Cold urticaria. Immunologic studies

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.

Cold urticaria in a pediatric cohort: Clinical characteristics, management, and natural history

BACKGROUND

Cold urticaria (coldU) is associated with substantial morbidity and risk of fatality. Data on coldU in children are sparse. We aimed to evaluate the clinical characteristics, management, risk of associated anaphylaxis, and resolution rate of coldU in a pediatric cohort. Additionally, we sought to compare these metrics to children with chronic spontaneous urticaria (CSU).

METHODS

We prospectively enrolled children with coldU from 2013-2021 in a cohort study at the Montreal Children's Hospital and an affiliated allergy clinic. Data for comparison with participants with solely CSU were extracted from a previous study. Data on demographics, comorbidities, severity of presentation, management, and laboratory values were collected at study entry. Patients were contacted yearly to assess for resolution.

RESULTS

Fifty-two children with cold urticaria were recruited, 51.9% were female and the median age of symptom onset was 9.5 years. Most patients were managed with second-generation H1-antihistamines (sgAHs). Well-controlled disease on sgAHs was negatively associated with concomitant CSU (adjusted odds ratio (aOR) = 0.69 [95%CI: 0.53, 0.92]). Elevated eosinophils were associated with cold-induced anaphylaxis (coldA; aOR = 1.38 [95%CI: 1.04, 1.83]), which occurred in 17.3% of patients. The resolution rate of coldU was 4.8 per 100 patient-years, which was lower than that of CSU (adjusted hazard ratio = 0.43 [95%CI: 0.21, 0.89], p < 10^-2 ).

CONCLUSION

Pediatric coldU bears a substantial risk of anaphylaxis and a low-resolution rate. Absolute eosinophil count and co-existing CSU may be useful predictive factors.

Cryoglobulins, Cryofibrinogens, and Cold Agglutinins in Cold Urticaria: Literature Review, Retrospective Patient Analysis, and Observational Study in 49 Patients

Introduction

Cryoproteins, such as cryoglobulins, cryofibrinogens and cold agglutinins, precipitate at low temperatures or agglutinate erythrocytes and dissolve again when warmed. Their pathogenetic and diagnostic importance in cold urticaria (ColdU) is unclear. In this study, we aimed to characterize the prevalence of cryoproteins in patients with ColdU.

Methods

We conducted 3 analyses: i) a systematic review and meta-analysis of published data using an adapted version of the Joanna Briggs Institute's critical appraisal tool for case series, ii) a retrospective analysis of 293 ColdU patients treated at our Urticaria Center of Reference and Excellence (UCARE) from 2014 to 2019, and iii) a prospective observational study, from July 2019 to July 2020, with 49 ColdU patients as defined by the EAACI/GA2LEN/EDF/UNEV consensus recommendations.

Results

Our systematic review identified 14 relevant studies with a total of 1151 ColdU patients. The meta-analyses showed that 3.0% (19/628), 1.1% (4/357) and 0.7% (2/283) of patients had elevated levels of cryoglobulins, cryofibrinogens and cold agglutinins, respectively. Our retrospective analyses showed that cryoproteins were assessed in 4.1% (12/293) of ColdU patients. None of 9 ColdU patients had cryoglobulins, and one of 5 had cold agglutinins. In our prospective study, none of our patients had detectable cryoglobulins (0/48) or cryofibrinogens (0/48), but 4.3% (2/46) of patients had cold agglutinins (without any known underlying autoimmune or hematological disorder).

Conclusion

Our investigation suggests that only very few ColdU patients exhibit cryoproteins and that the pathogenesis of ColdU is driven by other mechanisms, which remain to be identified and characterized in detail.

Cold Agglutinins and Cryoglobulins Associate With Clinical and Laboratory Parameters of Cold Urticaria

