Prevalence of sensitivity to sulfiting agents in asthmatic patients

Hypersensitivity Reactions to Food Additives-Preservatives, Antioxidants, Flavor Enhancers

There have been reports of food hypersensitivity reactions to food additives (HFA) for many years. The mechanisms of HFA and their frequency are difficult to precisely define, as most of the data come from outdated studies with poor methodology. In 2020, the European Food Safety Authority completed a review of additives, examining their influence on the occurrence of HFA, but did not include all of them. The aim of this review is to systematise knowledge about selected groups of food additives (FAs) and the HFA induced by them. We also briefly discuss the issues of diagnosis and therapy in this disease. FAs are commonly used in prosscessed foods, but HFA appears to be a rare phenomenon. Identification of the FA responsible for hypersensitivity and its treatment is difficult. Diagnosis is a challenge for the clinician and for the patient. A food diary is a helpful diagnostic tool. It allows diet therapy to be monitored based on the partial or complete elimination of products containing a harmful additive. An elimination diet must not be deficient, and symptomatic pharmacotherapy may be necessary if its application is ineffective. Taking all this into account, we conclude that it is necessary to conduct randomised multicentre studies based on the double-blind placebo control protocol in this field.

Adverse Reactions to Illicit Drugs (Marijuana, Opioids, Cocaine) and Alcohol

Drug allergy has been a research topic within the allergy field for decades. However, many drug reactions presumed to be of allergic nature are not and originate from different mechanisms. Drug-induced reactions can affect numerous organ systems, present with various symptoms, and have more than 1 mechanism of action. In this rostrum article, we want to give an overview of the different allergic and nonallergic reactions that can be expected with the (illicit) use of cannabis, cocaine, opioids, and alcohol. In addition, this article focuses on the different methods available to diagnose allergy related to these 4 drug types and highlight the pitfalls of nonallergic reactions or allergy "mimickers" complicating the diagnosis of true drug allergy. Finally, the impact on current medical practices and future research in support of the allergist in diagnosis and treatment of these medical problems is addressed.

Allergy to food additives

PURPOSE OF REVIEW

To provide an update of the studies concerning the diagnosis and management of food additives allergy.

RECENT FINDINGS

Additives improve specific characteristics of food products, but they may induce allergic even life-threatening reactions. Physical examination and medical history are basic to assess specific in-vivo and in-vitro tests. The only treatment for allergic patients consists in avoiding the food containing culprit additives. High-risk patients should be able to recognize severe reactions and self-manage them.

SUMMARY

The prevalence of adverse reactions to food additives is low, and it may depend on comorbidities, like asthma or chronic idiopathic urticaria. Food labels may help the correct identification of ingredients. Natural additives like spices should cause immediate reactions because of a pollen-sensitization or panallargen proteins presence. Additive-free diets may help the patient care, but the authors suggest assessing an oral food challenge with the culprit substance if there are no contraindications.

Hypersensitivity reactions to food and drug additives: problem or myth?

BACKGROUND AND AIM OF THE WORK

The possibility of an allergic reaction or an intolerance to additives is frequently suspected by parents, especially for chronic illness with frequent exacerbations such as atopic dermatitis or chronic urticaria. For more than 50 years, potential adverse reactions to additives have been suggested, but to date data are conflicting. The purpose of this article is to provide the clinicians with general information about additives and adverse reactions to them and to suggest a practical approach to children suspected to have reactions to food additives.

METHODS

We performed an extensive research on all English-language Medline articles, case reports and reviews published online until December 2018. Used search terms were: food additives, food dye, adverse reactions, food allergy, food hypersensitivity, intolerance, drugs, children.

RESULTS

There are only few case reports of adverse reactions in childhood with a clear involvement of additives. In this review article we reported the associations between additives and adverse reactions described in literature, in order to inform the pediatrician about the potential clinical manifestations.

CONCLUSIONS

Prior to suspect an adverse reaction to additives, it is important to rule out other possible causes: the diagnostic process is complicated and rarely conclusive. The gold standard is the double-blind placebo controlled oral challenge after an exclusion diet.

Dental treatment in children with asthma - a review

This article aims to explain the effects of long-term use of asthma medications. It will discuss the effects of asthma on the oral cavity, as well considerations for the dentist when treating asthmatic patients. It will also explain how to manage asthma in the dental setting and provide advice on maintaining oral health for asthmatic patients.

