occur. The diagnosis relies on the patient's history and cold stimulation testing. Additional diagnostic work-up, including a search for underlying infections, should only be done if indicated by the patient's history. The management of ColdU includes cold avoidance, the regular use of nonsedating antihistamines and the off-label use of omalizumab. However, many questions regarding ColdU remain unanswered. Here, we review what is known about ColdU, and we present important unanswered questions on the epidemiology, underlying pathomechanisms, clinical heterogeneity and treatment outcomes. Our aim is to guide future efforts that will close these knowledge gaps and advance the management of ColdU.

Treatment of urticaria: a clinical and mechanistic approach

PURPOSE OF REVIEW

This manuscript describes the recommended therapy of chronic spontaneous urticaria based on our understanding of the pathogenesis of hive formation. Thus, the mechanism of action of each medication is elaborated in addition to a discussion of clinical utility.

RECENT FINDINGS

The main drugs are antihistamines, omalizumab, and cyclosporine with a success rate of 40-55, 65-80, and 70-80%, respectively. Used in sequence, over 90% of patients can be successfully treated. The addition of omalizumab represents a major advance because of its efficacy, easy utility, and favorable side-effect profile. The interaction with IgE eliminates any reaction with antigens to which it might be directed, down regulates IgE receptors on mast cells and basophils, and leads to down-regulation of mast cell functions with amelioration of hives.

SUMMARY

The use of antihistamines in high dosage (at least four times a day) is effective in close to half the patients with CSU. For antihistamine resistance, the use of omalizumab has revolutionized therapy of antihistamine-resistant cases because of its efficacy and excellent side-effect profile. If the response is insufficient, cyclosporine is the next choice. Patients should be monitored regarding any adverse effects on blood pressure or renal function. All these are far safer than extended use of corticosteroid.

Immunoglobulin E-Mediated Autoimmunity

The study of autoimmunity mediated by immunoglobulin E (IgE) autoantibodies, which may be termed autoallergy, is in its infancy. It is now recognized that systemic lupus erythematosus, bullous pemphigoid (BP), and chronic urticaria, both spontaneous and inducible, are most likely to be mediated, at least in part, by IgE autoantibodies. The situation in other conditions, such as autoimmune uveitis, rheumatoid arthritis, hyperthyroid Graves’ disease, autoimmune pancreatitis, and even asthma, is far less clear but evidence for autoallergy is accumulating. To be certain of an autoallergic mechanism, it is necessary to identify both IgE autoantibodies and their targets as has been done with the transmembrane protein BP180 and the intracellular protein BP230 in BP and IL-24 in chronic spontaneous urticaria. Also, IgE-targeted therapies, such as anti-IgE, must have been shown to be of benefit to patients as has been done with both of these conditions. This comprehensive review of the literature on IgE-mediated autoallergy focuses on three related questions. What do we know about the prevalence of IgE autoantibodies and their targets in different diseases? What do we know about the relevance of IgE autoantibodies in different diseases? What do we know about the cellular and molecular effects of IgE autoantibodies? In addition to providing answers to these questions, based on a broad review of the literature, we outline the current gaps of knowledge in our understanding of IgE autoantibodies and describe approaches to address them.

Omalizumab treatment in patients with chronic inducible urticaria: A systematic review of published evidence

BACKGROUND

Omalizumab, a recombinant anti-IgE antibody, effectively treats chronic spontaneous urticaria. Evidence is lacking in patients with chronic inducible urticarias (CIndUs), which are frequently H₁-antihistamine resistant.

OBJECTIVE

From the current published literature, we aimed to determine the strength of evidence for omalizumab efficacy and safety in the treatment of CIndUs.

METHODS

We performed a PubMed search to identify evidence on omalizumab use in the following 9 CIndU subtypes: symptomatic dermographism, cold urticaria, delayed-pressure urticaria, solar urticaria, heat urticaria, vibratory angioedema, cholinergic urticaria, contact urticaria, and aquagenic urticaria.

