Multiple Chemical Sensitivity/Idiopathic Environmental Intolerance: A Practical Approach to Diagnosis and Management.

Patients with multiple chemical sensitivity, now called idiopathic environmental intolerance, frequently present to clinical immunologists and allergists for diagnosis and treatment. Patients report a plethora of respiratory and multisystem problems attributed to a wide variety of unrelated, otherwise non-noxious, triggers. They may go to extreme, often seemingly bizarre lengths to avoid contact with everyday exposures and may become housebound, unable to work or function socially. Often beginning with exposure to odors, triggers can multiply to involve foods, clothing, medications, and even electromagnetic radiation. The condition cannot be explained by IgE-mediated or other immune processes, and clinical immunologists and allergists may feel unprepared to care for such patients. In this article, a paradigm to understand the probable mechanisms underlying this condition and a practical approach to diagnosis and management will be presented.

Hereditary Angioedema in Pregnancy.

IMPORTANCE: Hereditary angioedema is a rare disease of potentially life-threatening attacks of angioedema that can affect patients of all ages, including women of childbearing age. Pregnancy can affect the course of the disease and the choice of treatment used. It is important for the care providers to recognize this disease and understand its mechanism in order to provide appropriate care for the patients. OBJECTIVE: The goal of this article is to provide an overview of hereditary angioedema and guideline for management of pregnant patients with hereditary angioedema. EVIDENCE ACQUISITION: A search of the available English language literature was performed on PubMed and Ovid MEDLINE using the key words hereditary angioedema and pregnancy. Additional articles were selected from the reference lists of the reviewed articles. RESULTS: The data for hereditary angioedema in pregnant patients come from observational studies, case reports, retrospective reviews, and questionnaires. The course of hereditary angioedema can be variable between different patients and pregnancies. Plasma-derived C1 inhibitor concentrate is both safe and effective as treatment for attacks and as preventive therapy in pregnancy. With proper recognition, understanding of the disease, and appropriate medical management, most patients will undergo successful pregnancy and delivery. CONCLUSIONS AND RELEVANCE: Clinicians should maintain high suspicion for this disease when patients present with recurrent episodes of angioedema without urticaria or severe abdominal pains of unclear etiology. Treatment plans during pregnancy and delivery should be individualized, and the patient's care should be shared by a clinician experienced in the management of this disease.

Measurement of Bradykinin Formation and Degradation in Blood Plasma: Relevance for Acquired Angioedema Associated With Angiotensin Converting Enzyme Inhibition and for Hereditary Angioedema Due to Factor XII or Plasminogen Gene Variants.

Bradykinin (BK)-mediated angioedema (AE) states are rare acquired or hereditary conditions involving localized edema of the subcutaneous and submucosal tissues. Citrated plasma from healthy volunteers or patients with hereditary angioedema (HAE) with normal level of C1-inhibitor (C1-INH) was used to investigate pathways of BK formation and breakdown relevant to AE physiopathology. The half-life of BK (100 nM) added to normal plasma was 34 s, a value that was increased ~12-fold when the angiotensin converting enzyme (ACE) inhibitor enalaprilat (130 nM) was added (enzyme immunoassay measurements). The BK half-life was similarly increased ~5-fold following 2 daily oral doses of enalapril maleate in healthy volunteers, finding of possible relevance for the most common form of drug-associated AE. We also addressed the kinetics of immunoreactive BK (iBK) formation and decline, spontaneous or under three standardized stimuli: tissue kallikrein (KLK-1), the particulate material Kontact-APTT™ and tissue plasminogen activator (tPA). Relative to controls, iBK production was rapid (10-20 min) and very intense in response to tPA in plasma of female heterozygotes for variants in gene F12 coding for factor XII (FXII) (p.Thr328Lys, 9 patients; p.Thr328Arg, one). An increased response to Kontact-APTT™ and an early tPA-induced cleavage of anomalous FXII (immunoblots) were also observed. Biotechnological inhibitors showed that the early response to tPA was dependent on plasmin, FXIIa and plasma kallikrein. Results from post-menopausal and pre-menopausal women with HAE-FXII were indistinguishable. The iBK production profiles in seven patients with the plasminogen p.Lys330Glu variant (HAE-PLG) did not significantly differ from those of controls, except for an unexpected, rapid and lanadelumab-resistant potentiation of KLK-1 effect. This enzyme did not cleave plasminogen or factor XII, suggesting a possible idiosyncratic interaction of the plasminogen pathogenic variant with KLK-1 activity. KLK-1 abounds in salivary glands and human saliva, hypothetically correlating with the clinical presentation of HAE-PLG that includes the swelling of the tongue, lips and contiguous throat tissues. Samples from HAE patients with normal C1-INH levels and F12 gene did not produce excessive iBK in response to stimuli. The ex vivo approach provides physiopathological insight into AE states and supports the heterogeneous physiopathology of HAE with normal C1-INH.