Mast cell-activating signals in cold urticaria are not yet well defined and are likely to be heterogeneous. Cold agglutinins and cryoglobulins have been described as factors possibly associated with cold urticaria, but their relevance has not been explained. We performed a single-center prospective cohort study of 35 cold urticaria patients. Cold agglutinin and cryoglobulin test results, demographics, detailed history data, cold stimulation test results, complete blood count values, C-reactive protein, total immunoglobulin E levels, and basal serum tryptase levels were analyzed. Forty six percent (n = 16) of 35 tested patients had a positive cold agglutinin test and 27% (n = 9) of 33 tested patients had a positive cryoglobulin test. Cold agglutinin positive patients, when compared to cold agglutinin negative ones, were mainly female (P = 0.030). No gender-association was found for cryoglobulins. A positive cold agglutinin test, but not a positive cryoglobulin test, was associated with a higher rate of reactions triggered by cold ambient air (P = 0.009) or immersion in cold water (P = 0.041), and aggravated by increased summer humidity (P = 0.007). Additionally, patients with a positive cold agglutinin test had a higher frequency of angioedema triggered by ingestion of cold foods or drinks (P = 0.043), and lower disease control based on Urticaria Control Test (P = 0.023). Cold agglutinin levels correlated with erythrocyte counts (r = −0.372, P = 0.028) and monocyte counts (r = −0.425, P = 0.011). Cryoglobulin concentrations correlated with basal serum tryptase levels (r = 0.733, P = 0.025) and cold urticaria duration (r = 0.683, P = 0.042). Results of our study suggest that cold agglutinins and cryoglobulins, in a subpopulation of cold urticaria patients, are linked to the course and possibly the pathogenesis of their disease.

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.

How to Approach Chronic Inducible Urticaria

Chronic inducible urticaria (CIndU) is a group of chronic urticarias characterized by the appearance of recurrent wheals, recurrent angioedema or both, as a response to specific triggers. CIndU includes both physical (symptomatic dermographism, cold and heat urticaria, delayed pressure urticaria, solar urticaria, and vibratory urticaria) and nonphysical urticarias (cholinergic urticaria, contact and aquagenic urticaria). Here, we review the different forms of CIndU with an emphasis on symptomatic dermographism, cold urticaria, cholinergic urticaria, and delayed pressure urticaria. We discuss the clinical features, the diagnostic workup including provocation and threshold testing, and available treatment options.

Treatments of cold urticaria: A systematic review

BACKGROUND

Several treatment options for cold urticaria (ColdU) have been studied and reported, but systematic reviews and meta-analyses are limited.

OBJECTIVES

We sought to meta-analyze and review the efficacy and safety of ColdU treatments.

METHODS

We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) recommendations. Suitable reports were identified by searching PubMed, Scopus, and Web of Science. Our systematic review included 16 studies, 9 of which met the eligibility criteria for the meta-analysis. We analyzed the effects of treatments on critical temperature thresholds (CTTs) and critical stimulation time thresholds (CSTTs), as well as on rates of complete response and adverse events.

RESULTS

Our pooled meta-analyses showed that nonsedating second-generation H₁-antihistamines (nsAHs) are effective in the treatment of ColdU and that updosing of nsAHs significantly reduced CTTs relative to their own standard doses and placebos. In 4 studies involving CSTTs, updosing of nsAHs also resulted in significantly better CSTTs than their own standard doses or placebos. Omalizumab resulted in a marked reduction of CTTs in H₁-antihistamine-resistant patients. Of 118 adverse events in 8 studies, standard-dose nsAHs, updosed nsAHs, and omalizumab produced lower numbers of adverse events than first-generation antihistamines.

CONCLUSIONS

Our study showed that greater dosages of nsAHs were more effective than standard dosages in controlling ColdU symptoms. Increasing the dosages was not significantly associated with higher adverse event rates. Omalizumab at 150 and 300 mg every 4 weeks was shown to be effective for patients with ColdU refractory to antihistamines.

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.

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.

Cold-Induced Skin Disorders

Background:

Humans are commonly exposed to extremes in temperature. Fortunately, our skin behaves as an anatomic and physiologic barrier during these periods. Exposure to cold temperatures may result in a variety of symptoms and disorders.

Objective:

Our current understanding of the pathophysiology, clinical presentation, and therapies of cold-induced skin disorders are reviewed.

Methods:

Studies, reviews, and book chapters that contained information on cold-induced skin disorders were reviewed.

Conclusion:

Cold-induced skin disorders are a heterogeneous group of disorders that cause great morbidity, particularly in cold climates. These entities can be classified as physiologic or pathologic responses to freezing or nonfreezing cold exposure.

Histamine h2 receptor signaling in the pathogenesis of sepsis: studies in a murine diabetes model

