Bisulfite sensitivity manifesting as allergy to local dental anesthesia

True Allergies to Articaine: A 25-Year Analysis

Background: Although allergic reactions to amide local anesthetics (LA) are rare, it is important for medical professionals to be aware of their potential occurrence. Despite the fact that articaine is one of the most commonly used LA in dentistry, a survey of documented cases of allergies to articaine is absent from the literature. The objective of this review was to ascertain how often true allergies to articaine, verified by standard allergological procedures, have been reported over the last 25 years. Methods: A comprehensive review of the literature from 1 January 2000 to 31 December 2024 was conducted using the PubMed-MEDLINE database. The search was limited to articles investigating suspected allergy to articaine. The search strategy encompassed indexing terms, keywords, and free-text words, complemented by an extensive manual search. The final determination was based on the application of skin and/or challenge tests as the gold standard for identifying articaine as the causative agent. Results: During the investigation period, 10 case reports and six case series, encompassing 29 patients with a confirmed true allergy to articaine, were identified. The age of the patients ranged from 8 to 65 years, with a median age of 34 years. Of these patients, 20 were diagnosed with an immediate type I allergy, while 5 patients exhibited a delayed type IV allergy. In four cases the specific type of allergy was not mentioned. In the majority of cases an intradermal test (IDT) was employed to ascertain the specific type of allergy. Cross-reactivity with other amide LA was reported in three cases. Conclusions: True allergies to articaine are exceedingly rare. Investigation strategies should include a combination of a thorough clinical history and a standardized allergological procedure entailing skin tests and challenge. Only a comprehensive approach ensures the accurate identification of affected patients and facilitates the selection of a tolerated LA.

Neurological Complications of Local Anesthesia in Dentistry: A Review

Local anesthesia is a technique that temporarily desensitizes a specific body area, typically for a surgical procedure, dental work, or pain management. It is described as a sensation loss in a specific area of the body due to depression of excitation in the nerve endings or due to the inhibition of the conduction process within the peripheral nerves. It allows for safer and more comfortable medical procedures, reducing the need for general anesthesia and facilitating faster recovery. Local anesthesia is generally safe, but like any medical intervention, it carries potential risks and side effects. The complications related to local anesthetics can be assessed in terms of neurological, vascular, local, systemic, and neurological. In this review article, we discussed the neurological complications of local anesthesia related to the ophthalmic nerve, maxillary nerve, mandibular nerve, branches of the trigeminal nerve, and facial nerve. These include diplopia, ptosis, paralysis of the eye, blindness, paresthesia, trismus, soft tissue lesions, edema, hematoma, facial blanching, infection, allergy, overdose, neuralgia, facial palsy, etc.

Adverse effects following dental local anesthesia: a literature review

Local anesthesia is indispensable in dentistry. Worldwide, millions of local anesthetic injections are administered annually, and are generally considered safe invasive procedures. However, adverse effects are possible, of which dentists should be aware of. This scoping review aimed to provide an extensive overview of the reported literature on the adverse effects of dental local anesthesia. The types of papers, what is reported, and how they are reported were reviewed. Additionally, the incidence and duration of adverse effects and factors influencing their occurrence were also reviewed. An electronic search for relevant articles was performed in PubMed and Embase databases from inception to January 2, 2020. The titles and abstracts were independently screened by two reviewers. The analysis was narrative, and no meta-analysis was performed. This study included 78 articles. Ocular and neurological adverse effects, allergies, hematomas, needle breakage, tissue necrosis, blanching, jaw ankylosis, osteomyelitis, and isolated atrial fibrillation have been described. Multiple adverse effects of dental local anesthesia have been reported in the literature. The results were heterogeneous, and detailed descriptions of the related procedures were lacking. Vital information concerning adverse effects, such as the dosage or type of anesthetic solution, or the type of needle used, was frequently missing. Therefore, high-quality research on this topic is needed. Finally, the adverse effects that are rarely encountered in real-world general practice are overrepresented in the literature.