RESULTS

Forty-three trials, case studies, case reports, and analyses were identified. Our review indicates that omalizumab has substantial benefits in patients with various CIndUs. The evidence is strongest for symptomatic dermographism, cold urticaria, and solar urticaria. Little/no evidence was available on vibratory angioedema and aquagenic and contact urticaria. Our review supports rapid onset of action demonstrated through early symptom control in most cases, sometimes within 24 hours. Many patients gained complete/partial symptom relief and substantially improved quality of life. Adverse events were generally low, with omalizumab being well tolerated by most patients, including children.

CONCLUSIONS

A strong body of evidence supports the use of omalizumab in the treatment of patients with therapy-refractory CIndU. More data from randomized controlled studies are warranted.

Mast Cells Promote Seasonal White Adipose Beiging in Humans

Human subcutaneous (SC) white adipose tissue (WAT) increases the expression of beige adipocyte genes in the winter. Studies in rodents suggest that a number of immune mediators are important in the beiging response. We studied the seasonal beiging response in SC WAT from lean humans. We measured the gene expression of various immune cell markers and performed multivariate analysis of the gene expression data to identify genes that predict UCP1. Interleukin (IL)-4 and, unexpectedly, the mast cell marker CPA3 predicted UCP1 gene expression. Therefore, we investigated the effects of mast cells on UCP1 induction by adipocytes. TIB64 mast cells responded to cold by releasing histamine and IL-4, and this medium stimulated UCP1 expression and lipolysis by 3T3-L1 adipocytes. Pharmacological block of mast cell degranulation potently inhibited histamine release by mast cells and inhibited adipocyte UCP1 mRNA induction by conditioned medium (CM). Consistently, the histamine receptor antagonist chlorpheniramine potently inhibited adipocyte UCP1 mRNA induction by mast cell CM. Together, these data show that mast cells sense colder temperatures, release factors that promote UCP1 expression, and are an important immune cell type in the beiging response of WAT.

Mechanisms of action that contribute to efficacy of omalizumab in chronic spontaneous urticaria

The monoclonal anti-immunoglobulin E (IgE) antibody, omalizumab, was the first drug approved for use in patients with chronic idiopathic/spontaneous urticaria (CIU/CSU) who remain symptomatic despite H₁ -antihistamine treatment. Omalizumab binds to free IgE, which lowers free IgE levels and causes FcεRI receptors on basophils and mast cells to be downregulated. It has been shown to improve symptoms of CIU/CSU, but its mechanism of action is not currently understood. Potential mechanisms in CIU/CSU include reducing mast cell releasability, reversing basopenia and improving basophil IgE receptor function, reducing activity of IgG autoantibodies against FcεRI and IgE, reducing activity of IgE autoantibodies against an antigen or autoantigen that has yet to be definitively identified, reducing the activity of intrinsically 'abnormal' IgE, and decreasing in vitro coagulation abnormalities associated with disease activity. However, none of these theories alone or in combination fully account for the pattern of symptom improvement seen with omalizumab therapy, and therefore, no one mechanism is likely to be the definitive mechanism of action. Additional research is needed to further clarify the involvement of omalizumab in relieving symptoms associated with the complex, multifactorial pathogenesis of CIU/CSU.

Chronic spontaneous urticaria: etiology and pathogenesis

Urticaria affects individuals of all ages and is commonplace. Nearly 1 in 5 individuals will experience an episode of urticaria in their lifetime, while the chronic form of disease has an estimated annual prevalence of approximately 1% of the population. Given the similarity of chronic urticaria symptoms to those seen in patients suffering an allergic reaction, the condition often leads to a search for an external cause. In most cases, no external trigger factor is identified. At present several theories of pathogenesis exist, none of which is firmly established.

Mechanisms and potential therapeutic targets in allergic inflammation: recent insights

Deeper insight into pathogenetic pathways and into the biological effects of immunomodulatory agents will help to optimize or adopt therapeutic strategies for atopic disorders. In this article, we highlight selected findings of potential therapeutic relevance that emerged from recent mechanistic studies with focus on molecular and cellular aspects of allergic inflammation. Furthermore, the often complex mechanisms of action of pleiotropic immunomodulatory agents, such as glucocorticoids, vitamin D, or intravenous immunoglobulin (IVIG), are discussed, as their dissection might reveal targets for novel therapeutics or lead to a more rational use of these compounds. Besides reporting novel evidence, this article points to areas of current debate or uncertainty and aims at stimulating scientific discussion and experimental work.