Gastric mucosal irritation following oral exposure to sodium metabisulphite: A reproducible effect?

Sulphiting agents, such as sodium metabisulphite (SM), are used in food as bleaching agents and to prevent browning reactions. A 1972 repeat dose study in rats found that dietary sulphites caused irritation of the stomach with inflammation, hyperplasia and bleeding. We conducted a 7-day dietary study in rats to confirm that stomach lesions were the most sensitive toxicological endpoint. Rat feed was prepared daily with 0%, 0.25%, 0.5%, 1% or 4% (w/w) SM. Parameters included clinical signs, feed and water intake, bodyweight gain, haematology, serum protein chemistry, necropsy findings and gastrointestinal histopathology. There were no treatment-related clinical signs or gastrointestinal lesions. Mean bodyweight gain was markedly decreased in the 4% (w/w) SM group although feed consumption was marginally depressed. Slightly lower mean values for RBC, Hb, Hct, total WBC and lymphocyte count were observed in the 4% SM group with no evidence of compensatory haematopoiesis. The gastric lesions in rats observed in a 1972 study of dietary SM for 10-56 days could not be replicated. These findings create uncertainty around the most relevant toxicological endpoint to establish a suitable health based guidance value, which can only be overcome if a robust long-term dietary study is undertaken.

Sensitivity to food additives, vaso-active amines and salicylates: a review of the evidence

Although there is considerable literature pertaining to IgE and non IgE-mediated food allergy, there is a paucity of information on non-immune mediated reactions to foods, other than metabolic disorders such as lactose intolerance. Food additives and naturally occurring 'food chemicals' have long been reported as having the potential to provoke symptoms in those who are more sensitive to their effects. Diets low in 'food chemicals' gained prominence in the 1970s and 1980s, and their popularity remains, although the evidence of their efficacy is very limited. This review focuses on the available evidence for the role and likely adverse effects of both added and natural 'food chemicals' including benzoate, sulphite, monosodium glutamate, vaso-active or biogenic amines and salicylate. Studies assessing the efficacy of the restriction of these substances in the diet have mainly been undertaken in adults, but the paper will also touch on the use of such diets in children. The difficulty of reviewing the available evidence is that few of the studies have been controlled and, for many, considerable time has elapsed since their publication. Meanwhile dietary patterns and habits have changed hugely in the interim, so the conclusions may not be relevant for our current dietary norms. The conclusion of the review is that there may be some benefit in the removal of an additive or a group of foods high in natural food chemicals from the diet for a limited period for certain individuals, providing the diagnostic pathway is followed and the foods are reintroduced back into the diet to assess for the efficacy of removal. However diets involving the removal of multiple additives and food chemicals have the very great potential to lead to nutritional deficiency especially in the paediatric population. Any dietary intervention, whether for the purposes of diagnosis or management of food allergy or food intolerance, should be adapted to the individual's dietary habits and a suitably trained dietitian should ensure nutritional needs are met. Ultimately a healthy diet should be the aim for all patients presenting in the allergy clinic.

Food allergy: a practice parameter update-2014

This parameter was 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 & Immunology (JCAAI). The AAAAI and the ACAAI have jointly accepted responsibility for establishing "Food Allergy: A practice parameter update-2014." This is a complete and comprehensive document at the current time. The medical environment is a changing one, 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, ACAAI, and JCAAI. These parameters are not designed for use by pharmaceutical companies in drug promotion.

Selective and sensitive chromofluorogenic detection of the sulfite anion in water using hydrophobic hybrid organic-inorganic silica nanoparticles

In water and wine: Chromofluorogenic detection of the sulfite anion in pure water was accomplished by using a new hybrid organic-inorganic material that contained a probe entrapped in hydrophobic biomimetic cavities. This material was used for the detection of sulfite in red wine.

