Clinical-haematological changes and predictors of severity in acute food protein-induced enterocolitis syndrome reactions at oral food challenge: a multicentre observational study.

BACKGROUND: Oral food challenge (OFC) is the gold standard for diagnosis of acute Food Protein-Induced Enterocolitis Syndrome (FPIES). No diagnostic/prognostic biomarkers are available, and OFC assessment criteria are not validated. OBJECTIVE: To assess clinical-haematological changes and predictors of severity of FPIES reactions at OFC. METHODS: Observational multicentre prospective study. Children aged 0-18 years diagnosed with acute FPIES were recruited at follow-up OFC in 12 tertiary centres in Spain and Italy. OFC Outcomes (as positive/negative/inconclusive and mild/moderate/severe) were assessed based on published '2017 FPIES Consensus' criteria. Clinical characteristics were recorded, and full blood count was done at baseline, reaction onset and 4 hours later. Regression analysis was performed to assess predictors of severe reactions at OFC. RESULTS: 81 children had positive OFC (mild in 11% (9/81), moderate in 61% (49/81), severe in 28% (23/81)). Increase in neutrophils and reduction in eosinophils, basophils and lymphocytes was observed (P-value<0.05). OFC was inconclusive in 19 cases despite objective signs or neutrophilia. Regression analysis showed a 2-day OFC protocol where only 25% of an age-appropriate portion is given on day 1 (not gender, age, culprit food, cumulative dose and previous reaction severity) was associated with reduced odds of severe reaction compared to giving multiple doses in a single day. CONCLUSION: Distinct haematological changes may help support FPIES diagnosis. Current OFC assessment criteria may not capture the broad spectrum of acute FPIES presentations. This 2-day protocol may associate a reduced risk of severe reactions. Future work should aim to develop safer OFC and non-OFC diagnostics for FPIES.

Authors' reply - anaphylactic shock with methylprednisolone, Kounis syndrome and Hypersitivity to corticosteroids: a clinical paradox.

In our letter, we comment the paper of Kounis et al., that highlights a poor-known clinical entity determined by systemic use of corticosteroids, the so-called "Kounis syndrome type I". We appreciated and shared the intent of Authors to treat the important issue of high risk of adverse drug reaction in patients with atopic diathesis and we confirm the need to administer corticosteroids with caution in patients suffering from allergic disease.

Cross-reactivity and Tolerability of Ertapenem in Patients With IgE-Mediated Hypersensitivity to ß-Lactams.

BACKGROUND AND OBJECTIVE: Administration of carbapenems to ß-lactam-allergic patients has always been considered potentially harmful because of a 47.4% rate of cross-reactivity to imipenem reported in a single study. Nevertheless, recent studies have shown that the rate of cross-reactivity of imipenem and meropenem with penicillins is lower than 1%. The aim of this study was to evaluate the possibility of using ertapenem in patients with an established IgE-mediated ß-lactam allergy. PATIENTS AND METHODS: We studied all participants who came to our allergy unit and had a clinical history of immediate hypersensitivity reactions to ß-lactams. The inclusion criteria were a positive skin test result to at least 1 ß-lactam molecule and/or positive specific IgE (when available). All participants underwent immediate-type skin tests with several ß-lactam molecules including ertapenem. Challenges with intravenous ertapenem were performed on 2 different days in patients with negative skin test results. RESULTS: We examined 49 patients with a clinical history of immediate reactions to ß-lactams. All the patients had positive skin tests and/or positive specific IgE to at least 1 ß-lactam reagent and negative carbapenem skin tests. Thirty-six patients agreed to undergo the challenges and 35 tolerated the full dose of ertapenem. CONCLUSIONS: The practice of avoiding carbapenems in patients with ß-lactam allergy should be abandoned considering the very low rate of cross-reactivity. ß-Lactam-allergic patients who need ertapenem therapy should undergo skin tests and, if negative, a graded challenge to assess tolerability.