Cold-induced urticaria: challenges in diagnosis and management

Cold-induced urticaria (CU) is a chronic physical urticaria that can be hard to diagnose and manage. Symptoms of CU can vary from mild localised urticaria, angio-oedema to anaphylaxis. CU may be induced by a wide range of cold triggers from aquatic activities to ingestions of cold substances. This exemplifies the importance of accurate diagnosis and management of patients with CU. We present three cases of CU that demonstrate the variability in triggers and clinical presentation.

Biologic agents in the treatment of urticaria

Numerous controlled studies as well as case reports have demonstrated that Omalizumab can be employed successfully in approximately 75 % of patients with chronic spontaneous urticaria, leading to a dramatic decrement in symptoms with very few side effects. No other drug currently available is comparable, and the success rate in patients resistant to antihistamines is no different. In the U.S., Phase I and Phase II trials are complete and we await the results of a Phase III multicenter study, with a view to eventual submission to the Food and Drug Administration in the U.S. and to comparable agencies abroad seeking approval for this indication. Omalizumab is currently marketed for the treatment of severe allergic asthma. Case reports suggest efficacy in difficult cases of physical urticaria, but no controlled trails have been done. Other agents require further evaluation for possible efficacy in the treatment of chronic spontaneous urticaria, including antibody to CD20, a B-lymphocyte cell surface marker, anti-TNFα, and anti-Interleukin 1. Thus far, targeting TNFα has been disappointing for this indication, while targeting Interleukin I has dramatically ameliorated autoinflammatory disorders with urticaria or urticaria-vasculitic-like lesions such as cold-induced autoinflammatory syndrome, Muckle-Wells syndrome, and Schnitzler syndrome.

Physical urticaria

The physical urticarias are a heterogeneous subgroup of chronic urticarias in which wheals can be reproducibly induced by different specific physical stimuli such as cold, heat, pressure, vibration, or sunlight. Physical urticarias comprise up to 25 % of chronic urticarias and occur more frequently in young adults. Symptoms, i.e. wheal and flare responses or angioedema, are usually limited to the skin areas exposed to the eliciting stimulus. However, generalised urticaria with variable extracutaneous manifestations can also occur. Some patients may also present with more than one physical urticaria. Skin lesions in physical urticaria result from mast cell activation and mediator release. The mechanisms by which physical stimuli activate skin mast cells are not fully understood. Because of this, trigger avoidance and symptomatic treatment are key therapeutic concepts for physical urticarias. Identification of the inducing physical trigger, including its individual thresholds, is necessary for an effective therapy. Here, we have summarized clinical features, diagnostic workup and therapy options for physical urticarias.

Mast cell dependent vascular changes associated with an acute response to cold immersion in primary contact urticaria

BACKGROUND

While a number of the consequences of mast cell degranulation within tissues have been documented including tissue-specific changes such as bronchospasm and the subsequent cellular infiltrate, there is little known about the immediate effects of mast cell degranulation on the associated vasculature, critical to understanding the evolution of mast cell dependent inflammation.

OBJECTIVE

To characterize the microcirculatory events that follow mast cell degranulation.

METHODOLOGY/PRINCIPAL FINDINGS

Perturbations in dermal blood flow, temperature and skin color were analyzed using laser-speckle contrast imaging, infrared and polarized-light colorimetry following cold-hand immersion (CHI) challenge in patients with cold-induced urticaria compared to the response in healthy controls. Evidence for mast cell degranulation was established by documentation of serum histamine levels and the localized release of tryptase in post-challenge urticarial biopsies. Laser-speckle contrast imaging quantified the attenuated response to cold challenge in patients on cetirizine. We found that the histamine-associated vascular response accompanying mast cell degranulation is rapid and extensive. At the tissue level, it is characterized by a uniform pattern of increased blood flow, thermal warming, vasodilation, and recruitment of collateral circulation. These vascular responses are modified by the administration of an antihistamine.

CONCLUSIONS/SIGNIFICANCE

Monitoring the hemodynamic responses within tissues that are associated with mast cell degranulation provides additional insight into the evolution of the acute inflammatory response and offers a unique approach to assess the effectiveness of treatment intervention.