Alteration of drug metabolizing enzymes in sulphite oxidase deficiency

The aim of this study was to investigate the possible effects of sulphite oxidase (SOX, E.C. 1.8.3.1) deficiency on xenobiotic metabolism. For this purpose, SOX deficiency was produced in rats by the administration of a low molybdenum diet with concurrent addition of 200 ppm tungsten to their drinking water. First, hepatic SOX activity in deficient groups was measured to confirm SOX deficiency. Then, aminopyrine N-demethylase, aniline 4-hydroxylase, aromatase, caffeine N-demethylase, cytochrome b5 reductase, erythromycin N-demethylase, ethoxyresorufin O-deethylase, glutathione S-transferase, N-nitrosodimethylamine N-demethylase and penthoxyresorufin O-deethylase activities were determined to follow changes in the activity of drug metabolizing enzymes in SOX-deficient rats. Our results clearly demonstrated that SOX deficiency significantly elevated A4H, caffeine N-demethylase, erythromycin N-demethylase and N-nitrosodimethylamine N-demethylase activities while decreasing ethoxyresorufin O-deethylase and aromatase activities. These alterations in drug metabolizing enzymes can contribute to the varying susceptibility and response of sulphite-sensitive individuals to different drugs and/or therapeutics used for treatments.

Intolerance to food additives - does it exist?

'Food intolerance' is often confused with a range of adverse symptoms which may be coincidental to ingestion of food. 'Food intolerance' is defined as a reaction in which symptoms must be objectively reproducible and not known to involve an immunological mechanism. A more precise term is non-allergic food hypersensitivity, which contrasts with food allergies which are due to an immunological mechanism. Some children will experience food reactions to food additives. Reported symptoms range from urticaria/angioedema to hyperactive behaviours. While parents/carers report that over one fifth of children experience of food reaction, only 1 in 20 of these are confirmed to have a non-allergic food hypersensitivity on testing.

Endogenously generated sulfur dioxide and its vasorelaxant effect in rats

AIM

The present study was designed to explore the endogenous production and localization of the sulfur dioxide (SO2)/aspartate aminotransferase pathway in vascular tissues of rats and to examine its vasorelaxant effect on isolated aortic rings,as well as the possible mechanisms.

METHODS

The content of SO2 in the samples was determined by using high performance liquid chromatography with fluorescence detection. Aspartate aminotransferase activity and its gene expression were measured by an enzymatic method and quantitative RT-PCR, respectively. Aspartate aminotransferase mRNA location in aorta was detected by in situ hybridization. The vasorelaxant effect of SO2 on isolated aortic rings of the rats was investigated in vitro. L-type calcium channel blocker, nicardipine, and L-type calcium channel agonist, Bay K8644, were used to explore the mechanisms by which SO2 relaxed the aortic rings.

RESULTS

Aorta had the highest SO2 content among the vascular tissues tested (P<0.01). The aortic aspartate aminotransferase mRNA located in endothelia and vascular smooth muscle cells beneath the endothelial layer.Furthermore, a physiological dose of the SO2 derivatives (Na2SO3/NaHSO3) relaxed isolated artery rings slightly, whereas higher doses (1-12 mmol/L) relaxed rings in a concentration-dependent manner. Pretreatment with nicardipine eliminated the vasorelaxant response of the norepinephrine-contracted rings to SO2 completely. Incubation with nicardipine or SO2 derivatives successfully prevented vasoconstriction induced by Bay K8644.

CONCLUSION

Endogenous SO2 and its derivatives have a vasorelaxant function, the mechanisms of which might involve the inhibition of the L-type calcium channel.

Food Intolerance and childhood asthma: what is the link?

Food allergies and asthma are increasing worldwide. It is estimated that approximately 8% of children aged <3 years have food allergies. Foods can induce a variety of IgE-mediated, cutaneous, gastrointestinal, and respiratory reactions. The most common foods responsible for allergic reactions in children are egg, milk, peanut, soy, fish, shellfish, and tree nuts. Asthma alone as a manifestation of a food allergy is rare and atypical. Less than 5% of patients experience wheezing without cutaneous or gastrointestinal symptoms during a food challenge. In addition to acute respiratory symptoms, a food allergy may also induce airway hyper-responsiveness beyond the initial reaction. This process can occur in patients who do not demonstrate a decrease in lung function during the reaction. Inhalation of aerosolized food particles can cause respiratory symptoms in selected food-allergic individuals, particularly with fish and shellfish during cooking and aerosolization. However, this has not been demonstrated with the smelling of, or casual contact with, peanut butter. Rarely, food additives such as sulfating agents can cause respiratory reactions. This reaction occurs primarily in patients with underlying asthma, particularly in patients with more severe asthma. In contrast, there is no convincing evidence that tartrazine or monosodium glutamate can induce asthma responses. Although food-induced asthma is rare, it is common for patients and clinicians to perceive that food can trigger asthma. Avoidance of specific foods or additives has not been shown to improve asthma, even in patients who may perceive that a particular food worsens their asthma.However, patients with underlying asthma are more likely to experience a fatal or near-fatal food reaction. Food reactions tend to be more severe or life threatening when they involve the respiratory tract. The presence of a food allergy is a risk factor for the future development of asthma, particularly for children with sensitization to egg protein. The diagnosis of a food allergy includes skin or in vitro testing as an initial study when the history suggests food allergy. While negative testing generally rules out a food allergy, positive testing should be followed by a food-challenge procedure for a definitive diagnosis. The CAP-RAST FEIA (CAP-radioallergosorbent test [RAST] fluoroenzyme immunoasssay system [FEIA]) is an improved in vitro measure that in some cases may decrease the need for food challenges. However, similar to skin testing and the RAST, there is good sensitivity but poor specificity, such that specific challenges are often warranted.