Management of patients with allergy to local anesthetics: two case reports

Lidocaine is the most commonly used local anesthetic (LA) agent in various dental as well as oral and maxillofacial procedures. Although rare, adverse effects and allergic reactions to lidocaine have been reported. In patients with suspected allergy to LA or a history of such reaction, careful history-taking and allergy testing should be performed to choose an alternative LA agent to avoid any adverse effects. Here, we present two cases of delayed hypersensitivity reaction to lidocaine, wherein the patients presented with erythema, edema, and itching. Intradermal testing confirmed allergic reaction to lidocaine, and the patients underwent successful dental treatment using an alternative LA agent. This report highlights the importance of allergy testing prior to LA use considering the serious consequences of allergy to these agents and describes the management of such patients using an alternative LA agent.

Adverse reaction to local anaesthetics: Is it always allergy?

OBJECTIVE

Local anaesthetics are very commonly used drugs in dentistry, and people who undergo procedures with local anaesthetics often refer adverse reactions that are not of allergic origin. Considering that in dentistry contact with allergens is very frequent, it is essential to assess the real incidence of allergy to local anaesthetics.

SUBJECTS AND METHODS

We evaluated a group of 159 patients in whom adverse reaction occurred after procedures with local anaesthetics.

RESULTS

The reactions between allergy to local anaesthetic (immediate and delayed) and certain symptoms presented by patients were investigated. Allergy to latex and chlorexidine were investigated in all patients. Only one patient, who previously presented a constant erythema at the wrist after procedure with local anaesthetics, was positive to Mepivacaine patch test. Two patients were positive to latex and one to chlorexidine.

CONCLUSIONS

The main finding of this study was that a reaction registered in the medical history and reported by a patient is rarely allergic but the use of vasoconstrictors or emotional factors may account for it. However, a complete allergological investigation is necessary for a correct diagnosis and future management.

Knowledge and attitude toward anaphylaxis during local anesthesia among dental practitioners in Chennai - a cross-sectional study

Objective

Anaphylaxis is one of the local anesthetic dental emergencies that lead to morbidity and mortality. Hence, this study aimed to assess the knowledge and attitude of dental practitioners in Chennai toward managing anaphylaxis in patients who are given local anesthesia.

Participants and methods

Seventeen questions were formulated regarding anaphylaxis reactions and its treatment. The questions were given to a random selection of dentists practicing in private clinics in Chennai.

Results

Two hundred dentists responded to the questionnaire. The results indicated that the majority of the participants had knowledge of one or more symptoms relating to anaphylaxis. However, none of the participants demonstrated that they knew about all symptoms relating to anaphylaxis. The results also did not vary with age. Only 62% of the dentists surveyed were equipped with emergency kits in their clinic.

Conclusion

The present study has revealed the lack of knowledge among dentists in Chennai in relation to anaphylactic reactions and its management. Knowledge of practicing dentists in this area can be increased by providing continuing education programs consisting of workshops and hands-on courses.

Allergic Reactions to Dental Materials-A Systematic Review

INTRODUCTION

Utility of various dental materials ranging from diagnosis to rehabilitation for the management of oral diseases are not devoid of posing a potential risk of inducing allergic reactions to the patient, technician and dentist. This review aims to develop a systematic approach for the selection and monitoring of dental materials available in the market thereby giving an insight to predict their risk of inducing allergic reactions.

MATERIALS AND METHODS

Our data included 71 relevant articles which included 60 case reports, 8 prospective studies and 3 retrospective studies. The source of these articles was Pub Med search done with the following terms: allergies to impression materials, sodium hypochlorite, Ledermix paste, zinc oxide eugenol, formaldehyde, Latex gloves, Methyl methacrylate, fissure sealant, composites, mercury, Nickel-chromium, Titanium, polishing paste and local anaesthesia. All the relevant articles and their references were analysed. The clinical manifestations of allergy to different dental materials based on different case reports were reviewed.

