Idiopathic anaphylaxis: a series of 335 cases

Treatment of idiopathic anaphylaxis with dupilumab: a case report

BACKGROUND

Anaphylaxis is an acute, potentially life-threatening allergic reaction that typically occurs after exposure to a trigger, while idiopathic anaphylaxis (IA) occurs in the absence of a trigger. Acute management of both triggered anaphylaxis and IA relies on the use of epinephrine. In some patients with recurrent IA, glucocorticoid prophylaxis with prednisone can be effective. While there is currently no high quality evidence for the use of other prophylactic options to prevent recurrent IA, evolving data exists to support the consideration of biologics that target IgE or the Th2 pathway.

CASE PRESENTATION

We present the case of a 28 year old female with no atopic or autoimmune history with recurrent episodes of IA since childhood occurring up to twice weekly. There was improvement in acute symptoms with administration of first or second generation antihistamines and/or intramuscular epinephrine. Without an identifiable trigger, she was diagnosed with IA and frequent idiopathic urticaria and omalizumab was added to her treatment regimen with improvement in symptom frequency. After being lost to follow up, she had recurrence of symptom frequency and severity without omalizumab therapy and subsequently presented to our institution. Her workup at this point was negative for food allergy, alpha gal syndrome, systemic mastocytosis, hereditary alpha tryptasemia, carcinoid syndrome, and pheochromocytoma, and she was trialed on dupilumab with near resolution of her symptom frequency over a six month time period.

CONCLUSION

Recurrent IA is a diagnosis of exclusion that is associated with high morbidity. Prophylaxis remains an area of uncertainty, although prednisone has been effective in some cases. When prednisone is contraindicated or ineffective for the prevention of IA, biologic therapies that target IgE or the Th2 pathway may present a reasonable consideration. This case adds support to the suggestion that dupilumab may be a logical off-label consideration for prophylaxis of recurrent IA. The data for dupilumab in this clinical scenario is still very limited, and further research is required before any recommendation can be made.

Anaphylaxis: Epidemiology and Differential Diagnosis

Anaphylaxis-related emergency department (ED) visits and hospitalizations are increasing. Triggers for anaphylaxis include food, medications, and stinging insects. Idiopathic anaphylaxis accounts for 30% to 60% of cases of anaphylaxis in adults and up to 10% of cases in children with novel allergens such as galactose-α-1,3 galactose reclassifying these cases. Recent practice guidelines have recommended against the routine use of systemic corticosteroids and antihistamines for the prevention of biphasic reactions and recommend an extended observation, up to 6 hours, for those with risk factors for biphasic anaphylaxis and those with lack of access to epinephrine and to emergency medical services.

Idiopathic anaphylaxis: Diagnosis and management

Introduction: Idiopathic anaphylaxis (IA) is a diagnosis of exclusion and is based on the inability to identify a causal relationship between a trigger and an anaphylactic event, despite a detailed patient history and careful diagnostic assessment. The prevalence of IA among the subset of people who experienced anaphylaxis is challenging to estimate and varies widely, from 10 to 60%; most commonly noted is ∼20% in the adult anaphylactic population. Comorbid atopic conditions, such as food allergy, allergic rhinitis, and asthma, are present in up to 48% of patients with IA. Improved diagnostic technologies and an increased understanding of conditions that manifest with symptoms associated with anaphylaxis have improved the ability to determine a more accurate diagnosis for patients who may have been initially diagnosed with IA. Methods: Literature search was conducted on PubMed, Google Scholar and Embase. Results: Galactose-α-1,3-galactose (α-gal) allergy, mast cell disorders, and hereditary a-tryptasemia are a few differential diagnoses that should be considered in patients with IA. Unlike food allergy, when anaphylaxis occurs within minutes to 2 hours after allergen consumption, α-gal allergy is a 3-6-hour delayed immunoglobulin E-mediated anaphylactic reaction to a carbohydrate epitope found in red meat (e.g., beef, lamb, pork). The more recently described hereditary α-tryptasemia is an inherited autosomal dominant genetic trait caused by increased germline copies of tryptase human gene alpha-beta 1 (TPSAB1), which encodes α tryptase and is associated with elevated baseline serum tryptase. Acute management of IA consists of carrying an epinephrine autoinjector to be administered immediately at the first signs of anaphylaxis. Long-term management for IA with antihistamines and other agents aims to potentially reduce the frequency and severity of the anaphylactic reactions, although the evidence is limited. Biologics are potentially steroid-sparing for patients with IA; however, more research on IA therapies is needed. Conclusion: The lack of diagnostic criteria, finite treatment options, and intricacies of making a differential diagnosis make IA challenging for patients and clinicians to manage.