Common medications prescribed for adolescent dental patients

Common prescription medications taken by adolescent patients include various psychopharmacologic agents (to manage depression,obsessive-compulsive disorders, and attention deficit/hyperactivity disorders), pulmonary drugs (to prevent and treat asthma), and dermatologic agents (to treat acne). Other agents encountered when treating adolescent patients are antidiabetes agents, antibiotics, and birth control medications. This overview identifies prescription medications commonly used by adolescent patients and discusses their possible impact on dental care.

Adverse reactions to food additives

OBJECTIVES

To summarize the literature related to the classification of food additives and their reported adverse reactions and to provide a practical approach for evaluation of patients suspected of having such reactions.

DATA SOURCES

Information was derived from selected reviews and original articles published in peer-reviewed journals and from authoritative textbook chapters, supplemented by the clinical experience of the authors.

STUDY SELECTION

Priority was given to studies that used blinded, placebo-controlled oral challenges to confirm adverse reactions to food additives. In addition, selected, appropriately evaluated case reports are included.

RESULTS

A large number of food additives are widely used in the food industry. Adverse reactions to additives seem to be rare but are likely underdiagnosed in part due to a low index of suspicion. Numerous symptoms have been attributed to food additive exposure, but the cause-and-effect relationship has not been well demonstrated in all.

CONCLUSIONS

Reactions to food additives should be suspected in patients who report symptoms to multiple unrelated foods or to a certain food when commercially prepared but not when homemade and the allergy evaluation rules out a role for food protein. It is also prudent to investigate food additives in patients considered to have idiopathic reactions. There is a minor role for skin testing or in vitro testing. Oral challenge testing with common additives, preferably preceded by a trial of an additive-free diet, is the definitive procedure for detecting the offending agent. Once the specific additive is identified, management is basically avoidance of all its forms.

Food allergy and additives: triggers in asthma

Exposure to food allergens can cause a varied pattern of respiratory symptoms, with allergic responses ranging from asthma symptoms to occupational asthma. Food allergy in a patient presenting as asthma tends to indicate a more severe disease constellation. Patients with underlying asthma experience more severe and life-threatening allergic food reactions. When a food reaction involves respiratory symptoms, it is almost always a more severe reaction compared with reactions that do not involve the respiratory tract. Susceptible patients may even react to a causative food on inhalation without ingestion. However, isolated asthma or rhinitis symptoms without concomitant cutaneous or gastrointestinal symptoms are rare events.

Sulfite-mediated oxidative stress in kidney cells

BACKGROUND

Chronic renal failure has been associated with oxidative stress. Serum sulfite, sulfate, cysteine, homocysteine, cysteine sulfinic acid, and gamma-glutamylcysteine are elevated in patients on hemodialysis, suggesting an accelerated catabolism of sulfur-containing amino acids or a reduced elimination of sulfite/sulfate, or both. Administration of metabisulfite has also been shown to damage kidney cells.

METHODS

Measurement of reactive oxygen species (ROS) was performed with the fluorescence of dichlorofluorescein (DCF), and that of intracellular ATP was by the luciferin-luciferase reaction. Oxidation of sulfite and succinate by isolated mitochondria from rat kidney was monitored polarographically. The fluorescent probe, 5, 5', 6, 6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolcarbocyanine iodide (JC-1) was employed to assess any loss in membrane potential in energized respiring mitochondria. Activities of glutamate and malate dehydrogenases (GDH, MDH, respectively) were assayed by the spectrophotometric measurement of NADH. Sulfite was determined by HPLC-fluorimetric measurement of monochlorobimane-sulfite and cell viability was by the MTT procedure.