Diagnosis and treatment of urticaria and angioedema: a worldwide perspective

: Urticaria and angioedema are common clinical conditions representing a major concern for physicians and patients alike. The World Allergy Organization (WAO), recognizing the importance of these diseases, has contributed to previous guidelines for the diagnosis and management of urticaria. The Scientific and Clinical Issues Council of WAO proposed the development of this global Position Paper to further enhance the clinical management of these disorders through the participation of renowned experts from all WAO regions of the world. Sections on definition and classification, prevalence, etiology and pathogenesis, diagnosis, treatment, and prognosis are based on the best scientific evidence presently available. Additional sections devoted to urticaria and angioedema in children and pregnant women, quality of life and patient-reported outcomes, and physical urticarias have been incorporated into this document. It is expected that this article will supplement recent international guidelines with the contribution of an expert panel designated by the WAO, increasing awareness of the importance of urticaria and angioedema in medical practice and will become a useful source of information for optimum patient management worldwide.

Cold urticaria, immunodeficiency, and autoimmunity related to PLCG2 deletions

BACKGROUND

Mendelian analysis of disorders of immune regulation can provide insight into molecular pathways associated with host defense and immune tolerance.

METHODS

We identified three families with a dominantly inherited complex of cold-induced urticaria, antibody deficiency, and susceptibility to infection and autoimmunity. Immunophenotyping methods included flow cytometry, analysis of serum immunoglobulins and autoantibodies, lymphocyte stimulation, and enzymatic assays. Genetic studies included linkage analysis, targeted Sanger sequencing, and next-generation whole-genome sequencing.

RESULTS

Cold urticaria occurred in all affected subjects. Other, variable manifestations included atopy, granulomatous rash, autoimmune thyroiditis, the presence of antinuclear antibodies, sinopulmonary infections, and common variable immunodeficiency. Levels of serum IgM and IgA and circulating natural killer cells and class-switched memory B cells were reduced. Linkage analysis showed a 7-Mb candidate interval on chromosome 16q in one family, overlapping by 3.5 Mb a disease-associated haplotype in a smaller family. This interval includes PLCG2, encoding phospholipase Cγ(2) (PLCγ(2)), a signaling molecule expressed in B cells, natural killer cells, and mast cells. Sequencing of complementary DNA revealed heterozygous transcripts lacking exon 19 in two families and lacking exons 20 through 22 in a third family. Genomic sequencing identified three distinct in-frame deletions that cosegregated with disease. These deletions, located within a region encoding an autoinhibitory domain, result in protein products with constitutive phospholipase activity. PLCG2-expressing cells had diminished cellular signaling at 37°C but enhanced signaling at subphysiologic temperatures.

CONCLUSIONS

Genomic deletions in PLCG2 cause gain of PLCγ(2) function, leading to signaling abnormalities in multiple leukocyte subsets and a phenotype encompassing both excessive and deficient immune function. (Funded by the National Institutes of Health Intramural Research Programs and others.).

Modern approaches to the diagnosis and treatment of cold contact urticaria

Cold contact urticaria (CCU) is a common subtype of physical urticaria characterized by itchy wheals and/or angioedema due to skin mast cell activation and the release of proinflammatory mediators after cold exposure. The underlying causes are largely unknown. When CCU is suspected, cold stimulation tests and threshold testing should be done to confirm the diagnosis and to determine the severity and course of CCU, respectively. Avoidance of critical cold exposure should be recommended but is often impossible, especially for severely affected patients with high temperature and low exposure time thresholds. Symptomatic treatment of choice is the use of modern, nonsedating antihistamines. Patients should be informed that complete protection from CCU symptom development may require increased doses of antihistamines. Standardizing cold provocation tests and further characterization of the natural course of CCU and its variants may lead to a better understanding of the disease-driving mechanisms.