Mastocytosis and Mast Cell Activation Disorders: Clearing the Air

Mast cells are derived from hematopoietic stem cell precursors and are essential to the genesis and manifestations of the allergic response. Activation of these cells by allergens leads to degranulation and elaboration of inflammatory mediators, responsible for regulating the acute dramatic inflammatory response seen. Mast cells have also been incriminated in such diverse disorders as malignancy, arthritis, coronary artery disease, and osteoporosis. There has been a recent explosion in our understanding of the mast cell and the associated clinical conditions that affect this cell type. Some mast cell disorders are associated with specific genetic mutations (such as the D816V gain-of-function mutation) with resultant clonal disease. Such disorders include cutaneous mastocytosis, systemic mastocytosis (SM), its variants (indolent/ISM, smoldering/SSM, aggressive systemic mastocytosis/ASM) and clonal (or monoclonal) mast cell activation disorders or syndromes (CMCAS/MMAS). Besides clonal mast cell activations disorders/CMCAS (also referred to as monoclonal mast cell activation syndromes/MMAS), mast cell activation can also occur secondary to allergic, inflammatory, or paraneoplastic disease. Some disorders are idiopathic as their molecular pathogenesis and evolution are unclear. A genetic disorder, referred to as hereditary alpha-tryptasemia (HαT) has also been described recently. This condition has been shown to be associated with increased severity of allergic and anaphylactic reactions and may interact variably with primary and secondary mast cell disease, resulting in complex combined disorders. The role of this review is to clarify the classification of mast cell disorders, point to molecular aspects of mast cell signaling, elucidate underlying genetic defects, and provide approaches to targeted therapies that may benefit such patients.

Idiopathic Anaphylaxis: A Form of Mast Cell Activation Syndrome

Idiopathic anaphylaxis is a condition caused by paroxysmal episodes of sudden-onset multiorgan involvement variably including laryngeal edema, urticaria, bronchoconstriction, dyspnea, hypoxia, abdominal pain, nausea, vomiting, diarrhea, and hypotension. Rarely, the episodes can lead to cardiovascular collapse and death in the absence of a clear trigger, especially in the presence of other cardiovascular comorbidities. Elevated mast cell mediators such as tryptase and histamine have been reported during episodes, and mast cells are considered the primary cells responsible for driving anaphylaxis in humans. Basophils also secrete histamine and LTC4 when activated and theoretically can contribute to symptoms. As our understanding of mast cell disorders continue to grow, the classification for these disorders evolves. The purpose of this article was 2-fold: to review the epidemiology, clinical manifestations, and diagnosis of idiopathic anaphylaxis and to discuss the classification of idiopathic anaphylaxis within the broader context of mast cell activation disorders.

Idiopathic Anaphylaxis: a Perplexing Diagnostic Challenge for Allergists

PURPOSE OF REVIEW

The aim of this systematic review is to present the proposed theories of pathogenesis for idiopathic anaphylaxis (IA), to discuss its classification, its diagnostic approach, and management.

RECENT FINDINGS

IA represents a major diagnostic challenge and is diagnosed when excluding the possible identifiable triggers of anaphylaxis. The current research, however, revealed that certain conditions including mastocytosis, mast cell activation syndromes, and hereditary alpha tryptasemia can masquerade and overlap with its symptomatology. Also, newly identified galactose-alpha-1,3-galactose mammalian red meat allergy has recently been recognized as underlying cause of anaphylaxis in some cases that were previously considered as IA. IA comprises a heterogenous group of conditions where, in some cases, inherently dysfunctional mast cells play a role in pathogenesis. The standard trigger avoidance strategies are ineffective, and episodes are unpredictable. Therefore, prompt recognition and treatment as well as prophylaxis are critical. The patients should always carry an epinephrine autoinjector.

Management Strategies Of Idiopathic Anaphylaxis In The Emergency Room: Current Perspectives

Background

Idiopathic anaphylaxis (IA) is a diagnosis of exclusion and represents a major diagnostic and management challenge. There are no current guidelines for diagnosis and management of IA. We aim to present a systematic review of the literature on adult and pediatric IA.

Methods

We conducted a systematic review of original articles published in the past 22 years regarding diagnosis and management strategies of adult and pediatric IA.

Results

The current proposed diagnostic approach and treatment regimens are based on a few small studies. Future large-scale studies are required. IA is a diagnosis of exclusion and should be made only after extensive evaluation excludes potential anaphylaxis triggers as well as non-allergic conditions with a similar presentation. There is currently no diagnostic consensus for IA. Furthermore, the current proposed treatment regimens are limited and rely on prophylactic treatment with antihistamines and prednisone for patients with frequent episodes. However, daily treatment with systemic steroids has well-recognized serious adverse effects. More recently, the use of biologics was suggested to benefit patients with IA, although the optimal management protocol is not yet established.

Conclusion

Future studies are needed to optimize diagnosis and treatment strategies in adult and pediatric cases of IA. Omalizumab may be a promising novel therapeutic option for adult and pediatric IA.

Idiopathic anaphylaxis yardstick: Practical recommendations for clinical practice

Anaphylaxis is considered idiopathic when there is no known trigger. The signs and symptoms of idiopathic anaphylaxis (IA) are identical to those of anaphylaxis because of a known cause and can include cutaneous, circulatory, respiratory, gastrointestinal, and neurologic symptoms. Idiopathic anaphylaxis can be a frustrating disease for patients and health care providers. Episodes are unpredictable, and differential diagnosis is challenging. Current anaphylaxis guidelines have little specific guidance regarding differential diagnosis and long-term management of IA. Therefore, the objective of the Idiopathic Anaphylaxis Yardstick is to use published data and the authors' combined clinical experience to provide practical recommendations for the diagnosis and management of patients with IA.