Cross-reactivity and tolerability of Ertapenem in patients with IgE-mediated hypersensitivy to Beta-lactams

Background and Objective: Administration of carbapenems to β-lactam-allergic patients has always been considered potentially harmful because of a 47.4% rate of cross-reactivity to imipenem reported in a single study. Nevertheless, recent studies have shown that the rate of cross-reactivity of imipenem and meropenem with penicillins is lower than 1%. The aim of this study was to evaluate the possibility of using ertapenem in patients with an established IgE-mediated β-lactam allergy. Patients and Methods: We studied all participants who came to our allergy unit and had a clinical history of immediate hypersensitivity reactions to β-lactams. The inclusion criteria were a positive skin test result to at least 1 β-lactam molecule and/or positive specific IgE (when available). All participants underwent immediate-type skin tests with several β-lactam molecules including ertapenem. Challenges with intravenous ertapenem were performed on 2 different days in patients with negative skin test results. Results: We examined 49 patients with a clinical history of immediate reactions to β-lactams. All the patients had positive skin tests and/or positive specific IgE to at least 1 β-lactam reagent and negative carbapenem skin tests. Thirty-six patients agreed to undergo the challenges and 35 tolerated the full dose of ertapenem. Conclusions: The practice of avoiding carbapenems in patients with β-lactam allergy should be abandoned considering the very low rate of cross-reactivity. β-Lactam-allergic patients who need ertapenem therapy should undergo skin tests and, if negative, a graded challenge to assess tolerability (AU)

Introducción y Objetivo: Siempre se ha considerado peligrosa la administración de carbapenems a pacientes alérgicos a betalactámicos por la presencia de reactividad cruzada en el 47,4% de los casos descrita en un estudio previo. Sin embargo, estudios recientes han mostrado que la reactividad cruzada de imipenem y meropenem con penicilinas es inferior al 1%. El objetivo de este estudio es valorar el uso de ertapenem en pacientes diagnosticado de alergia IgE mediada a betalactámicos. Pacientes y Métodos: Se incluyeron todos los pacientes que acudieron a nuestra unidad de Alergia con historia clínica de alergia inmediata a betalactámicos. Los criterios de inclusión fueron prueba cutánea positiva con al menos un betalactámico y/o IgE específica positiva (cuando estuviese disponible). Se realizaron pruebas cutáneas con betalactámicos, incluyendo ertapenem, con lectura inmediata en todos los pacientes. Se realizaron pruebas de provocación endovenosas con ertapenem en los pacientes con pruebas cutáneas negativas frente al mismo en dos días diferentes. Resultados: Se incluyeron 49 pacientes con historia clínica de alergia inmediata a betalactámicos. Todos los pacientes tenían pruebas cutáneas positivas y/o IgE específica positiva al menos a uno de los betalactámicos así como prueba cutánea negativa con carbapenémicos. Treinta y seis pacientes aceptaron la realización de pruebas de provocación con ertapenem que fueron tolerados por treinta y cinco de dichos pacientes. Conclusión: El hecho de recomendar evitar carbapenems en pacientes con alergia a betalactámicos debería ser abandonado, dada la baja reactividad cruzada que presentan. En los pacientes con alergia a betalactámicos que necesiten ertapenem se deberían realizar pruebas cutáneas con el fármaco y en caso de ser negativas, realizar un test de exposición progresiva para confirmar su tolerancia (AU)

Cross-reactivity and tolerability of cephalosporins in patients with cell-mediated allergy to penicillins.

BACKGROUND AND OBJECTIVE: 13-Lactams are the most commonly used antibiotics but they can cause hypersensitivity reactions. We sought to estimate cross-reactivity and tolerability of cephalosporins in patients with cell-mediated allergy to penicillins. METHODS: We studied 97 patients with a clinical history of nonimmediate reactions to a penicillin and a positive patch test result to at least 1 of the penicillins tested. All patients also underwent patch testing with several cephalosporins. Patients with a negative patch test to a cephalosporin underwent test dosing in order to assess tolerability. RESULTS: We recorded 129 reactions. The most commonly involved drugs were aminopenicillins, and the most widely reported symptoms were delayed urticaria and maculopapular exanthema. Seventeen patients had positive patch test results for cephalosporins, mostly for cephalexin (n=10), cefaclor (n=9), and cefuroxime axetil (n=5). All the patients-except 4 who experienced an exanthema after the challenge test with cephalexin-tolerated a therapeutic dose of the cephalosporin tested without any adverse effects. CONCLUSIONS: Our data show that cross-reactivity between penicillins and cephalosporins may be as high as 10.9% for first-generation cephalosporins and 1.1% for third-generation cephalosporins, possibly due to the involvement of similar side chains. Patch tests are a useful diagnostic tool to assess cross-reactivity, but a graded challenge is mandatory because a negative patch test does not always mean tolerability.