Improving the diagnosis and treatment of CRPS: insights from a clinical immunologist's personal experience with an underrecognized neuroinflammatory disorder.

Complex regional pain syndrome is a neuroinflammatory condition associated with overactive glial cells that can be challenging to diagnose and treat. Early recognition and treatment are thought to be critical for good outcomes, yet many patients experience a delay in diagnosis and have difficulty accessing expert medical care. While there are no universally effective treatments, there are several promising new therapies, but these are not widely available. Some of the specific barriers to diagnosis and treatment are reviewed, with suggestions as to how they might be eliminated, leading to better care for all patients with CRPS.

Hereditary angioedema with normal C1 inhibitor function: consensus of an international expert panel.

A new form of hereditary angioedema (HAE) with normal C1 inhibitor (C1INH) was first described in 2000. The lack of clear diagnostic criteria, the heterogeneity among affected patients, and the varying names given to this disease have led to substantial confusion among both physicians and patients. This study was designed to bring more clarity to the diagnosis and potential treatment of HAE with normal C1INH. An international symposium of experts was convened to review the field and develop consensus opinions that could help clinicians who evaluate and manage these patients. Criteria were developed for the diagnosis of HAE with normal C1INH in patients with recurrent angioedema in the absence of concurrent urticaria. In addition, potential therapeutic strategies are discussed. The consensus criteria developed during this symposium will allow physicians to better diagnose and treat patients with HAE with normal C1INH.

Antenatal risk factors for peanut allergy in children.

BACKGROUND: Prenatal factors may contribute to the development of peanut allergy. We evaluated the risk of childhood peanut allergy in association with pregnancy exposure to Rh immune globulin, folic acid and ingestion of peanut-containing foods. METHODS: We conducted a web-based case-control survey using the Anaphylaxis Canada Registry, a pre-existing database of persons with a history of anaphylaxis. A total of 1300 case children with reported peanut allergy were compared to 113 control children with shellfish allergy. All were evaluated for maternal exposure in pregnancy to Rh immune globulin and folic acid tablet supplements, as well as maternal avoidance of dietary peanut intake in pregnancy. RESULTS: Receipt of Rh immune globulin in pregnancy was not associated with a higher risk of peanut allergy (odds ratio [OR] 0.86, 95% confidence interval [CI] 0.51 to 1.45), nor was initiation of folic acid tablet supplements before or after conception (OR 0.53, 95% CI 0.19 to 1.48). Complete avoidance of peanut-containing products in pregnancy was associated with a non-significantly lower risk of peanut allergy (OR 0.53, 95% CI 0.27 to 1.03). CONCLUSION: The risk of childhood peanut allergy was not modified by the following common maternal exposures in pregnancy: Rh immune globulin, folic acid or peanut-containing foods. CLINICAL IMPLICATIONS: Rh immune globulin, folic acid supplement use and peanut avoidance in pregnancy have yet to be proven to modulate the risk of childhood anaphylaxis to peanuts. CAPSULE SUMMARY: Identification of prenatal factors that contribute to peanut allergy might allow for prevention of this life-threatening condition. This article explores the role of three such factors.

Factor XII mutations, estrogen-dependent inherited angioedema, and related conditions.

The clinical, biochemical and genetic features of the conditions known as estrogen-dependent inherited angioedema, estrogen-associated angioedema, hereditary angioedema with normal C-1 inhibitor, type III angioedema, or factor XII angioedema are reviewed. Discussion emphasizes pathogenesis, diagnosis, and management.

Hereditary and acquired angioedema: problems and progress: proceedings of the third C1 esterase inhibitor deficiency workshop and beyond.

Hereditary angioedema (HAE), a rare but life-threatening condition, manifests as acute attacks of facial, laryngeal, genital, or peripheral swelling or abdominal pain secondary to intra-abdominal edema. Resulting from mutations affecting C1 esterase inhibitor (C1-INH), inhibitor of the first complement system component, attacks are not histamine-mediated and do not respond to antihistamines or corticosteroids. Low awareness and resemblance to other disorders often delay diagnosis; despite availability of C1-INH replacement in some countries, no approved, safe acute attack therapy exists in the United States. The biennial C1 Esterase Inhibitor Deficiency Workshops resulted from a European initiative for better knowledge and treatment of HAE and related diseases. This supplement contains work presented at the third workshop and expanded content toward a definitive picture of angioedema in the absence of allergy. Most notably, it includes cumulative genetic investigations; multinational laboratory diagnosis recommendations; current pathogenesis hypotheses; suggested prophylaxis and acute attack treatment, including home treatment; future treatment options; and analysis of patient subpopulations, including pediatric patients and patients whose angioedema worsened during pregnancy or hormone administration. Causes and management of acquired angioedema and a new type of angioedema with normal C1-INH are also discussed. Collaborative patient and physician efforts, crucial in rare diseases, are emphasized. This supplement seeks to raise awareness and aid diagnosis of HAE, optimize treatment for all patients, and provide a platform for further research in this rare, partially understood disorder.