RESULTS

After reviewing the literature, we found that the dental material reported to cause most adverse reactions in patients is amalgam and the incidence of oral lichenoid reactions adjacent to amalgam restorations occur more often than other dental materials.

CONCLUSION

The most common allergic reactions in dental staff are allergies to latex, acrylates and formaldehyde. While polymethylmethacrylates and latex trigger delayed hypersensitivity reactions, sodium metabisulphite and nickel cause immediate reactions. Over the last few years, due to the rise in number of patients with allergies from different materials, the practicing dentists should have knowledge about documented allergies to known materials and thus avoid such allergic manifestations in the dental clinic.

Cardiovascular tolerance of intravenous lidocaine in broiler chickens (Gallus gallus domesticus) anesthetized with isoflurane

OBJECTIVE

To determine the cardiovascular effects of lidocaine infused intravenously (IV) in broiler chickens.

STUDY DESIGN

Two phase study: Phase 1, randomized up-and-down study to determine effective dose 50 (ED50) for lidocaine; Phase 2, prospective randomized study to determine the cardiovascular effects of lidocaine.

ANIMALS

Seventeen Ross-708 broiler chickens (Gallus gallus domesticus) [11 chickens (Phase 1) and 6 chickens (Phase 2)], weighing 2.6-4.3 kg.

METHODS

After induction of anesthesia with isoflurane and placement of monitoring equipment including invasive blood pressure, chickens were administered lidocaine IV. During Phase 1, using an up-and-down design, each animal received a variable dose selected based on the response of the previous animal. During Phase 2, each animal was administered 6 mg kg(-1) of lidocaine IV over 2 minutes. Clinically irrelevant cardiovascular effects were defined as a relative decrease of heart rate (HR) and mean blood pressure (MAP) <30% subsequent to IV lidocaine administration. The ED50 was defined as the dose rate that would cause clinically irrelevant cardiovascular depression in 50% of the population.

RESULTS

During Phase 1, using an up-and-down study design (n = 11), the ED50 of lidocaine was determined to be 6.30 mg kg(-1) and 6.22 mg kg(-1) (95% confidence interval, 5.30-7.13 mg kg(-1)), when calculated by Dixon's up-and-down method, and logistic regression, respectively. During Phase 2, following infusion of lidocaine (6 mg kg(-1)), no clinically relevant effects on HR or MAP were detected in any animal.

CONCLUSIONS AND CLINICAL RELEVANCE

Previous reports state that the dose of lidocaine used in birds should be ≤4 mg kg(-1). In this study, 6 mg kg(-1) of lidocaine injected IV was not associated with adverse cardiovascular effects. These results suggest that the dose of 4 mg kg(-1) can be exceeded, at least in chickens, and opens the possibility of other therapeutic uses for lidocaine in birds.

Study on patients who underwent suspected diagnosis of allergy to amide-type local anesthetic agents by the leukocyte migration test

BACKGROUND

There are problems in diagnosis of allergy to amide-type local anesthetic agents (ALAs), because definitive diagnosis is not obtained by in vivo tests, which are used for the diagnosis. Consequently, patients may be exposed to risk. There are few diagnoses based on in vitro tests, and there are almost no relevant studies.

METHODS

Authors examined involvement of allergic reaction using the leukocyte migration test (LMT) through multiple standpoints in 43 patients who underwent suspected diagnosis of allergy to ALAs.

RESULTS

Rate of LMT-positives was 54%, and especially the positive rate of lidocaine hydrochloride preparations was significantly high. In 15 positives to lidocaine hydrochloride preparations, all cases were indicated as positive in a test with drugs containing antiseptic agent, but only 3 cases were indicated as positive in a test with lidocaine hydrochloride alone. In addition, test with paraben was conducted in 4 cases; 2 cases were confirmed as positive. In relevance of histories of drug or food allergies, development rates of ALAs-allergies were the highest in both allergies, and were 35% and 13%, respectively.