Cross-reactivity and tolerability of cephalosporins in patients with cell-mediated allergy to penicillins

Background and objective: b-Lactams are the most commonly used antibiotics but they can cause hypersensitivity reactions. We sought to estimate cross-reactivity and tolerability of cephalosporins in patients with cell-mediated allergy to penicillins. Methods: We studied 97 patients with a clinical history of nonimmediate reactions to a penicillin and a positive patch test result to at least 1 of the penicillins tested. All patients also underwent patch testing with several cephalosporins. Patients with a negative patch test to a cephalosporin underwent test dosing in order to assess tolerability. Results: We recorded 129 reactions. The most commonly involved drugs were aminopenicillins, and the most widely reported symptoms were delayed urticaria and maculopapular exanthema. Seventeen patients had positive patch test results for cephalosporins, mostly for cephalexin (n=10), cefaclor (n=9), and cefuroxime axetil (n = 5). All the patients-except 4 who experienced an exanthema after the challenge test with cephalexin—tolerated a therapeutic dose of the cephalosporin tested without any adverse effects. Conclusions: Our data show that cross-reactivity between penicillins and cephalosporins may be as high as 10.9% for first-generation cephalosporins and 1.1% for third-generation cephalosporins, possibly due to the involvement of similar side chains. Patch tests are a useful diagnostic tool to assess cross-reactivity, but a graded challenge is mandatory because a negative patch test does not always mean tolerability (AU)

Introducción y objetivo: Los antibióticos betalactámicos son los más comúnmente utilizados y pueden ser responsables del desarrollo de reacciones de hipersensibilidad. Este estudio pretende estimar la reactividad cruzada y la tolerancia a las cefalosporinas en pacientes con alergia mediada por células a penicilinas. Métodos: Estudiamos 97 pacientes con historia clínica de reacciones no inmediatas a penicilina y que habían tenido una prueba de parche positiva al menos frente a una de las penicilinas testadas. También se realizó parche frente a alguna cefalosporina en todos ellos. Los pacientes con negatividad en esta prueba se sometieron a la prueba de tolerancia. Resultados: Se recopilaron 129 reacciones, la mayoría de los medicamentos implicados fueron aminopenicilinas, siendo los síntomas más frecuentes la urticaria de aparición tardía y el exantema máculo-papular. Diecisiete pacientes arrojaron resultados positivos en la prueba del parche a cefalosporinas, cefalexina (10 casos), ceflacor (9) y acetil-cefuroxima (5). Todos los pacientes excepto 4 (los cuales tuvieron un eccema tras la provocación con cefalexina), toleraron la dosis terapéutica de la cefalosporina probada sin ningún efecto dañino. Conclusiones: Según nuestros resultados, la reactividad cruzada entre penicilinas y cefalosporinas es de 10,9% para las cefalosporinas de primera generación y de 1,1% para las de tercera generación. Esto puede ser debido a las cadenas similares implicadas. La prueba del parche es una herramienta diagnóstica útil para evaluar la reactividad cruzada, pero necesita una provocación gradual, dado que una prueba del parche negativa no implica tolerancia (AU)

Gene expression profiling of patients with latex and/or vegetable food allergy.

BACKGROUND: The prevalence of individuals allergic to latex, exhibiting cross-hypersensitivity with plant-derived food has been frequently reported as the so-called latex-fruit syndrome. Nonetheless, molecular mechanisms underlying allergy to latex and/or fruit are poorly understood. AIM: The aims of this study were to identify candidate genes that may be associated with the pathogenesis of allergy to latex and/or vegetable food, and to assess if similar molecular pathways are involved in both types of hypersensitivity. MATERIALS AND METHODS: DNA microarray analysis was performed to screen the molecular profiles of peripheral blood mononuclear cells isolated from patients with allergy to latex, to fruit, or with latex-fruit syndrome, and from control healthy subjects. RESULTS: Molecular profiling identified an overlapping dataset of genes commonly regulated in all the atopic patients enrolled in this study, suggesting that similar molecular mechanisms are involved in the pathogenesis of allergy to the fruit and/or latex. Several regulators of the innate and acquired immunity reported to polarize the immunological response towards a Th2-mediated immune response were overexpressed in the patients. Evidences suggested that the expression of T-regulatory cells might be defective in allergic patients, as a consequence of a dysregulation of some inflammatory cytokines. Finally, several transcription factors that may be responsible for the Th1/Th2 imbalance were modulated in allergic patients. CONCLUSIONS: This study identified relevant genes that may help to elucidate the molecular mechanisms underlying allergic disease. Knowledges of critical targets, along with transcription factors regulating gene activity may facilitate the development of new therapeutic options.

