Prevention of Anaphylaxis Episodes in Idiopathic Anaphylaxis by Omalizumab

INTRODUCTION

In 15-35 percent of patients with anaphylaxis, the triggering allergen cannot be found; therefore, a diagnosis of idiopathic anaphylaxis (IA) is made. We report on the outcomes in patients with IA treated with omalizumab.

METHODS

We included consequent omalizumab-treated IA adult patients treated with omalizumab 300 mg every 4 weeks.

RESULTS

Out of 7 patients, 6 were female, median age 40 years with the frequency of anaphylaxis episodes from 3 in 2 years to 5 in 4 months. Baseline tryptase ranged from 1.71 to 12.0 μg/L. An increase in tryptase during anaphylaxis was documented in 6 patients. Activating KIT p.D816V variant was detected in 2 patients. One patient also had hereditary alpha-tryptasemia (HαT). The duration of omalizumab treatment was 0.5-7.5 years. None of the patients have experienced an anaphylactic reaction since the start of treatment. Mild systemic reactions were reported in 6 patients (86%). The presence of underlying cMCD had no impact on the treatment outcome.

CONCLUSION

All patients in our study had complete responses to omalizumab. The presence of KIT p.D816V and HαT did not influence the response to omalizumab treatment.

Mental health problems associated with idiopathic anaphylaxis

BACKGROUND

Idiopathic Anaphylaxis (IA) is the most common anaphylactic syndrome in adults. Mental health problems associated with IA are not well recognised. We aimed to assess if patients diagnosed with IA were more likely to experience mental health problems compared to a normative Australian population. We additionally hypothesised that the number of anaphylactic episodes would correlate with symptoms of anxiety.

METHODS

A total of 34 patients with at least one episode of IA were recruited from an adult immunology clinic. Patients were recruited as part of a separate study evaluating alternative aetiologies in IA. Mental health problems were measured using the Depression, Anxiety and Stress Scale (DASS-21). An extension of the survey included questions specifically focused on the psychological impact of IA.

RESULTS

Compared to population norms, those with IA had significantly higher levels of mental health problems. Statistically significant DASS-21 scores were identified for depression 4.24 vs. 2.57 (p < 0.001), anxiety 4.76 vs. 1.74 (p < 0.012), stress 7.35 vs. 3.95 (p < 0.001) and total score 16.35 vs. 8.00 (p < 0.001). There was no association between two or more episodes of anaphylaxis and increased anxiety levels (β = 0.52, CI -2.59-3.62, p = 0.74).

CONCLUSIONS

This is the first paper to demonstrate that patients living with idiopathic anaphylaxis are more symptomatic for mental illness than those in the community. Screening for mental illness and referral for psychological support should be undertaken in people with IA.

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.

sCD14 and Intestinal Fatty Acid Binding Protein Are Elevated in the Serum of Patients With Idiopathic Anaphylaxis

BACKGROUND

Intestinal epithelial integrity compromise has been identified in gastrointestinal (GI), atopic, and autoimmune diseases.

OBJECTIVE

Episodes of idiopathic anaphylaxis (IA) are often accompanied by GI manifestations. We, therefore, sought to determine whether surrogate markers of GI permeability were aberrant in this patient population.

METHODS

Serum concentrations of zonulin, intestinal fatty acid binding protein (I-FABP), and soluble CD14 (sCD14) measured in 54 patients with IA were compared with concentrations in healthy controls (HCs); and correlated with clinical and laboratory parameters.

RESULTS

The I-FABP was elevated in sera of patients with IA compared with HCs (median 1,378.0 pg/mL vs 479.0 pg/mL, respectively; P < .001). The sCD14 was also elevated compared with HCs (median 2,017.0 ng/mL and 1,189.0 ng/mL, respectively; P < .001), whereas zonulin was comparable between patients with IA and HCs (median 49.6 ng/mL vs 52.4 ng/mL, respectively; P = .40). The I-FABP was elevated in patients with IA who experienced vomiting and/or diarrhea compared with patients with IA who did not (P = .0091).