Idiopathic anaphylaxis

Idiopathic anaphylaxis (IA) or spontaneous anaphylaxis is a diagnosis of exclusion when no cause can be identified. The exact incidence and prevalence of IA are not known. The clinical manifestations of IA are similar to other known causes of anaphylaxis. A typical attack is usually acute in onset and can worsen over minutes to a few hours. The pathophysiology of IA has not yet been fully elucidated, although an IgE-mediated pathway by hitherto unidentified trigger/s might be the main underlying mechanism. Elevated concentrations of urinary histamine and its metabolite, methylimidazole acetic acid, plasma histamine and serum tryptase have been reported, consistent with mast cell activation. There is some evidence that corticosteroids reduce the frequency and severity of episodes of IA, consistent with a steroid-responsive condition. Important differential diagnoses of IA include galactose alpha-1,3 galactose (a carbohydrate contained in red meat) allergy, pigeon tick bite (Argax reflexus), wheat-dependent exercise-induced anaphylaxis, Anisakis simplex allergy and mast cell disorders. Other differential diagnoses include "allergy-mimics" such as asthma masquerading as anaphylaxis, undifferentiated somatoform disorder, panic attacks, globus hystericus, vocal cord dysfunction, scombroid poisoning, vasoactive amine intolerance, carcinoid syndrome and phaeochromocytoma. Acute treatment of IA is the same as for other forms of anaphylaxis. Long-term management is individualized and dictated by frequency and severity of symptoms and involves treatment with H1 and H2 receptor blockers, leukotriene receptor antagonist and consideration for prolonged reducing courses of oral corticosteroids. Patients should possess an epinephrine autoinjector with an anaphylaxis self-management plan. There are anecdotal reports regarding the use of omalizumab. For reasons that remain unclear, the prognosis of IA is generally favourable with appropriate treatment and patient education. If remission cannot be achieved, the diagnosis should be reconsidered.

Differential Diagnosis of Asthma

Asthma is one of the most common chronic syndromes worldwide (Moorman et al., Vital Health Stat 3(35), 2012). It is not a diagnosis but a clinical syndrome based on a constellation of signs and symptoms (Li et al., Ann Allergy Asthma Immunol 81:415–420(IIa), 1998). The classic symptoms of asthma include chest tightness, wheeze, cough, and dyspnea (Moorman et al., Vital Health Stat 3(35), 2012). The term asthma encompasses a spectrum of pulmonary diseases sharing the hallmark of reversible airway obstruction and can be classified as allergic or non-allergic (Löwhagen, J Asthma. 52(6):538–44, 2015). Asthma designated allergic is due to an immunoglobulin E (IgE)-mediated process, but as noted not all asthma is allergic in etiology (Romanet-Manent et al., Allergy 57:607–13, 2002). The differential diagnosis for asthma is broad and requires a detailed history with supportive pulmonary function tests to be properly diagnosed.

A case series: Association of anaphylaxis with a significant decrease in platelet levels and possible secondary risk of thrombosis

Introduction

Anaphylaxis is a life threatening systemic inflammatory process that share mediators involved in the coagulation cascade. Platelet activating factor, known to increase platelet aggregation, has also been implicated as an important mediator of anaphylaxis. Although other inflammatory reactions are associated with an increased risk of thrombosis, anaphylaxis is currently not reported as one of them. Furthermore the role platelets may have in the perianaphylaxis period is not well understood. We here in present a retrospective case series of three patients that had platelet aberrations suggestive of PAF involvement and clinically significant thrombosis in close relationship with anaphylaxis.

Objective

To investigate platelet response before and after anaphylaxis and indirect observation evidence of platelet activating factors involvement with possible increased risk of thrombosis.

Methods

A retrospective investigation into medical records including medication administrations times, laboratory, and radiology results. Platelet levels pre‐ and post‐ anaphylaxis were statistically analyzed.

Results

Case 1, a 44 year old man had an anaphylactic reaction shortly after envenomation and subsequently suffered an acute infarction with thrombus in a cerebral artery. Case 2 is a 49 year old man with idiopathic anaphylaxis who developed a deep vein thrombosis after a protracted anaphylaxis event. Case 3 involved an 18 year old female with acute myeloid leukemia was found to have a thrombus in the celiac trunk following anaphylaxis. A paired two‐tailed Wilcoxon test on the subjects pre and post anaphylactic platelet levels resulted in a overall P < 0.0001.

Conclusions and Clinical Relevance

These three cases illustrate the potential role platelets may have in anaphylaxis and possible increased secondary risk for the development of thrombosis. Larger studies are required to determine incidence and risk factors for blood clots following anaphylaxis in order to provide management or screening recommendations.

Anaphylaxis with delayed appearance of skin manifestations during general anesthesia: two case reports

Background

Anaphylaxis is difficult to diagnose in the absence of skin or mucosal signs and symptoms. We report two cases of anaphylaxis under general anesthesia, in which the initial presentation was in the form of respiratory signs, followed by skin manifestations 10–15 min later. Diagnosis of anaphylaxis was delayed because skin symptoms were absent early on in the presentation.