CONCLUSIONS

There is a high possibility that these adverse reactions were caused by pseudoallergy to drug. Even by allergic reactions, it was assumed that 80% of them might be caused by antiseptic agents such as paraben. In addition, it was suggested that ALAs, especially lidocaine hydrochloride preparations have high antigenicity (sensitizing property). Furthermore, it was considered that patients with past history of drug or food allergies have a high potential for manifestation of the reactions.

Food production and processing considerations of allergenic food ingredients: a review

Although most consumers show no adverse symptoms to food allergens, health consequences for sensitized individuals can be very serious. As a result, the Codex General Standard for the Labelling of Prepackaged Foods has specified a series of allergenic ingredients/substances requiring mandatory declaration when present in processed prepackaged food products. Countries adhering to international standards are required to observe this minimum of eight substances, but additional priority allergens are included in the list in some countries. Enforcement agencies have traditionally focused their effort on surveillance of prepackaged goods, but there is a growing need to apply a bottom-up approach to allergen risk management in food manufacturing starting from primary food processing operations in order to minimize the possibility of allergen contamination in finished products. The present paper aims to review food production considerations that impact allergen risk management, and it is directed mainly to food manufacturers and policy makers. Furthermore, a series of food ingredients and the allergenic fractions identified from them, as well as the current methodology used for detection of these allergenic foods, is provided.

Allergic reactions to local anesthetics in dental patients: analysis of intracutaneous and challenge tests

Some dental patients have histories of adverse reactions to local anesthesia. The aim of the present study was to investigate the frequency of allergy to local anesthetics of dental patients who had histories of adverse reactions to local anesthesia based on the results of allergy tests in our institute over a period of 5 years. We investigated the past medical records of dental patients retrospectively, and twenty patients were studied. Three of the 20 showed a positive or false-positive reaction in the intracutaneous test, and one patient showed a false-positive reaction in the challenge test. Our results suggest that the frequency of allergy to local anesthetics is low even if patients have histories of adverse reactions to local anesthesia. However, allergy tests of local anesthetics should be performed in patients in whom it is uncertain whether they are allergic.

Approach to patients with suspected hypersensitivity to local anesthetics

Adverse reactions to local anesthetics are relatively common, but true IgE-mediated hypersensitivity is extremely rare. Fortunately, the vast majority of adverse reactions occur via nonimmunologic means, but considerable confusion still exists among providers. We conducted a review of the literature to determine if earlier estimates of IgE-mediated allergy are consistent with current reports and whether current management strategies are consistent with these findings. We identified several confounding variables involved in the evaluation, including the roles of preservatives/additives, epinephrine, latex, and inadequate testing procedures. These problems may cause significant diagnostic challenges for clinicians. It is in fact much more likely that there is an alternate diagnosis, and in many cases clinicians can begin the evaluation in the office. When local anesthetic allergy is still suspected, the patient should be referred to an allergist for testing to determine if the suspected culprit drug can be safely used, or, if necessary, identify a suitable alternative.

Long-term absence of sensitization to mepivacaine as assessed by a diagnostic protocol including patch testing

BACKGROUND

Prospective assessment of non-reactivity to local anaesthetics is a frequent reason for allergy consultation.

OBJECTIVES

To investigate the clinical profiles of subjects referred for allergy evaluation; to prospectively reduce the frequency of evaluation by assessing the persistence, during clinical use, of non-reactivity to contaminant/additive-free mepivacaine; and to determine the usefulness of a diagnostic protocol involving patch testing.

METHODS

In a prospective study, 198 consecutive patients underwent collection of clinical data, skin prick tests and patch tests using allergens/antigens relevant for the investigation, and an intradermal/subcutaneous challenge procedure using contaminant/additive-free mepivacaine, as appropriate. Patients were followed up for 3 years for assessment of non-reactivity persistence using the same diagnostic protocol.