CONCLUSIONS

The I-FABP and sCD14 are elevated in the serum of patients with IA. Elevations in these biomarkers of IA provides evidence that increased GI permeability, as is observed in other allergic conditions such as food allergy, is a common finding in those with IA and offers possible insight into the pathogenesis of this disease.

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.

Risk Factors and Characteristics of Biphasic Anaphylaxis

BACKGROUND

Anaphylaxis is an immediate hypersensitivity reaction. However, a biphasic course with the second onset of symptoms can occur hours after the initial phase. Little is known about the causes of biphasic anaphylaxis making the identification of patients at risk difficult.

OBJECTIVE

To identify factors predisposing for biphasic anaphylaxis for the better understanding of these reactions.

METHODS

Data from the Anaphylaxis Registry (from 11 countries) including 8736 patients with monophasic and 435 biphasic anaphylaxis were analyzed.

RESULTS

The rate of biphasic reactions in this large cohort was 4.7%. The identified risk factors were reaction severity (grade III/IV vs grade II: odds ratio [OR] = 1.34; 95% confidence interval [CI]: 1.1-1.62); multiorgan involvement; skin, gastrointestinal, severe respiratory, and cardiac symptoms; anaphylaxis caused by peanut/tree nut (OR = 1.78; 95% CI: 1.38-2.23) or an unknown elicitor (OR = 1.96; 95% CI: 1.41-2.72); exercise as a cofactor (OR = 1.44; 95% CI: 1.17-1.78); chronic urticaria as a comorbidity (OR = 2.12; 95% CI: 1.19-3.78); a prolonged interval between the contact with the elicitor and start of primary symptoms (OR for >30 vs <30 min: 1.38; 95% CI: 1.08-1.76); and antihistamine treatment (OR = 1.52; 95% CI: 1.14-2.02).

CONCLUSION

A biphasic course of anaphylaxis occurs more frequently in severely affected patients with multiorgan involvement. However, we identified multiple additional predictors, suggesting that the pathogenesis of biphasic reactions is more complex than being a rebound of a severe primary reaction.

Insect Sting Anaphylaxis-Or Mastocytosis-Or Something Else?

Insect sting anaphylaxis and mast cell disorders are intertwined in a specific and unusual way. There may be specific subsets of clonal mast cell disorders that are predisposed to sting anaphylaxis. The clinical characteristics of the sting reactions should raise suspicion of underlying mastocytosis (eg, hypotension without hives especially in a male). A baseline serum tryptase level is helpful in the evaluation of patients with insect sting anaphylaxis because it correlates with important risks for these patients, and they have a high frequency of abnormally elevated baseline levels. Elevated baseline serum tryptase level has been reported to correlate with clonal mast cell disease in patients with insect sting anaphylaxis but may also indicate one of several possible underlying syndromes, including mast cell activation syndrome (MCAS), familial hypertryptasemia, and idiopathic anaphylaxis. There is some overlap in these conditions, so it is important to evaluate the clinical pattern at presentation as well as laboratory markers, and to consider bone marrow biopsy to make a final and specific diagnosis of clonal mast cell disease. The presence of venom-IgE does not prove that the patient's previous sting reactions were IgE-mediated, but even low levels of venom-IgE in patients with mastocytosis predispose to severe sting anaphylaxis. Evaluation of all these possible factors will affect the recommendation for venom immunotherapy.

Mast Cell Activation: When the Whole Is Greater than the Sum of Its Parts

Mast cell activation syndrome (MCAS) is a heterogeneous and rare disorder with episodic and severe activation of mast cells. Because symptoms of mast cell activation are nonspecific, it is important to base the diagnosis on best available clinical and scientific evidence, and not make it one of exclusion. MCAS, much like the mast cell itself, as a whole is greater than the sum of its proposed diagnostic criteria. When each component is considered in isolation, criteria can seem nonspecific, and thus, a broad constellation of symptoms can be attributed to MCAS when they may be due to other disease processes.

Emergency Management of Anaphylaxis Due to an Unknown Trigger: An 8-Year Follow-Up Study in Canada

BACKGROUND

Anaphylaxis due to unknown trigger (AUT) is anaphylaxis not explained by a proved or presumptive cause or stimulus at the time of the reaction. Research describing the management and follow-up of AUT is limited.