Case presentation

In the first case, a 23-year-old male patient with jaw deformity was scheduled to undergo maxillary alveolar osteotomy. After intubation, auscultation indicated a sudden decrease in breath sounds, together with severe hypotension. Approximately 10 min later, flushing of the skin and urticaria on the thigh appeared and spread widely throughout the body. In the second case, a 21-year-old female patient with jaw deformity was scheduled to undergo maxillomandibular osteotomy. Twenty minutes after the start of dextran infusion, her lungs suddenly became difficult to ventilate, and oxygen saturation decreased to 90%. Approximately 15 min later, flushing of the skin and urticaria were observed.

Conclusion

In both cases, there was a time lag between the appearance of respiratory and skin symptoms, which resulted in a delay in the diagnosis, and hence, treatment of anaphylaxis. Our experience highlights the fact that it is difficult to diagnose anaphylaxis under general anesthesia.

Idiopathic Anaphylaxis

Idiopathic anaphylaxis is a rare life-threatening disorder with symptoms similar to other forms of anaphylaxis. There is lack of a robust evidence base underpinning the treatment of anaphylaxis and even less so for idiopathic anaphylaxis. Much of the evidence therefore comes from relatively small case series and expert opinion. Idiopathic anaphylaxis is a diagnosis of exclusion, requiring a thorough history and careful diagnostic work-up investigating possible triggers and underlying predisposing factors. Key diagnostic tests include skin-prick testing, tests for specific-IgE, component-resolved diagnostics, and in some cases for allergen challenge tests. Other recognized causes of anaphylaxis, such as foods, medications, insect stings, latex, and exercise, should all be considered, as should differential diagnoses such as asthma. While the cause of idiopathic anaphylaxis remains unknown, prompt treatment with intramuscular epinephrine (adrenaline) administered into the anterolateral aspect of the thigh is associated with good prognosis. There may also be a role for H1-antihistamines and corticosteroids as second-line agents. Patients need to be carefully monitored for signs of deterioration and/or a possible protracted or biphasic reaction. Patients with frequent episodes of anaphylaxis (e.g., six or more episodes/year) should be considered for preventive therapy, which may include corticosteroids, H1- and H2-antihistamines, and, in some cases, mast cell stabilizers such as ketotifen. Alternative immune-suppressants (e.g., methotrexate) and anti-IgE may rarely also need to be considered. In many cases, the frequency of anaphylaxis declines such that regular use of corticosteroids can be discontinued after 9–12 months. Pediatric patients should be treated with similar regimens as adults, but with appropriate dose adjustments. Patients should carry their self-injectable epinephrine and other emergency medications at all times in order to deal with emergency situations.

Risk Factor Analysis of Anaphylactic Reactions in Patients With Systemic Mastocytosis

BACKGROUND

Systemic mastocytosis (SM) is a rare disorder of abnormal mast cells in at least 1 extracutaneous organ/tissue. Anaphylaxis is an acute, severe systemic hypersensitivity reaction, and a strong association between SM and anaphylaxis has been shown. However, not all patients with SM experience anaphylaxis. Presently, there are no predictive markers to discriminate patients with SM at high risk of anaphylaxis from those at low risk.

OBJECTIVE

This study sought to determine risk factors for the occurrence of anaphylaxis in patients with SM.

METHODS

A cross-sectional study was conducted in 122 consecutive adult patients with SM admitted to the Mastocytosis Center at Karolinska University Hospital. All patients underwent medical evaluation, including bone marrow biopsy and a thorough allergy workup. To determine risk factors, study subjects were categorized into 2 groups according to the presence (n = 55) or absence (n = 67) of anaphylaxis and compared for their demographic, clinical, and biochemical characteristics.

RESULTS

Patients with SM with anaphylaxis had less frequent presence of mastocytosis in the skin (P < .001), more atopic predisposition (P = .021), higher total IgE levels (P < .001), and lower baseline tryptase levels (27 ng/mL vs 42 ng/mL; P = .024) compared with patients with SM without anaphylaxis.

CONCLUSIONS

Patients with SM with anaphylaxis display unique clinical and laboratory features. Hence, a risk analysis tool that is capable of discriminating patients with SM at high risk of anaphylaxis from those at low risk with 86% sensitivity was developed by using the variables male sex, absence of mastocytosis in the skin, presence of atopy, IgE levels of 15 kU/L or more, and baseline tryptase levels of less than 40 ng/mL.