RESULTS

An immediate increase in ROS followed exposure of Madin-Darby canine kidney (MDCK), type II, and opossum kidney (OK) cells to 5-500 micromol/L sulfite. Depletion of intracellular ATP was also observed. A low rate of oxidation of 100 micromol/L sulfite was observed polarographically in isolated kidney mitochondria, but ADP-stimulated State 3 respiration was not apparent. ATP biosynthesis from the oxidation of glutamate in rat kidney mitochondria was significantly inhibited by coincubation with 100 micromol/L sulfite; this was not the case with malate, succinate, and TMPD/ascorbate. However, activities of both GDH and MDH in kidney mitochondrial extract were inhibited. The mitochondrial membrane potential and cell viability were not compromised.

CONCLUSION

Micromolar sulfite elicited an immediate increase in ROS in MDCK, type II, and OK cells. This was accompanied by a depletion of intracellular ATP, which could be explained by its inhibitory effect on mitochondrial GDH. Although MDH was similarly inhibited, the impact was buffered by the high level of this enzyme in kidney mitochondria.

A mechanism of sulfite neurotoxicity: direct inhibition of glutamate dehydrogenase

Exposure of Neuro-2a and PC12 cells to micromolar concentrations of sulfite caused an increase in reactive oxygen species and a decrease in ATP. Likewise, the biosynthesis of ATP in intact rat brain mitochondria from the oxidation of glutamate was inhibited by micromolar sulfite. Glutamate-driven respiration increased the mitochondrial membrane potential (MMP), and this was abolished by sulfite but the MMP generated by oxidation of malate and succinate was not affected. The increased rate of production of NADH from exogenous NAD+ and glutamate added to rat brain mitochondrial extracts was inhibited by sulfite, and mitochondria preincubated with sulfite failed to reduce NAD+. Glutamate dehydrogenase (GDH) in rat brain mitochondrial extract was inhibited dose-dependently by sulfite as was the activity of a purified enzyme. An increase in the Km (glutamate) and a decrease in Vmax resulting in an attenuation in Vmax/Km (glutamate) at 100 microm sulfite suggest a mixed type of inhibition. However, uncompetitive inhibition was noted with decreases in both Km (NAD+) and Vmax, whereas Vmax/Km (NAD+) remained relatively constant. We propose that GDH is one target of action of sulfite, leading to a decrease in alpha-ketoglutarate and a diminished flux through the tricarboxylic acid cycle accompanied by a decrease in NADH through the mitochondrial electron transport chain, a decreased MMP, and a decrease in ATP synthesis. Because glutamate is a major metabolite in the brain, inhibition of GDH by sulfite could contribute to the severe phenotype of sulfite oxidase deficiency in human infants.

Activation of human polymorphonuclear neutrophils by environmental contaminants

The toxicity of chemicals of environmental concern to the immune system has been primarily evaluated in animals and, to a lesser extent, in humans. In particular, the effects of various pollutants on B-cell, T-cell, natural killer cells, and monocyte-macrophage cells have been the focus of several reports, but polymorphonuclear neutrophils have largely been neglected. Recent data indicate that neutrophils are important targets for such chemicals, suggesting a potential role of these products in the development of the inflammatory process. The bulk of this review will focus on the role of certain environmental pollutants on human neutrophil cell physiology.

Adverse reactions to food additives

There are thousands of additives used by the food industry for a variety of purposes in the foods we eat. However, only a small number have been implicated in causing adverse reactions in humans. Although there are reported cases of individuals who have reactions to single additives, most of the medical literature involves patients with asthma or chronic idiopathic urticaria/angioedema whose conditions are exacerbated after ingestion of food additives. Many of these reports are characterized by poorly controlled challenge procedures. Recent studies performed under properly controlled conditions imply that sensitivity to food additives in patients with chronic urticaria/angioedema is very uncommon.

Adverse drug reactions to local anesthesia

A dentist's ability to safely administer regional anesthesia is essential for dental practice. Local anesthetic solutions used in the United States for dental anesthesia are formulated with several components. The contents of a standard local anesthetic cartridge may include an amide or ester local anesthetic drug, an adrenergic vasoconstrictor, and an antioxidant. In susceptible patients, any of these components may induce systemic, dose-dependent adverse reactions. Although extremely rare, allergic reactions may also occur. Signs and symptoms of the various adverse reactions associated with local anesthetics are quite distinctive, permitting rapid diagnosis and treatment. Serious reactions are extremely infrequent and, when treated properly, unlikely to result in significant morbidity or mortality.