Objective psychological measurement and clinical assessment of anxiety in adverse drug reactions.

BACKGROUND: A confounding factor in the diagnosis of adverse drug reactions (ADRs) is the psychological state of the patient. Patients with underlying anxiety and related disorders may present with psychogenic reactions, which involve physiologic responses originating from psychological, rather than organic factors. OBJECTIVE: To examine the contribution of anxiety and related disorders to adverse drug events. METHODS: Participants from an adverse drug reaction clinic completed the Trauma Symptom Checklist-40 (TSC-40), a 40-item questionnaire consisting of six subscales: anxiety, depression, dissociation, sexual abuse trauma index (SATI), sexual problems, and sleep disturbance. Physicians assessed the likelihood that adverse events were due to anxiety or drug(s) by providing an anxiety score (0 to 10) and an ADR score (0 to 10), respectively, for each participant. RESULTS: Patients clinically assessed as having "high anxiety" (anxiety score 7-10 and ADR score 0-3; n = 11) scored higher than patients clinically assessed as having a "true ADR" (anxiety score 0-3 and ADR score 7-10; n = 19) on the TSC-40 total (P = 0.006) as well as anxiety (P = 0.012), depression (P = 0.007), and SATI subscales (P = 0.016). CONCLUSION: This study is the first to use a validated psychological measurement to indicate that a substantial percentage of reported adverse drug events may in fact be a manifestation of underlying anxiety and/or related disorders. We suggest that mechanisms of symptom generation may be analogous to those operative in idiopathic environmental intolerance.

Estrogen-dependent inherited angioedema.

Classic forms of hereditary angioedema are characterized clinically by recurrent episodes of angioedema, biochemically by reduced C1 inhibitor level and/or function, and genetically by a heterogeneous group of mutations in the C1 inhibitor gene that have an autosomal dominant mode of transmission. Androgens and estrogens have significant clinical effects in patients with hereditary angioedema, and tend to have antagonist effects of the levels of C1 inhibitor protein. Androgens increase the levels of C1 inhibitor protein, reduce attacks of angioedema, and thus are an important therapy for patients. The mechanisms by which the sex steroid hormones achieve these effects are not understood. The recent recognition of a novel estrogen-dependent form of angioedema may offer important insights into the mechanisms by which the sex hormones exert their effects, and the pathogenesis and treatment of both estrogen-dependent and classic forms of hereditary angioedema.

Idiopathic environmental intolerance: Part 1: A causation analysis applying Bradford Hill's criteria to the toxicogenic theory.

Idiopathic environmental intolerance (IEI) is a descriptor for a phenomenon that has many names including environmental illness, multiple chemical sensitivity and chemical intolerance. Toxicogenic and psychogenic theories have been proposed to explain IEI. This paper presents a causality analysis of the toxicogenic theory using Bradford Hill's nine criteria (strength, consistency, specificity, temporality, biological gradient, biological plausibility, coherence, experimental intervention and analogy) and an additional criteria (reversibility) and reviews critically the scientific literature on the topic. The results of this analysis indicate that the toxicogenic theory fails all of these criteria. There is no convincing evidence to support the fundamental postulate that IEI has a toxic aetiology; the hypothesised biological processes and mechanisms are implausible.

Idiopathic environmental intolerance: Part 2: A causation analysis applying Bradford Hill's criteria to the psychogenic theory.

Toxicogenic and psychogenic theories have been proposed to explain idiopathic environmental intolerance (IEI). Part 2 of this article is an evidence-based causality analysis of the psychogenic theory using an extended version of Bradford Hill's criteria. The psychogenic theory meets all of the criteria directly or indirectly and is characterised by a progressive research programme including double-blind, placebo-controlled provocation challenge studies. We conclude that IEI is a belief characterised by an overvalued idea of toxic attribution of symptoms and disability, fulfilling criteria for a somatoform disorder and a functional somatic syndrome. A neurobiological diathesis similar to anxiety, specifically panic disorder, is a neurobiologically plausible mechanism to explain triggered reactions to ambient doses of environmental agents, real or perceived. In addition, there is a cognitively mediated fear response mechanism characterised by vigilance for perceived exposures and bodily sensations that are subsequently amplified in the process of learned sensitivity. Implications for the assessment and treatment of patients are presented.