Epidemiology of anaphylaxis

Knowledge about the epidemiology of anaphylaxis is based on data from various sources: clinical practice, large secondary clinical and administrative databases of primary care or hospitalized patients, and recent surveys with representative samples of the general population. As several similar results are often reported in several publications and populations, such findings are highly like to be robust. One such finding is that the incidence and prevalence of anaphylaxis are higher than previously thought. Publications from the last 5 years reveal an incidence of between 50 and 112 episodes per 100 000 person-years; estimated prevalence is 0.3-5.1% depending on the rigour of the definitions used. Figures are higher in children, especially those aged 0-4 years. Publications from various geographical areas based on clinical and administrative data on hospitalized patients suggest that the frequency of admissions due to anaphylaxis has increased (5-7-fold in the last 10-15 years). Other publications point to a geographic gradient in the incidence of anaphylaxis, with higher frequencies recorded in areas with few hours of sunlight. However, these trends could be the result of factors other than a real change in the incidence of anaphylaxis, such as changes in disease coding and in the care provided. Based on data from the records of voluntary declarations of death by physicians and from large national databases, death from anaphylaxis remains very infrequent and stands at 0.35-1.06 deaths per million people per year, with no increases observed in the last 10-15 years. Although anaphylaxis can be fatal, recurrence of anaphylaxis--especially that associated with atopic diseases and hymenoptera stings--affects 26.5-54% of patients.

Management and Prevention of Anaphylaxis

Anaphylaxis prevalence has increased within the last few years. This may be due to a marked increase in allergic sensitization to foods especially in the pediatric population, as well as to an increase in outdoor recreational habits and the availability of new biologic medications.  Furthermore, guidelines for the diagnosis of anaphylaxis have been published, thus facilitating the recognition of this disorder. Diagnosis of anaphylaxis is mainly based on history and clinical criteria of organ system involvement. The serum tryptase assay is now commercially available and may be a helpful diagnostic tool in certain clinical situations involving hypotension, but not in the context of food-induced anaphylaxis. Treatment of anaphylaxis mainly involves the use of epinephrine as a first line medication for severe manifestations followed by  symptomatic management of specific  symptoms, such as antihistamines for urticaria and albuterol for wheezing. Although commonly practiced, treatment with systemic corticosteroids  is not supported by evidence-based literature. Observation in a medical facility for 4-6 hours is recommended to monitor for late phase reactions, although these rarely occur. Education is an essential component of management of a patient with a previous history of anaphylaxis, emphasizing early use of epinephrine and providing a written action plan. Referral to a board-certified allergist/immunologist is recommended to determine  the cause of the anaphylaxis as well as to rule out other potential conditions. In this review, our main focus will be on the treatment and prevention of anaphylaxis while providing our readers with a brief introduction to the diagnosis of anaphylaxis, its prevalence and its most common causes.

Mast cell activation syndromes presenting as anaphylaxis

Anaphylaxis results from severe systemic mast cell activation. In addition to IgE-mediated and physical triggers, it may occur with a clonal mast cell disease and in an idiopathic fashion without clear provoking factors. Disorders of mast cell activation are classified into primary (clonal), secondary, and idiopathic. Mast cell activation syndrome (MCAS) is a multisystem disorder characterized by objective documentation of elevated mast cell mediators during attacks and a favorable response to antimediator therapy. It should be considered in the differential diagnosis of patients presenting with recurrent anaphylaxis without a clear cause. This article discusses the diagnosis of MCAS.

The presence of mast cell clonality in patients with unexplained anaphylaxis

BACKGROUND

The mechanisms by which mast cells in patients with unexplained anaphylaxis (UEA) are triggered remain elusive. Onset of episodes is unpredictable and often recurrent. The substantial overlap between the clinical manifestations of UEA and clonal mast cell disorders (CMD) suggests an association between these rare disorders. The two forms of CMD characterized to date are systemic mastocytosis (SM) and monoclonal mast cell activation syndrome (MMAS).

OBJECTIVE

To examine the hypothesis that the pathogenesis of UEA reflects the presence of aberrant subpopulations of mast cells.

METHODS

Thirty (14 men, 16 women) patients (≥ 18 years) suffering from UEA and with no signs of cutaneous mastocytosis were recruited. Patients underwent an initial complete allergy work-up to confirm the diagnosis of UEA. Level of baseline serum tryptase (sBT) and total IgE were determined. In addition, a bone marrow examination was performed on all 30 patients to investigate possible underlying CMD.

RESULTS

Fourteen (47%) of our cases (nine men, five women) were diagnosed with CMD: 10 with SM and four with MMAS. Four of the 10 patients with SM had mast cell aggregates in their bone marrow. All patients with SM exhibited a sBT level > 11.4 ng/mL, whereas this level was elevated in only two of those with MMAS and four with UAE but not diagnosed with CMD. Total IgE levels were lower in the group of patients with CMD (P < 0.03).

CONCLUSION AND CLINICAL RELEVANCE

The pathogenic mechanism underlying UEA could be explained by the presence of immunophenotypically aberrant mast cells with clonal markers in 47% of our subjects, indicating that clonal mast cell disorders are present in a substantial subset of these patients. Thus, the presence of CMD should be considered in patients with UEA if they have an elevated level of sBT (≥ 11.4 ng/mL) and cardiovascular symptoms such as syncope.

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.

Heterogeneity in presentation and treatment of catamenial anaphylaxis

BACKGROUND

Few reports have documented the uncommon association of the female menstrual cycle with anaphylaxis, an entity known as cyclic or catamenial anaphylaxis.