Wine-induced asthma: a placebo-controlled assessment of its pathogenesis

BACKGROUND

The sulfite family of food additives has been implicated in the pathogenesis of wine-induced asthma. However, the evidence supporting this is weak, and because wines have many hundreds of components, nonsulfite-associated mechanisms may also play a role.

OBJECTIVES

The aim of the study was to assess the potential sensitivity of persons with asthma to nonsulfite components in wine by using low-sulfite wine challenges.

METHODS

Sixteen adults with a strong history of wine-induced asthma were challenged with both low-sulfite red and white wines and wine-placebo drinks. Challenges were performed double blind, using a Latin square design, with lung function being assessed before the challenge and at 5, 10, 15, 30, and 60 minutes after the challenge. Subsequently, single-blind challenges with high-sulfite white wine were also completed in 10 individuals whose lack of reactivity to low-sulfite white wine suggested possible reactivity to sulfite additives.

RESULTS

The mean FEV1; forced expiratory flow, mid-expiratory phase; and peak expiratory flow of subjects to low-sulfite red and white wines and red and white placebo wines were not significantly different. Furthermore, with a predetermined criterion of a fall in FEV1 of more than 15% representing a positive challenge, only one individual exhibited a positive reaction in the presence of a negative response to placebo. Only 2 of the 10 test individuals who were challenged with a high-sulfite wine demonstrated a marked and rapid fall in FEV1. Reactivity to low-sulfite wines appears to occur only in a small number of individuals who report sensitivity to wines, suggesting that the sulfite additives may be the major cause of wine-induced asthmatic reactions. However, direct challenge with high-sulfite wine revealed only 2 clear reactions in this asthma cohort.

CONCLUSION

Wine-induced asthma appears to be a complex phenomenon and may involve several mechanisms that are codependent.

Pickled onion-induced asthma: a model of sulfite-sensitive asthma?

BACKGROUND

Asthma elicited by sulfite ingestion has been mainly described in steroid-dependent and in non-atopic asthmatics. We have studied a group of 18 young extrinsic asthmatics who presented with asthma attacks immediately after eating pickled onions.

OBJECTIVE

The aim of this study is to ascertain if these asthma attacks are elicited by sulfites contained in pickled onions and the influence of the dose and pH of onions.

METHODS

The bronchial hyperreactivity of the patients was assessed by a methacholine challenge test. Oral challenge tests were performed with sodium metabisulfite (MSB) diluted in lemon juice at pH 4.2 and at pH 3.3 (only in patients who did not react with pH 4.2). Two types of pickled onions, Spanish and Dutch pickled onions, were used for oral challenge in seven of the patients. The Monier-Williams method was used to measure the SO2 concentration in pickled onions.

RESULTS

The oral provocation test with MBS, pH 4.2, elicited a positive response in six patients (33.3%) and the test at pH 3.3 was positive in three out of 12. No significant difference in PD20 values was found between these groups. Three of the seven patients challenged with Spanish pickled onions had a positive reaction but had no reaction with Dutch pickled onions. The SO2 concentration in Spanish pickled onions varied between 765 and 1182 ppm while in Dutch pickled onions were 200 ppm; this exceeded the permitted level (100 ppm). SO2 release in Spanish pickled onion samples was nearly 2.5 times higher when the pH of the sample decreased from 4.2 to 3.3.

CONCLUSION

High levels of SO2 in Spanish pickled onions, and their low pH (3.3) would be the responsible factors of the asthmatic outbreaks after ingestion of Spanish pickled onions by these patients.

Prevalence of food additive intolerance

1. The existing prevalence estimates of food additive intolerance are being reviewed. 2. In the EEC report the estimated frequency of food additive intolerance is 0.03% to 0.15% based on data from patient groups. 3. The British population study results in a prevalence estimate of 0.026%. The challenged population is 81 children and adults with a history of reproducible clinical symptoms after ingestion of food additives. 4. In the Danish population study a prevalence of 1-2% is found in children age 5-16. In this study a total of 606 children mainly with atopic disease have been challenged. 5. The prevalence estimates vary with a factor 100. As the results vary so do the study populations. 6. If the different study populations are accounted for, a common conclusion can be drawn: Food additive intolerance is found in adults with atopic symptoms from the respiratory tract and skin. The prevalence estimates are questionable but may be less than 0.15%. In adults and children with reproducible, and with more subjective symptoms, such as headache and behavioural/mood change the prevalence is even lower (0.026%). Food additive intolerance is primarily found in atopic children with cutaneous symptoms where the additive is aggravating an existing disease. The prevalence of food additive intolerance in children age 5-16 is 1-2%.