Type 1 diabetes enhances susceptibility to infection and favors the sepsis development. In addition, diabetic mice produced higher levels of histamine in several tissues and in the blood after LPS stimulation than nondiabetic mice. In this study, we aimed to explore the role of mast cells (MCs) and histamine in neutrophil migration and, consequently, infection control in diabetic mice with mild sepsis (MS) induced by cecum ligation and puncture. We used female BALB/c, MC-sufficient (WB/B6), MC-deficient (W/W(v)), and NOD mice. Diabetic mice given MS displayed 100% mortality within 24 h, whereas all nondiabetic mice survived for at least 5 d. The mortality rate of diabetic mice was reduced to 57% after the depletion of MC granules with compound 48/80. Moreover, this pretreatment increased neutrophil migration to the focus of infection, which reduced systemic inflammatory response and bacteremia. The downregulation of CXCR2 and upregulation of G protein-coupled receptor kinase 2 in neutrophils was prevented by pretreatment of diabetic mice given MS with compound 48/80. In addition, blocking the histamine H2 receptor restored neutrophil migration, enhanced CXCR2 expression, decreased bacteremia, and improved sepsis survival in alloxan-induced diabetic and spontaneous NOD mice. Finally, diabetic W/W(v) mice had neutrophil migration to the peritoneal cavity, increased CXCR2 expression, and reduced bacteremia compared with diabetic WB/B6 mice. These results demonstrate that histamine released by MCs reduces diabetic host resistance to septic peritonitis in mice.

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.

Examination of the role of TRPM8 in human mast cell activation and its relevance to the etiology of cold-induced urticaria

Mast cells are considered the primary initiators of allergic diseases as a consequence of the release of multiple inflammatory mediators on activation. Although predominately activated through antigen-mediated aggregation of IgE-occupied-FcɛRI, they can also be induced to release mediators by other receptors and environmental stimuli. Based on studies conducted in the RBL 2H3 rodent mast cell line, the transient receptor potential melastatin 8 (TRPM8) cation channel has been implicated in the activation of mast cells in response to cold and, by inference, the development of urticaria. Here we investigated the expression and role of TRPM8 receptor, in both human and mouse non-transformed cells, with the aim of exploring the potential link between TRPM8 and the pathology of cold urticaria in humans. Although expressed in mouse mast cells, we found no evidence of TRPM8 expression in human mast cells or functional mutations in TRPM8 in cold urticaria patients. Furthermore, neither mouse nor human primary cultured mast cells degranulated in response to cold challenge or TRPM8 agonists and mast cell reactivity was unaffected in Trpm8(-/-) mice. From these data, we conclude that TRPM8 is unlikely to directly regulate mast cell activation in cold urticaria. Thus, alternative mechanisms likely exist for the pathogenesis of this disease.

Cold urticaria associated with acute serologic toxoplasmosis

Cold urticaria is defined as a urticarial and/or angioedematous reaction of the skin to contact with cold objects, water or air. Types of urticaria associated with infectious diseases, such as mononucleosis, rubeola, varicella, syphilis, hepatitis, and HIV infection have been reported. We present the case of a patient who developed cold urticaria associated with acute serologic toxoplasmosis. The patient was a 34-year-old man who for the previous 2 months had presented cutaneous pruritus accompanied by several papular lesions in parts of the skin exposed to cold as well as those in contact with cold water. The result of an "ice-cube test" was positive. Serologic tests for Toxoplasma gondii showed an IgG level of 68 UI/ml and were positive for IgM, while a test for cryoglobulins was positive. One month later cryoglobulins were negative and a serologic test for T. gondii showed an IgG concentration of 75 UI/ml and positive IgM. Three months later cryoglobulins were still negative, IgG for T. gondii was 84 UI/ml, and IgM was positive. After 6 months cryoglobulins were still negative, IgG level was 68 UI/ml and IgM was still slightly positive. In the final evaluation, 14 months later, IgG level was 32 UI/ml and IgM was negative. The patient continues to present clinical manifestations of cold urticaria, although he has experienced some improvement and his tolerance to cold has increased after treatment with cetirizine.

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.

Chronic urticaria

Chronic urticaria remains a major problem in terms of etiology, investigation, and management. It is important to identify patients in whom physical urticaria is the principal cause of disability. Once confirmed by appropriate challenge testing, no further investigation is required. Urticarial vasculitis (UV) is a major differential diagnosis of "idiopathic" urticaria (CIU). I perform biopsy of most patients in this category because UV cannot be considered confirmed in the absence of histologic evidence. Patients with confirmed UV need to be thoroughly investigated for paraproteins, lupus erythematosus hepatitis B and C, and inflammatory bowel disease. Of patients with CIU, a few (<5%) prove to have food additive reactivity confirmed by placebo-controlled challenge testing. There is no convincing evidence of the involvement of Helicobacter pylori or parasite infestation as a cause of chronic urticaria, although H pylori could have an indirect role. Recently it has become clear that 27% to 50% of patients with CIU have functional autoantibodies directed against the alpha-chain of the high-affinity IgE receptor or less commonly against IgG. These antibodies, whose involvement has now been independently confirmed in several centers, are identified by autologous serum skin testing and confirmed by histamine release studies or immunoblotting. Their removal (by intravenous Ig or plasmapheresis) or treatment by cyclosporine has proved highly beneficial in severely affected patients. However, the routine treatment of all CIU patients, irrespective of etiology, remains the judicious use of H(1) antihistamines.