OBJECTIVE

To examine cases of perimenstrual anaphylaxis, focusing on differences in presentation and response to treatment, in the hopes of enriching the description of this rare entity.

METHODS

A cohort of 8 women with catamenial anaphylaxis were identified and retrospectively compared with regard to age at onset, organ involvement, diagnostic studies, and response to therapy.

RESULTS

The median age at onset was 34 years (range, 14-40 years), and the median number of perimenstrual anaphylactic episodes at presentation was 10 per patient (range, 4-24 per patient). Most had cutaneous and gastrointestinal symptoms. The results of extensive investigations for anaphylactic triggers were negative, and masquerading conditions, such as carcinoid syndrome, pheochromocytoma, and systemic mastocytosis, were ruled out in all patients. Skin test results for progesterone were negative in all but 1 of 4 patients tested. None had elevated total serum IgE levels. Response to suppressive treatments regimens varied considerably, but none treated with high-dose systemic steroids had improvement. Similarly, ketotifen, celecoxib, rofecoxib, and oral contraceptives failed to control the anaphylactic reactions. Although antihistamines failed in 7 patients, 1 had improvement. Others responded to leuprolide, medroxyprogesterone, or salpingo-oophorectomy.

CONCLUSION

Whether the mechanism causing cyclical anaphylaxis may involve hypersensitivity to progesterone or prostaglandins, the variable response to suppressive medications in these cases suggests that catamenial anaphylaxis is a heterogeneous disorder in which a number of mechanisms and mediators may play a role. It is an emergent and probably underrecognized entity in the medical literature.

Anaphylaxis in a tertiary adult allergy clinic: a retrospective review of 516 patients

BACKGROUND

Anaphylaxis is a life-threatening acute allergic reaction that can occur at any age.

OBJECTIVE

To determine the frequency, triggering factors, and clinical features of anaphylaxis among adult patients who were referred to a tertiary health care facility.

METHODS

A retrospective medical chart review was performed including all patients referred to the outpatient clinic of the adult allergy department in our university hospital between January 1, 2008 and December 30, 2011 to determine cases involving anaphylaxis.

RESULTS

A total of 516 (2.11%) patients among 24,443 admissions were diagnosed with anaphylaxis. Although the second highest frequency of anaphylaxis cases took place in 2008, a gradual rise in the frequency was determined from 2009 to 2011. Drugs (90.7%) were the most frequent cause, followed by Hymenoptera stings (5.4%), foods (1.6%), latex (0.4%), and exercise (0.2%) respectively. The clinical manifestations during anaphylaxis reported by patients were cutaneous (n = 292, 56.6%), respiratory (n = 253, 49%), cardiovascular (n = 212, 41%), neuropsychiatric (n = 60, 11.6%), and gastrointestinal (n = 52, 10.1%), respectively. Approximately one fifth of the patients received epinephrine, whereas 43% of patients did not receive epinephrine during their treatment in the emergency room. An epinephrine auto-injector was prescribed to 42 patients (8.1%).

CONCLUSION

In this study, the second pattern of National Institute of Allergy and Infectious Disease (NIAID) and the Food Allergy and Anaphylaxis Network (FAAN) diagnostic criteria for anaphylaxis predominated among adult patients. Drugs were the leading triggering factor, followed by Hymenoptera stings, foods, latex, and exercise, respectively. Atopy, asthma, and allergic rhinitis were rarely detected.

Anaphylaxis in Israel: experience with 92 hospitalized children

Little is known about the courses, causes, and clinical features of anaphylaxis in children outside the USA and Europe. Our objective was to evaluate the events of anaphylaxis in children admitted to the Schneider Children's Medical Center of Israel, a major tertiary facility, over a 12-year period. Ninety-two children with anaphylaxis (50 boys, 42 girls) aged 14 days to 18 yr (mean, 7.4 yr) were hospitalized during the study period. The event occurred at home in 52 children (56%), in a medical institution in 24 (26%), outdoors in 13 (15%), at school in 2 (2%), and in an unspecified location in 1 (1%). The main causes were foods (43%), mainly milk and nuts, medications (22%), and hymenoptera venom (11%); in five children, anaphylaxis occurred during general anesthesia, and in 5, the causative agent could not be determined. Food-induced anaphylaxis tended to occur in younger children. Forty-eight children (52%) had a history of atopy (mainly asthma). Hospital treatment consisted of corticosteroids (85%), antihistamines (75%), epinephrine (72%), and β2 agonists (42%). Seven patients were admitted to intensive care units. There were no fatalities. EpiPen was used by only one of the 16 patients with more than one episode of anaphylaxis, indicating that patient and parent education in the application of the EpiPen needs to be improved.

Anaphylaxis and mast cell disease: what is the risk?

Mastocytosis is a proliferative disorder of the hematopoietic mast cell progenitor that results from expansion of a clone carrying the D816V c-kit mutation. Based on the dramatic increase in incidence of anaphylaxis in patients with mastocytosis, recent studies analyzed the presence of clonal mast cell markers, including D816V c-kit mutation, in patients with recurrent IgE- and non-IgE-mediated anaphylaxis. These studies demonstrated the presence of an aberrant mast cell clone in a significant proportion of patients with unexplained anaphylaxis, or anaphylaxis due to hymenoptera venom. Clonal mast cell disease should be suspected in particular in patients presenting with profound cardiovascular manifestations such as hypotension and syncope in the absence of urticaria.