The role of nutrition in sickness and in health

This article reviews the importance of food and water for survival and the wide ranges of nutrient intake capable of sustaining reproduction and growth. It also reviews the different types of adverse reactions to foods including hypersensitivity or allergic reactions, pharmacologic and metabolic adverse responses to foods, and natural and industrial toxins in the food chains. The article concludes with recommendations for dealing with patients who advocate the use of "natural" foods and products.

Foods perceived by adults as causing adverse reactions

This study was undertaken to identify differences in offending foods reported by 45 patients with classic symptoms of food allergy and/or subjective food-related complaints not traditionally associated with food allergy. On the basis of a comprehensive clinical history, skin testing, and double-blind food challenges, patients were diagnosed as having confirmed (n = 22) or unconfirmed (n = 23) adverse reactions to foods. The majority of patients in both groups were women-17 of those with confirmed reactions and 21 of those with unconfirmed reactions. Individuals with confirmed reactions were significantly younger, 34.8 +/- 10.9 years, than those with unconfirmed reactions, 41.5 +/- 9.6 years. The symptoms and reaction patterns of adults with confirmed reactions were generally consistent with immunoglobulin E-mediated food hypersensitivity. Individuals with unconfirmed reactions were more likely to report frequently occurring, delayed-onset symptoms of a nonspecific nature, and they had an average of five times as many foods causing adult-onset symptoms than those with confirmed reactions. Adults with confirmed reactions more often reported common food allergens such as tree nuts, legumes, and crustaceans; those with unconfirmed reactions were more apt to name foods not commonly implicated in adult food allergies confirmed by conventional diagnostic methods. The types of offending foods reported suggested that individuals with unconfirmed reactions were influenced by the popular news media and clinical ecology-oriented literature. Their use of nutrition supplements was consistent with the attitude of health activism. Such individuals may seek nontraditional health care or adopt questionable dietary practices. Individuals with adverse food reactions of a nonspecific nature pose challenging problems to dietitians.

Contraindications to vasoconstrictors in dentistry: Part II. Hyperthyroidism, diabetes, sulfite sensitivity, cortico-dependent asthma, and pheochromocytoma

Dentists are aware of contraindications to the use of vasoconstrictors in patients with cardiovascular diseases. However, there are some other noncardiac conditions we should know. This article discusses the absolute contraindications to the use of vasoconstrictors in patients with a history of hyperthyroidism, diabetes, allergy to sulfites, asthma, and pheochromocytoma.

Review of parenteral sulfite reactions

Sulfiting agents are commonly used in parenteral emergency drugs, including epinephrine, dexamethasone, dobutamine, dopamine, norepinephrine, phenylephrine, procainamide, and physostigmine. Published anaphylactic or asthmatic reactions have been associated with sulfited local anesthetics, gentamicin, metoclopramide, doxycycline, and vitamin B complex. The reactions differ from those caused by foods, in that they have a rapid onset, have no predilection for steroid-dependent asthmatics, and do not always coincide with a positive oral challenge. The mechanism is unknown, but may involve a dose-related reaction with disulfide bonds on sympathetic and parasympathetic receptor membranes. Patients with a history of positive oral challenge to 5-10 mg of sulfite may be at increased risk of developing a reaction to parenteral sulfites. Despite documentation of sensitivity, sulfites should not be withheld from patients experiencing a life-threatening emergency. Non-sulfited alternatives are often available, and should be used preferentially.

Diagnosis of sulfite and aspirin sensitivity

In addition to the well-recognized allergic responses of individuals to high mol wt substances, such as pollens, molds, and animal dander, susceptible asthmatics may also experience adverse reactions to low mol wt substances such as sulfites, ASA, and NSAIDs. The diagnosis of sulfite and aspirin sensitivity can only be made by appropriately conducted provocative challenge. Every precaution should be taken to assure the safety of the patients, since life-threatening reactions can occur. A better understanding of the mechanism or mechanisms involved in the adverse reactions to these substances will not only provide information to better diagnose the reaction, but also improve our understanding of the treatment of asthma.