OBJECTIVE

To assess and compare the demographic and clinical characteristics and the management of adult and pediatric AUT cases across Canada.

METHODS

Participants were identified between 2011 and 2018 in emergency departments at 8 centers across Canada as part of the Cross-Canada Anaphylaxis Registry. A standardized form documenting the reaction and management in children and adults was completed. Patients were contacted for follow-up to determine assessment by an allergist.

RESULTS

A total of 295 AUT cases (7.5%) were recruited among 3,922 cases of anaphylaxis. In the prehospital setting, children (adjusted odds ratio [aOR], 1.20; 95% CI, 1.05-1.37) and those with a known food allergy (aOR, 1.14; 95% CI, 1.02-1.28) were more likely to receive treatment with epinephrine. Children were also more likely to be assessed by an allergist after their reaction (aOR, 1.43; 95% CI, 1.13-1.81) and were more likely to have an identified trigger for their reaction (aOR, 1.35; 95% CI, 1.07-1.70). Among patients contacted for follow-up, food was identified as the cause of reaction in 11 of 76 patients. A new food allergy was diagnosed in 4 patients (2 children and 2 adults).

CONCLUSIONS

Our findings highlight important differences between management and follow-up of adult and pediatric AUT cases. It is crucial to follow up all cases of AUT and establish appropriate treatment and management guidelines.

International consensus on (ICON) anaphylaxis

ICON: Anaphylaxis provides a unique perspective on the principal evidence-based anaphylaxis guidelines developed and published independently from 2010 through 2014 by four allergy/immunology organizations. These guidelines concur with regard to the clinical features that indicate a likely diagnosis of anaphylaxis -- a life-threatening generalized or systemic allergic or hypersensitivity reaction. They also concur about prompt initial treatment with intramuscular injection of epinephrine (adrenaline) in the mid-outer thigh, positioning the patient supine (semi-reclining if dyspneic or vomiting), calling for help, and when indicated, providing supplemental oxygen, intravenous fluid resuscitation and cardiopulmonary resuscitation, along with concomitant monitoring of vital signs and oxygenation. Additionally, they concur that H1-antihistamines, H2-antihistamines, and glucocorticoids are not initial medications of choice. For self-management of patients at risk of anaphylaxis in community settings, they recommend carrying epinephrine auto-injectors and personalized emergency action plans, as well as follow-up with a physician (ideally an allergy/immunology specialist) to help prevent anaphylaxis recurrences. ICON: Anaphylaxis describes unmet needs in anaphylaxis, noting that although epinephrine in 1 mg/mL ampules is available worldwide, other essentials, including supplemental oxygen, intravenous fluid resuscitation, and epinephrine auto-injectors are not universally available. ICON: Anaphylaxis proposes a comprehensive international research agenda that calls for additional prospective studies of anaphylaxis epidemiology, patient risk factors and co-factors, triggers, clinical criteria for diagnosis, randomized controlled trials of therapeutic interventions, and measures to prevent anaphylaxis recurrences. It also calls for facilitation of global collaborations in anaphylaxis research. IN ADDITION TO CONFIRMING THE ALIGNMENT OF MAJOR ANAPHYLAXIS GUIDELINES, ICON: Anaphylaxis adds value by including summary tables and citing 130 key references. It is published as an information resource about anaphylaxis for worldwide use by healthcare professionals, academics, policy-makers, patients, caregivers, and the public.

A case of idiopathic anaphylaxis followed by acute liver injury

Idiopathic anaphylaxis is characterized by recurrent anaphylaxis without a known trigger. The coexistence of acute liver injury with idiopathic anaphylaxis is rare, even in cases of severe anaphylaxis such as shock. An unusual case involving repeated episodes of anaphylactic shock accompanied by acute liver injury is described here. A 36-year-old woman who experienced anaphylaxis due to an unknown cause was referred to our hospital because of marked elevations in her liver enzyme levels. After a thorough evaluation to determine the cause of the acute liver injury, viral infection, drug use, and autoimmune hepatitis were excluded. The episodes were accompanied by elevated liver enzymes, which suggested that this was a case of anaphylaxis followed by acute liver injury. The patient will have to use self-injectable epinephrine to prevent future hepatic failure.