The diagnosis and management of anaphylaxis practice parameter: 2010 update

These parameters were developed by the Joint Task Force on Practice Parameters, representing the American Academy of Allergy, Asthma & Immunology (AAAAI); the American College of Allergy, Asthma & Immunology (ACAAI); and the Joint Council of Allergy, Asthma and Immunology. The AAAAI and the ACAAI have jointly accepted responsibility for establishing "The Diagnosis and Management of Anaphylaxis Practice Parameter: 2010 Update." This is a complete and comprehensive document at the current time. The medical environment is a changing environment, and not all recommendations will be appropriate for all patients. Because this document incorporated the efforts of many participants, no single individual, including those who served on the Joint Task Force, is authorized to provide an official AAAAI or ACAAI interpretation of these practice parameters. Any request for information about or an interpretation of these practice parameters by the AAAAI or ACAAI should be directed to the Executive Offices of the AAAAI, the ACAAI, or the Joint Council of Allergy, Asthma and Immunology. These parameters are not designed for use by pharmaceutical companies in drug promotion.

Anaphylactic reactions on the beach: a cause for concern?

BACKGROUND

The commonest causes of anaphylaxis include hymenoptera bites, high-risk food, exercise, and jellyfish bites and may often be encountered on the beach. Therefore, millions of visitors at popular touristic locations are exposed to increased risk of anaphylactic reactions every year. At least 35 cases of acute allergic reactions requiring medical attention took place on the beaches of Crete, Greece during the previous summer.

OBJECTIVE

To evaluate the level of training of lifeguards working on the beaches of the island of Crete, Greece, with regard to emergency management of anaphylaxis as well as to assess the sufficiency of medical equipment that lifeguards possess to treat an anaphylactic reaction.

METHODS

A questionnaire was prepared by the authors and administered to 50 lifeguards working on various beaches of Crete. Queries included the definition of anaphylaxis, proper medical treatment, and the existence or not and composition of an emergency kit with regard to the management of acute allergic reactions.

RESULTS

Our series consisted of 50 lifeguards, 39 (78%) male and 11 female (22%). Although 41 (80%) lifeguards were aware of an acceptable definition of anaphylaxis, no one knew that epinephrine is the first-choice treatment, and 32 (60%) lifeguards replied that steroids should be used for emergency treatment. Additionally, no one possessed an emergency kit that would qualify for management of acute allergic reactions.

CONCLUSIONS

The beach should be considered as a high-risk place for the appearance of anaphylactic reactions. Lifeguards who would be the first trained personnel to encounter this condition should be sufficiently trained and equipped for emergency treatment. Our department is currently introducing a training program to local authorities for the proper training and equipping of lifeguards in the island of Crete.

Mastocytosis and allergy

PURPOSE OF REVIEW

To illustrate features of allergy in mastocytosis.

RECENT FINDINGS

The rates of atopy in patients with mastocytosis have generally been found to be similar to those of the normal population, although the incidence of anaphylaxis is much higher in mastocytosis. Introduction of objective pathologic criteria by the WHO for the diagnosis of mastocytosis has greatly facilitated the workup of patients with suspected mastocytosis, and has led to identification of mast cell disease in a subset of patients with anaphylaxis. There is increasing evidence that an activating c-kit mutation (D816V) exists in a subset of patients with recurrent mast cell activation symptoms who have normal-appearing bone marrow biopsies in routine evaluations without skin lesions. The genetic deficiency of alpha tryptase has not been found to influence serum tryptase levels in patients with mastocytosis.

SUMMARY

Pathologic mast cell activation is a key finding in both allergic diseases and mastocytosis, albeit caused by entirely different mechanisms. Mastocytosis should be suspected in patients with recurrent anaphylaxis, who present with syncopal or near-syncopal episodes without associated hives or angioedema.

Navigating the updated anaphylaxis parameters

: Anaphylaxis, an acute and potentially lethal multi-system clinical syndrome resulting from the sudden, systemic degranulation of mast cells and basophils, occurs in a variety of clinical scenarios and is almost unavoidable inmedical practice. Healthcare professionalsmust be able to recognize its features, treat an episode promptly and appropriately, and be able to provide recommendations to prevent future episodes. Epinephrine, administered immediately, is the drug of choice for acute anaphylaxis. The discussion provides an overview of one set of evidence-based and consensus parameters for the diagnosis and management of anaphylaxis.

Idiopathic Anaphylaxis

Idiopathic anaphylaxis is a prednisone-responsive condition without external cause, but it can coexist with food-, medication-, or exercise-induced anaphylaxis. Mast cell activation may occur at night or after foods that have been eaten with impunity many times previously. Idiopathic anaphylaxis can be classified into frequent (if there are six or more episodes per year or two episodes in the last 2 months) or infrequent (if episodes occur less often). Idiopathic anaphylaxis-generalized consists of urticaria or angioedema associated with severe respiratory distress, syncope or hypotension, and gastrointestinal symptoms. Idiopathic anaphylaxis-angioedema consists of massive tongue enlargement or severe pharyngeal or laryngeal swelling with urticaria or peripheral angioedema. The differential diagnosis of idiopathic anaphylaxis is reviewed, and treatment approaches are presented.