RESULTS

Only one-third of the patients had a history of previous adverse local anaesthetic reactions. Absence of sensitization to contaminant/additive-free mepivacaine persisted in all subjects completing the follow-up. Controlled challenge with mepivacaine was negative in 196 patients with both negative specific skin prick tests and patch tests but it was eventful in two subjects with positive specific patch tests. A few subjects displayed positive skin prick tests and/or patch tests for latex and/or additives.

CONCLUSIONS

A few patients had a relevant history for potential local anaesthetic-induced adverse reactions. Upon assessment of absence of sensitization and reactivity, contaminant/additive-free mepivacaine could safely be given for as long as 3 years. The patch testing was shown to be useful and safe for prediction of challenge outcomes. True allergic reactions to contaminant/additive-free mepivacaine were not observed in our patient series.

Adverse reaction to dental local anaesthetic injection--'allergy' is not the cause

OBJECTIVE

To investigate patients considered to have experienced allergic reactions to local anaesthetics administered for dental treatment.

SETTING

Dental facility within a general hospital.

PROCEDURE

Skin and intra-oral challenge tests.

RESULTS

No patients were found to be allergic to lignocaine or prilocaine. The most likely causes of the adverse reactions were found to be psychogenic.

CONCLUSION

Although allergy to lignocaine (and the other amide anaesthetic agents used in dentistry) is known to be extremely rare, it continues to be suggested as a cause when adverse reactions to dental injections occur. Psychogenic reactions are the main causes of untoward events, and some can be alarming. A smaller proportion of adverse responses can be attributed to (avoidable) intravascular injections. Adverse reactions can be reduced if injections are administered carefully.

Drug management in skin surgery

Lidocaine (lignocaine) 1% with epinephrine (adrenaline) 1:200,000 (maximum dose 40mL) is the agent of choice in skin surgery. It can be used at all sites except the fingers, toes and penis, where epinephrine should be avoided. Epinephrine-induced vasoconstriction delays local anaesthetic clearance, thus prolonging its effect and, by reducing peak blood lidocaine concentrations, enables a higher maximum dose to be used. Adding epinephrine, however, introduces the possibility of a drug interaction with tricyclic antidepressants and nonselective beta-blockers. Also, injection pain is greater because of the acidic sodium metabisulphite that has to be added to prevent epinephrine oxidation. Injection pain can be reduced by buffering the solution using sodium bicarbonate. There are no drug interactions that prevent the use of plain lidocaine: injection pain is least with 0.5% solutions. Injection of large volumes of very dilute lidocaine solutions (tumescent anaesthesia) enables higher maximum doses of lidocaine to be tolerated and large areas to be anaesthetised by infiltration. Amethocaine gel is a faster acting and more effective topical anaesthetic compared with eutectic lidocaine-prilocaine cream, but is a topical sensitiser. In high risk patients, prophylactic antibiotics should be given to prevent bacterial endocarditis when operating on infected lesions and on potentially colonised crusted lesions in high-risk patients (i.e. those with prosthetic heart valves). Wound infections following surgery on infected skin lesions can be prevented by the prophylactic use of mupirocin ointment. Aspirin-induced inhibition of platelet adhesion results in bleeding complications in approximately 15% of skin surgery patients receiving aspirin. Patients whose bleeding time is > 8 minutes are particularly at risk, and aspirin should be stopped at least 7 days prior to surgery in these patients. Aspirin can be continued in other patients without serious bleeding complications.

Local anesthetics

BACKGROUND

Dermatology is dependent upon the effects of local anesthetics for diagnostic and therapeutic interventions. A working knowledge of the drugs' actions and interactions is necessary for anyone aspiring to optimize the benefits derived from the use of local anesthetic agents.

OBJECTIVE

This article reviews nerve physiology, pharmacology, classification of local anesthetics, adverse reactions (toxic, drug, allergic), local anesthetic use in pregnancy, alternatives to the "-caine" anesthetics, methods for reducing the pain of infiltration, and new agents under development.