Increased IgE-dependent mast cell activation and anaphylactic responses in mice lacking the calcium-activated nonselective cation channel TRPM4

Mast cells are key effector cells in allergic reactions. Aggregation of the receptor FcepsilonRI in mast cells triggers the influx of calcium (Ca(2+)) and the release of inflammatory mediators. Here we show that transient receptor potential TRPM4 proteins acted as calcium-activated nonselective cation channels and critically determined the driving force for Ca(2+) influx in mast cells. Trpm4(-/-) bone marrow-derived mast cells had more Ca(2+) entry than did TRPM4(+/+) cells after FcepsilonRI stimulation. Consequently, Trpm4(-/-) bone marrow-derived mast cells had augmented degranulation and released more histamine, leukotrienes and tumor necrosis factor. Trpm4(-/-) mice had a more severe IgE-mediated acute passive cutaneous anaphylactic response, whereas late-phase passive cutaneous anaphylaxis was not affected. Our results establish the physiological function of TRPM4 channels as critical regulators of Ca(2+) entry in mast cells.

Basophils and mast cells in chronic idiopathic urticaria

Chronic idiopathic urticaria (CIU) is diagnosed in patients when urticarial eruptions recur for more than 6 weeks, and no specific cause is determined. Given that urticaria resembles the lesions induced by injection of histamine or allergen into the skin, a role for mast cells or basophils has been proposed in the generation of localized urticarial lesions. However, currently, the exact mechanisms governing regional mast cell or basophil activation are unknown. In the past decade, there has been mounting interest in viewing CIU as an autoimmune disease, given the presence of circulating autoantibodies to IgE or the alpha subunit of the high-affinity IgE receptor (FceRI) in a subset of patients. In this review, we propose that in addition to autoantibodies, specific differences in the expression of FceRI-signaling molecules in the basophils or mast cells of CIU patients may contribute to the generation of urticarial eruptions.

Cold Urticaria: An Underrecognized Cause of Postsurgical Periorbital Swelling

PURPOSE

To report cold urticaria as an under-recognized cause of potential periorbital and facial edema after elective oculofacial plastic surgery.

METHODS

Retrospective case series of three patients with primary acquired cold urticaria with review of the clinical aspects of each of the cases.

RESULTS

Two of the patients had significant postoperative swelling attributed to primary acquired cold urticaria after the routine use of cool compresses to their surgical sites. The third patient had known primary acquired cold urticaria and required special perioperative management. All three patients ultimately had a good surgical outcome with no long-term sequelae.

CONCLUSIONS

Although primary acquired cold urticaria is generally not a serious condition, it can be easily overlooked and misdiagnosed as a localized adverse reaction to injected anesthetic, topical antibiotic ointments, or early preseptal cellulitis after eyelid or facial surgery. Rarely, this condition can be fatal and should be recognized by the surgeon to ensure both optimal surgical results and general medical management. Three simple screening questions should identify most patients with this disorder.

The spectrum of acquired and familial cold-induced urticaria/urticaria-like syndromes

Acquired cold urticaria syndromes represent one of the more common forms of physical urticaria. The syndromes are heterogenous, and a diagnostic classification is presented to facilitate collation for future studies. Acquired cold urticaria represents an excellent reproducible in vivo model to investigate the mechanisms of urticaria. The discussion includes clinical manifestations, laboratory features, pathogenesis, and management of these disorders. A description of familial types, particularly familial cold auto-inflammatory syndrome (FCAS) that is manifested by cold-evoked signs and symptoms of chronic inflammation, is included. FCAS historically has been included with acquired cold urticaria, even though the exanthem of FCAS is maculopapular caused by leukocytic infiltration. FCAS has become an important investigative syndrome, as it represents a reproducible in vivo model of chronic inflammation.

Coronary artery bypass grafting and aortic valve replacement with cold cardioplegia in a patient with cold-induced urticaria

BACKGROUND

Cold-induced urticaria is an uncommon but well described phenomenon in which a spectrum of responses may result from exposure to a cold stimulus. Patients with cold-induced urticaria who require cold cardiopulmonary bypass are at risk for hypotensive episodes.

OBJECTIVE

To describe the case of a 69-year-old man with documented cold-induced urticaria who required aortic valve replacement and coronary artery bypass surgery.

METHODS

After receiving a prophylactic anti-inflammatory regimen, the patient underwent cold cardiopulmonary bypass. After systemic cooling to 32 degrees C, cold blood cardioplegia was administered at 4 degrees C to obtain initial cardiac standstill. Thirty minutes before anticipated rewarming, anti-inflammatory medications were again administered. After rewarming to 37 degrees C for more than 33 minutes, he was successfully weaned from cardiopulmonary bypass without inotropic or pressor support and with normal pulmonary compliance. The prophylactic regimen was continued postoperatively.