Anaphylactic and anaphylactoid causes of angioedema

Anaphylactic and anaphylactoid (pseudoallergic) reactions can be expected to occur with greater frequency as the number of immunomodulators are employed. The immune system will become sensitized to these new therapeutic agents or there may be first-dose reactions depending on the pathogenetic mechanism involved. Physicians should review their office or procedure room emergency preparedness protocols and medications. The lack of penicillin major and minor determinants for penicillin testing has made management of penicillin and cephalosporin allergic patients more complicated. In the absence of skin-testing materials, test-challenges will be necessary and performed with less comfort because of not knowing the current level of immunologic sensitization to penicillin. The indication for readministration of any incriminated medication/therapeutic agent should be reviewed. Often, there are not suitable alternatives. Various approaches have been presented to permit safer readministration of essential medications or diagnostic agents to prevent episodes of anaphylaxis or upper airway angioedema.

Anaphylaxis presentations to an emergency department in Hong Kong: incidence and predictors of biphasic reactions

We describe the epidemiology, clinical features and management of anaphylaxis in a population in Hong Kong, including the features associated with progression to biphasic reactions and the nature of these reactions. A retrospective review was undertaken of patients of all age groups, presenting consecutively to the resuscitation room of a large Hong Kong emergency department with the diagnosis of anaphylaxis, from March 1999 to February 2003. There were 282 patients included. Median age was 28 years, with 59% male. A precipitant was identified in 89%, with 19% of patients claiming a known allergy to the precipitant. Seafood was responsible for 71% of all food-related reactions. More patients reacted to nonsteroidal anti-inflammatory drugs rather than antibiotics. Cutaneous features were present in 79%, and 12% presented with hypotension. Ninety-five percent received H1 antagonist, and 67% received epinephrine. Biphasic reactions were reported in 15 (5.3%) cases with 20% of these patients having unstable vital signs. The mean time from treatment to onset of biphasic reaction was 8 h (range 1-23). Patients with respiratory features on initial presentation were less likely to develop biphasic reactions. It is concluded that prolonged observation of patients with anaphylaxis is important, because of the risk of biphasic reactions. Better education could prevent recurrent anaphylaxis.

Epidemiology of anaphylaxis among children and adolescents enrolled in a health maintenance organization

BACKGROUND

There is little information about the incidence of anaphylaxis from all causes.

OBJECTIVE

The objects of this study were (1) to estimate the incidence of anaphylaxis; (2) to explore the range of diagnoses attributed to an anaphylactic episode; and (3) to describe the clinical features of anaphylaxis.

METHODS

The study population consisted of children and adolescents enrolled at a health maintenance organization. We identified potential episodes of anaphylaxis occurring between 1991 and 1997 from automated databases and reviewed the medical record to confirm the diagnosis. We reviewed all diagnoses specific for anaphylaxis (eg, ICD-9 995.0, anaphylactic shock) and sampled from among other related diagnoses (eg, ICD-9 995.3, allergy unspecified). Estimation of the incidence of provider-diagnosed anaphylaxis was based on cases confirmed from among the specific diagnosis codes. Description of the clinical features of anaphylaxis involved all confirmed cases regardless of diagnosis.

RESULTS

We identified 67 episodes of anaphylaxis among children with diagnosis codes specific for anaphylaxis (10.5 episodes per 100,000 person-years). There was no increase in incidence over time. Review of samples of diagnoses not specific for anaphylaxis yielded an additional 18 episodes. Among all identified episodes (n = 85), mucocutaneous and respiratory manifestations were the most common. Seventy-one percent of episodes were treated in the emergency department. Nine episodes (11%) resulted in hospitalization.

CONCLUSIONS

The incidence of anaphylaxis did not increase during these years. A majority of episodes were treated in the emergency department. Anaphylaxis in this population was frequently diagnosed as another related condition, and the basis and implications of diagnostic practices in this disorder warrant further exploration.

A current review of idiopathic anaphylaxis

PURPOSE OF REVIEW

Idiopathic anaphylaxis is a well established entity that can lead to unnecessary morbidity and costs if not diagnosed and managed properly. To ensure that more patients benefit from proper care, the medical community needs to be better informed of this rare disease.

RECENT FINDINGS

The classification and treatment of idiopathic anaphylaxis have been fine-tuned over the past 25 years without knowledge of the disease's underlying mechanism, despite much research dedicated towards this end. The observation that idiopathic anaphylaxis is a steroid-responsive disease has led to a more recent view that its underlying mechanism may be autoimmune in nature.

SUMMARY

Although the underlying pathogenesis of idiopathic anaphylaxis remains unknown, thousands of patients in the United States have been successfully treated with the currently recommended regimen of steroids and antihistamines. If diagnosed and treated properly, approximately 85% of patients will have a sustained remission after being tapered off corticosteroids.