CONCLUSION

Local anesthetics are safe and effective. With the understanding of the actions and interactions of this class of drugs, maximum patient safety and satisfaction can be achieved.

Allergic urticaria and angioedema caused by a hemostatic sponge of bovine fibrin used in tooth extraction

We report the case of a 54-year-old woman with no history of atopic diseases or drug allergies who developed a generalized anaphylactic reaction with urticaria and angioedema a few hours after tooth extraction. The skin scratch and RAST tests demonstrated IgE-mediated hypersensitivity to the product Hémofibrine, a hemostatic sponge made of bovine fibrin. Of all RAST controls, only one serum with known positivity to bovine serum albumin (BSA) showed a low degree of positivity to Hémofibrine. Bovine fibrin should be added to the list of medical products that can elicit allergic reactions following dental treatment.

Long-term evaluation of usefulness of skin and incremental challenge tests in patients with history of adverse reaction to local anesthetics

A variety of adverse reactions to local anesthetics has been described, some of which are thought to be allergic. Different protocols of prick and intradermal skin tests as well as subcutaneous challenge tests are used to select a local anesthetic which can safely be used. Their long-term effectiveness has not yet been assessed. Twenty-eight patients with a history of adverse reaction to local anesthetics were evaluated over a 3-year period. Loss of consciousness occurred in eight patients, skin reaction in nine, and vagal symptoms in eight. Various reactions were recorded in the remaining three patients. Rapid spontaneous recovery was the rule, suggesting that immediate allergic reaction and, in particular, anaphylactic reaction were unlikely. Investigation allowed the selection of a tolerated anesthetic in all cases. Reexposure occurred in 19 patients 16-50 months after evaluation and 6.8 +/- 5.5 years after the first reaction. No patient presented a second reaction. In conclusion, adverse reactions to local anesthetics seem to be, in most cases, not allergic in nature. Evaluation protocols are effective in selecting an agent susceptible to tolerance, but are time consuming. However, they probably contribute to an important reassurance effect that is likely to increase tolerance to subsequent local anesthetic administration. Simplification of the protocols and better patient selection are proposed.

Sulfite contact allergy

In the last 2 years, 2,894 consecutive eczematous patients were patch tested with sodium metabisulfite 1% pet. Positive reactions were elicited in 50 subjects (1.7%). All 50 patients were also positive to potassium metabisulfite 1% pet. and sodium bisulfite 1% and 5% pet., while only 2 of them were positive to sodium sulfite 1% pet. Prick tests and intradermal tests with a sodium metabisulfite solution (10 mg/ml) were negative. No flare-ups of dermatitis or patch test were provoked by oral challenge with 30 mg and 50 mg of sodium metabisulfite. The dermatitis was taken to be occupational in 7 cases. In only 5 out of 43 non-occupational cases was the positive reaction considered relevant.

The rise in latex allergy: implications for the dentist

The ease with which latex allergies would develop was not anticipated when health care professionals began wearing examination gloves on a regular basis. Responses to the rise in latex allergies have been initiated by several agencies. These responses, cases of allergic reactions and definitions of allergy are discussed.

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.

Local anesthetic intolerance due to metabisulfite

The case of a 40-year-old woman with severe edema of the face and neck after the injection of a local dental anesthetic is presented. The reaction is attributed to the presence of sodium metabisulfite, and antioxidant, in the local anesthetic. Both the anesthetic and the sodium metabisulfite gave a delayed positive patch-test response.