RESULTS

The patient was extubated 11 hours after surgery, and with the exception of a brief, self-limited episode of atrial fibrillation, his course was uneventful. He experienced no urticaria, angioedema, or hypotension and was discharged home on the fourth postoperative day.

CONCLUSIONS

Although it is likely that the need for cold cardiopulmonary bypass surgery in patients with cold-induced urticaria is uncommon, it is encouraging that such a regimen may allow for the successful completion of the surgery.

Treatment of acquired cold urticaria with cetirizine and zafirlukast in combination

Acquired cold urticaria is an infrequent physical urticaria that can provoke severe systemic reactions. Histamine is the primary mediator, but leukotrienes are also involved in the pathogenesis. H(1) antihistamines are recommended as first-choice treatment, but their efficacy is sometimes unsatisfactory. On the basis of pathogenic knowledge, it can be hypothesized that a combination therapy with antihistamines and leukotriene receptor antagonists is more effective than each drug given alone. We tested this hypothesis in 2 patients with severe systemic cold urticaria poorly responsive to conventional therapy. The patients underwent 3 consecutive treatment regimens (each of 2 weeks): cetirizine (10 mg once a day); zafirlukast (20 mg twice a day); and their combination. They were clinically evaluated, after each regimen, by means of a visual analog scale and ice-cube test. The combination therapy was superior to the 2 drugs given alone, as testified by subjective and objective evaluations.

Cold urticaria

Cold urticaria is one form of urticaria that may be associated with other forms of physical urticarias. Frequency is generally estimated at two or three per 100. The triggering effect of cold is found at history taking in most of the cases. The urticaria is usually superficial, and more rarely associated with deep and/or mucosal urticaria. The diagnosis is based on history taking and the ice cube test. An exhaustive search for an etiologic factor is often unfruitful, and the presence of a cryopathy should lead to a complete work-up. Therapy of cold urticaria may prove to be difficult. In patients with secondary cold urticaria, underlying disease must be treated in order to resolve the skin symptoms. H1-antihistamines can be used but the clinical responses are highly variable. Short-time treatment with low concentration corticosteroids suppresses the symptoms only partially and temporarily. In patients who do not respond to previous treatments, induction of cold tolerance may be proposed but the procedure is difficult to carry out in daily life over an extended period. Key word: cryoglobulins.

Familial cold autoinflammatory syndrome: phenotype and genotype of an autosomal dominant periodic fever

BACKGROUND

Familial cold autoinflammatory syndrome (FCAS), commonly known as familial cold urticaria, is a rare autosomal dominant inflammatory disorder with episodic symptoms precipitated by exposure to cold.

OBJECTIVE

The goal of this study was to formulate clinical diagnostic criteria for FCAS in a large cohort in whom the diagnosis of FCAS was supported by genetic linkage to chromosome 1q44.

METHODS

We assessed 45 affected and 68 unaffected members from 6 American families. DNA analysis was performed to confirm linkage to chromosome 1q44. Clinical characteristics were determined by means of analysis of detailed questionnaires and medical histories.

RESULTS

Pedigree and genetic analyses confirmed autosomal dominant transmission and linkage to chromosome 1q44 in all families. The most consistent symptoms during attacks were rash (100%), fever (93%), arthralgia (96%), and conjunctivitis (84%). Age of onset was within the first 6 months of life in 95% of affected subjects. The average delay between cold exposure and onset of symptoms was 2.5 hours, and the average duration of an episode was 12 hours. Renal disease with amyloidosis occurs infrequently in FCAS (2%).

CONCLUSION

The most consistent clinical characteristics of FCAS that discriminate it from other periodic fevers are association with cold exposure, conjunctivitis, age of onset, duration of episodes, and an autosomal dominant inheritance pattern. On the basis of the analysis of genotype and phenotype of FCAS, we formulated clinical diagnostic criteria that can be used to distinguish FCAS from other hereditary periodic fever syndromes.

Treatment of cold urticaria

BACKGROUND

The etiology of cold contact urticaria is unknown and the therapy is therefore usually rather disappointing.