Tumor necrosis factor-alpha release during systemic reaction in cold urticaria

Primary cold urticaria (PCU) characterized by the association of urticaria, angioedema, and sometimes a shock-like reaction after cold exposure, is usually considered to be linked with histamine and prostaglandin D2 release by mast cells. To determine the involvement of cytokines, we studied the release of tumor necrosis factor-alpha (TNF-alpha) in the blood of the efferent vein after immersion of the hand in chilled water. Five patients with PCU were compared with a control population (three patients with nonphysical urticaria and three healthy subjects). Among patients with PCU who underwent the cold immersion test, two exhibited a shock-like reaction with a large urticarial plaque (patients 1 and 2), one had only a mild cutaneous reaction, and two had no reaction. Patient 1 was reevaluated after 6 months of treatment with H1 and H2 antihistamines: he did not respond to this challenge. All controls were strictly negative. Histamine was released within the first minute after the challenge in the three patients with PCU, but at a higher level for the two patients who had a systemic reaction. TNF-alpha was undetectable in the blood of the patient with only a mild cutaneous reaction, whereas TNF-alpha release was observed for the two patients with a systemic reaction, 2 and 6 minutes after the end of the cold immersion test. The two other patients and the control subjects released neither histamine nor TNF-alpha. In parallel, pathologic and immunohistochemical (with a rabbit anti-TNF-alpha antibody) studies were performed on skin biopsy specimens collected 10 minutes after ice-cube test.(ABSTRACT TRUNCATED AT 250 WORDS)

Cold-induced urticaria and angioedema: diagnosis and management

The physical urticarias compromise a heterogeneous group of disorders characterized by their propensity to form urticarial lesions after exposure to certain physical stimuli, such as heat, vibration, or cold. Although generally benign, systemic hypotension and angioedematous airway compromise are known life-threatening complications. We present the case of a man who experienced benign angioedematous changes in response to cold exposure, and discuss the clinical course, diagnosis, and management of cold urticaria.

Localized, perifollicular cold urticaria

Cold urticaria is a condition with many clinical variants. We present the case of a young woman with a localized, perifollicular form that we believe represents a new and distinct clinical subtype of cold urticaria. We review other established clinical subtypes of cold urticaria.

Temperature-dependent skin disorders

The skin is important in preserving homeostasis between man and his environment. One main role of the skin is in thermoregulation, where cutaneous blood flow, and hence skin temperature, vary widely in order to help preserve core body temperature. Under extreme conditions, frostbite or burns may occur. Prolonged exposure to moderate degrees of heat or cold can result in erythema ab igne and chilblains. Temperature plays a direct role in some of the physical urticarias and is one of several important pathogenic factors in conditions such as Raynaud's syndrome, cold panniculitis, and cryoglobulinemia. These and other temperature-dependent skin disorders are reviewed.

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.

Cold-induced dysaesthesia in acute idiopathic polyneuritis

Two cases are reported of cold-induced dysaesthesia occurring during an attack of acute idiopathic polyneuritis. Two similar cases found in the literature are reviewed. It is suggested that the dysaesthesia may be a localized symptom of cold sensitivity, with an initiating trigger in common with acute idiopathic polyneuritis.

Symptomatic dermographism (factitious urticaria)--passive transfer experiments from human to monkey

Passive transfer experiments were carried out on three species of monkey, Macaca mulatta, Macaca nemestrina and Macaca fascicularis, using human serum from patients affected with severe symptomatic dermographism (factitious urticaria), cholinergic urticaria, chronic idiopathic urticaria and normal subjects. The monkeys were tested for dermographism by means of a calibrated dermographometer 24 h after intradermal injection of the serum, using Evans blue as a marker. Positive responses were seen initially in the M. nemestrina. Four sites injected with serum from patients with severe symptomatic dermographism gave positive responses, one site injected with serum from a normal subject produced a faint response. One of the four responses was reproduced one month later in M. fascicularis. These results indicate that passive transfer of dermographism is possible from human to monkey.