[Severe complications related to metabisulfites]

Metabisulfite intolerance is encountered in 8 p. 100 of cases of extrinsic asthma and in 20 p. 100 of cases of the "aspirin triad" with nasosinusal polyposis, asthma and aspirin sensitivity. The possibility that anaphylactoid shock or acute severe asthma leading to status asthmaticus, might be related to sulfite sensitivity must be well known. Two case reports are set out. The first observation is that of a 35-year-old woman suffering from intrinsic asthma with alcohol intolerance, who developed status asthmaticus a few minutes after intravenous administration of Doxycycline associated with a metabisulfite preservative. The other 33-year-old patient presented with an acute bronchospasm in the course of a fiberoscopy using Lidocaine associated by mishap with epinephrine, as local anesthetic. The authors point to the miscellaneous drugs containing sulfites, that are employed in asthmatics by different routes, i.e. parenteral, oral, inhalational and other local treatments. Heavy metabisulfite intake may also arise from daily alcohol consumption. Sulfite intolerance could contribute to the persistence of chronic inflammatory processes in bronchial asthma and therefore should be systematically investigated.

Hypersensitivity reactions to food additives

Only seldom have food additives been shown to cause true allergic (immunological) reactions. Adverse effects due to various pharmacological or other mechanisms are much more common. The individual tolerance may be decreased for one reason or another, and may fluctuate from time to time. Many patients suffering from food additive reactions have atopic constitutions and such clinical symptoms as flexural dermatitis, rhinitis and asthma. The most important skin symptoms caused by food additives are urticaria, angioneurotic edema, and contact urticaria. Azo dyes, benzoic acid and several other common food additives may aggravate or, more rarely, even cause urticaria. Spices are one of the most common causes of immunological contact urticaria. Non-immunological contact urticaria is produced by numerous spices, benzoic acid, sorbic acid, cinnamic acid, and many essential oils. Asthma and rhinitis are the main hypersensitivity symptoms in the respiratory tract, and azo dyes, benzoic acid, and sulfitic food additives are the most common causative agents. Systemic and respiratory reactions to food colorants and benzoates have been claimed to occur more frequently in acetylsalicylic acid- (ASA-)sensitive patients than in non-reactors. Hypersensitivity reactions in organs other than the skin and respiratory tract are rare or poorly documented. Psychological factors play an essential role in both food and food additive reactions.

Allergy to local anesthetics: comparison of patch test with prick and intradermal test results

The interrelation between immediate and delayed hypersensitivity reactions to local anesthetics is poorly understood. Especially, the relevance of positive patch test reactions to local anesthetics with regard to the compatibility of injected local anesthetics is unclear. We therefore subjected 104 patch test-positive probands to prick and intradermal tests with seven local anesthetic agents. All prick tests were negative. Only 14 patients showed positive reactions in intradermal tests: 11 with the ester local anesthetic procaine, one with the amide local anesthetic butanilicaine, and two with both. Procaine yielded both immediate and delayed reactions; butanilicaine, only immediate reactions. All other local anesthetics showed negative reactions. It is concluded that in patients with positive patch test reactions to local anesthetics and negative history of anaphylactoid reactions, positive skin test reactions to intradermal application are rare and that, therefore, the risk of anaphylactic reactions to injection anesthesia with amide local anesthetics, except butanilicaine, appears low in these patients.

Sulfite hypersensitivity. A critical review

Sulfiting agents (sulfur dioxide and the sodium and potassium salts of bisulfite, sulfite, and metabisulfite) are widely used as preservatives in foods, beverages, and pharmaceuticals. Within the past 5 years, there have been numerous reports of adverse reactions to sulfiting agents. This review presents a comprehensive compilation and discussion of reports describing reactions to ingested, inhaled, and parenterally administered sulfite. Sulfite hypersensitivity is usually, but not exclusively, found within the chronic asthmatic population. Although there is some disagreement on its prevalence, a number of studies have indicated that 5 to 10% of all chronic asthmatics are sulfite hypersensitive. This review also describes respiratory sulfur dioxide sensitivity which essentially all asthmatics experience. Possible mechanisms of sulfite hypersensitivity and sulfur dioxide sensitivity are discussed in detail. Sulfite metabolism and the role of sulfite oxidase in the detoxification of exogenous sulfite are reviewed in relationship to the etiology of sulfite hypersensitivity.