METHODS

This study reports therapeutic data on 42 patients with cold urticaria treated with a combination of terbutaline (3 x 5 mg a week, later 3 x 2.5 mg) and aminophylline-containing drugs (3 x 150 mg).

RESULTS

Complete remission of the urticarial response was achieved in 37 of the 42 patients.

CONCLUSIONS

The therapy was tolerated relatively well and the results are promising.

Cold urticaria as a model of mediator release: platelet factor 4, eosinophil cationic protein and histamine

Platelet factor 4 (PF4) has previously been linked to precipitation of cold urticaria (CU). The aim of the study was to assess the liberation of PF4, eosinophil cationic protein (ECP) and histamine after cold challenge in patients with CU. Ten controls and 8 patients with CU verified by clinical data and cold challenge test were investigated. Assessment of histamine, ECP and PF4 were done using radioimmunoassays. In patients histamine increased after 10 min on the challenged arm (NS), PF4 increase was statistically significant (p less than 0.05) both in patients and controls. ECP release showed no significant changes. Treatment with doxepin results in clinical improvement, but no changes in mediator release were seen. Thus, in contrast to previous reports an increase of PF4 was seen both in controls as well as in patients. An involvement of ECP was not ascertained. Our data suggest that neither basophils, nor eosinophils or platelets are directly involved in cold urticaria and that mast cell-dependent mediators may be of greater relevance.

Leukotriene E4 release in cold urticaria

Cold urticaria is a rare condition characterized by abnormal wealing following exposure to cold. It has been suggested that lipid-derived mediators may be involved in the pathogenesis of this condition. We have investigated whether the inflammatory reaction in cold urticaria is associated with the release of cysteinyl-leukotrienes. Leukotriene E4 (LTE4; a stable metabolic product of LTC4 and LTD4) and histamine were measured in the blood draining the site of a cold-challenge in five patients with clinical histories of cold urticaria. Three of the patients showed a typical clinical response to the challenge, and this was associated with an increase in the concentration of LTE4 and histamine. No increase in LTE4 or histamine levels were observed following cold challenge in the non-responding individuals.

Prevalence and functional role of anti-IgE autoantibodies in urticarial syndromes

The prevalence of autoantibodies of immunoglobulin G (IgG) and immunoglobulin M (IgM) classes directed against myeloma immunoglobulin E (IgE) were determined in distinct subsets of urticaria, using an enzyme immunoassay. IgG anti-IgE antibodies were found in five of nine patients (55%) with cold urticaria, four of eight patients (50%) with urticarial vasculitis, and three of six patients (50%) with chronic urticaria. IgM anti-IgE antibodies were found exclusively in cold urticaria (two of nine patients, 22%). Heating of these sera increased the binding to IgE, suggesting immune complex formation. Several positive sera were capable of inducing histamine release from normal peripheral basophils and caused a wheal-flare response upon intradermal injection. Sera containing such autoantibodies from three cold urticaria patients were studied for passive transfer of cold sensitivity. One serum containing IgG anti-IgE gave a strongly positive transfer test at 5 h but not 48 h, suggesting a pathogenic role for the IgG.

Prostaglandin D2 and histamine release in cold urticaria

Prostaglandin (PG) D2 and histamine concentrations have been measured in blood draining cold-challenged forearm skin in patients with cold urticaria. Local venous concentrations of both histamine and PGD2 rose in four patients who developed a whealing response. Plasma histamine concentration increased from a mean resting value of 0.24 +/- 0.09 (SD) ng/ml to peak values of 16.9 to 96.6 ng/ml. Resting concentrations of PGD2 were below the limit of detection (5 pg/ml) in three patients and 62 and 27 pg/ml in the fourth. Peak plasma PGD2 concentration after challenge ranged from 166 to 279 pg/ml. Time course of histamine and PGD2 release was similar with peak concentrations at 6 and 10 minutes, respectively. The maximum clinical response occurred between 10 and 20 minutes after challenge. Our findings demonstrate that PGD2 is produced in association with mast cell degranulation in man, but the amount, relative to histamine, is low. Despite its high potency in production of inflammatory effects, PGD2 probably has only minor direct effects in cold urticaria, although it may act to potentiate other mediators.