Clinical characteristics of cold-induced systemic reactions in acquired cold urticaria syndromes: recommendations for prevention of this complication and a proposal for a diagnostic classification of cold urticaria

The acquired cold urticaria (ACU) syndromes consists of nonfamilial heterogeneous disorders characterized by urticaria, angioedema, and occasionally symptoms of hypotension after cold exposure. In a study of 50 consecutive patients with ACU syndromes, it was observed that 70% experienced cold-induced systemic reactions, most frequently with aquatic activities. Patients with ACU syndromes were categorized by their response to an experimental cold-stimulation time test (CSTT) i.e., minimum time threshold of cold stimulation required to induce a coalescent wheal. One subpopulation of patients with ACU syndromes with positive CSTTs of 3 minutes or less experienced the highest incidence (68%; 13/19) of severe systemic reactions with hypotensive symptoms after natural cold exposure. However, 32% of patients with ACU syndromes (6/19) who experienced cold-induced systemic reactions with hypotension had a negative CSTT or a positive test of greater than 3 minutes. These observations indicate that all patients with ACU with active histories of cold urticaria are at risk to develop systemic reactions to cold and should therefore refrain from participating in aquatic activities. In addition, high-risk patients should receive prophylactic medications (i.e., cyproheptadine or doxepin) that are effective in suppressing this disorder. A diagnostic classification of cold urticaria is presented. This classification permits a more specific definition of the various cold urticaria disorders that comprise the ACU syndromes.

Cold urticaria. Clinical findings in 220 patients

Patients with cold urticaria, a total of 220, were studied in Finland. Sixty-three percent of the patients were female. The diagnosis was based on a positive ice cube test in 90% of cases, and the other cold tests were needed to certify the diagnosis for the remainder of patients. The mean age at the onset of the disease was 25.1 years (range, 1-74), and the mean duration of symptoms was 6.3 years (range, 3 weeks to 37 years). Cold urticaria symptoms had disappeared in fifty-three patients (24%), but there was a recurrence of the disease in twelve. Idiopathic (primary acquired) cold urticaria was present in 96% of the patients. Only two patients had a secondary acquired cold urticaria. Two patients had cold-induced, "cholinergic" urticaria, and four patients had a delayed type of cold urticaria. Twenty-one percent of the patients had dermatographism, 8% had cholinergic urticaria, and two patients (1%) had heat urticaria concurrently with cold urticaria.

Dermographism (mechanical urticaria) mediated by IgM

Sera of three patients with symptomatic mechanical urticaria caused an immediate weal and flare reaction when injected intracutaneously into related recipients, and serum of one patient caused the same reaction in his own skin. Pretreatment of test skin sites with Compound 48/80 abolished or greatly reduced the reaction. This weal-producing substance was found in the same fraction as IgM in Sephadex G-200 gel filtration, was stable to heat treatment (56 degrees C, 4 h) and labile to 2-mercaptoethanol treatment. An immunoadsorption study using anti-IgM serum identified this weal-producing substance as IgM.

Urticaria and angio-oedema

Urticaria and angio-oedema are a symptom complex covering a wide range of clinical disorders. Specific types are now well described, and it appears that many cases of idiopathic chronic urticaria which make up the vast majority of patients referred for assessment are due to intolerance to natural salicylates, preservatives and colouring agents. There is, therefore, an urgent need for legislation to enforce the clear identification of these chemicals in processed food and drugs.

Involvement of sensory nerve endings in cold and heat urticaria

The involvement of sensory nerve endings in acquired cold and heat urticaria was studied in 8 patients. After repeated topical application of capsaicin, the skin was tested for whealing with cold and heat stimuli. Capsaicin pretreatment prevented the urticarial responses for 4-7 days. Since capsaicin is known to induce selective impairment of the chemosensitive nerve endings, the results suggest that these nerve fibers may play an important role in acquired cold and heat urticaria. The possible mechanisms are discussed.

Treatment of urticaria

Urticaria represents a wide variety of conditions characterized by urticarial papules, wheals, and angioedema. The number of potential causes of urticaria is legion, but a diligent search by careful history and examination is indicated. Laboratory testing depends upon the specific situation, but routine screening examinations are not cost effective. Histamine from mast cells plays an important role in urticaria. Multiple factors, such as aspirin and other nonsteroidal anti-inflammatory agents, direct histamine-releasing agents (including benzoates), tartrazine and other azo dyes, and perhaps blockers of beta 2-adrenergic activity and H2 receptors, adversely influence histamine release either directly or indirectly. Vasodilation is also detrimental. Treatment of both acute and chronic urticaria necessitates removal of the patient from aggravating factors as well as the cause of the outbreak (if one can be found), along with effective antihistaminic agents and perhaps beta 2-adrenergic agonists. Treatment of specific entities within the urticarial group is briefly outlined in this article.