The clinical meaning of positive latex sIgE in patients with food/pollen adverse reactions.

Natural rubber latex allergy (NRL-A) is an international problem of public health. About 50-60% of NRL-A patients may present adverse reactions after ingestion of cross-reacting vegetable foods. This condition, called "Latex-fruit Syndrome", is a matter of research. The aim of our study is to distinguish between clinical/subclinical latex-fruit syndrome and cross-sensitization to latex and food/pollen allergens on the basis of latex recombinant allergens. We studied 51 patients with food hypersensitivity and serological evidence of NRL sensitization. The subjects underwent an accurate allergological evaluation (skin prick test with latex, food and pollen extracts, specific IgE to latex and recombinant allergens, challenge provocation tests). The patients were divided in two groups: group A) 34 patients with clinical and serological latex and fruit/vegetable allergies; group B) 17 patients allergic to fruits/vegetables and/or pollens, with serological, but not clinical NRL-A. All the latex challenge tests resulted positive in group A patients and only two patients of group B presented positive cutaneous challenge tests. Moreover, specific IgE-antibodies were detected to rHev b 5, to rHev b 6.01, to rHev b 6.02 and to rHev b 8 (and other profilins) of group A patients, while in group B we observed a monosensitization to Hev b8, probably linked to a cross-sensitization to pollens and foods. At the present state of knowledge, we need a multi-parametric approach based on a combination of clinical history, diagnostic tests (CRD) and latex challenge tests to make diagnosis of latex-fruit syndrome.

Profilin desensitization in two patients with plant-derived food allergy.

Profilins are "panallergens", responsible for many cross-reactivities between inhalant, latex and plant-derived food allergens. We evaluated the effectiveness and the safety of sublingual desensitization treatment (SLIT) in two patients with allergic respiratory and food diseases. Skin prick tests, IgE and IgG4 assays to pollens, some plant-derived foods, profilin, non-lipid specific transfer protein and PR 10 proteins were performed. The patients also underwent double-blind placebo-controlled challenge (DBPCFC) with the culprit foods and profilin and then a SLIT with it. Both the patients had positive SPT, specific IgE and DBPCFCs with profilin and some vegetables referred in anamnesis. They therefore underwent SLIT with profilin extract. At the end of treatment, the patients had negative DBPCFCs with culprit foods and a decrease of specific IgE levels for profilin and vegetable foods. Profilin desensitization allowed our patients to manage their diet without restriction, eating several foods previously not tolerated.

Tolerability of aztreonam in patients with cell-mediated allergy to ß-lactams.

BACKGROUND: Cross-reactivity between aztreonam and ß-lactams is poor, but tolerability of aztreonam has been assessed in a few groups of patients suffering from IgE-mediated allergy to ß-lactams. The aim of this study was to assess the cross-reactivity of aztreonam with other ß-lactams and its tolerability in patients with cell-mediated allergy to these drugs. METHODS: We studied 78 patients with cell-mediated allergy to ß-lactams who underwent skin prick, immediate and delayed-reading intradermal tests as well as patch tests with penicilloyl-polylysine, minor determinant mixture, semi-synthetic penicillins, cephalosporins, aztreonam and imipenem. Patients with negative allergy testing with aztreonam underwent an intramuscular test dosing and were observed for 3 h. RESULTS: Our patients experienced 94 non-immediate reactions; delayed-onset urticaria (34 cases), maculopapular exanthema (13 cases), urticaria/angioedema (15 cases) and itching erythema (13 cases) were the most reported symptoms. Amoxicillin (35 cases), ampicillin (28 cases) and bacampicillin (18 cases) were the most involved drugs. All patients had a positive patch test and/or a positive delayed-reading intradermal test to at least 1 ß-lactam antibiotic and none had a positive patch or delayed-reading intradermal test to aztreonam. Then, 65 patients underwent intramuscular test dosing with aztroenam, and none of them had a clinical reaction. CONCLUSIONS: Our data confirm the lack of cross-reactivity between ß-lactams and aztreonam in patients with cell-mediated allergy to these drugs. Delayed-reading intradermal tests and patch tests with aztreonam represent a simple and rapid diagnostic tool to establish tolerability in ß-lactam-allergic patients.

Allergic and non-allergic drug hypersensitivity reactions in children.

Adverse drug reactions (ADR) are an important medical problem. The aim of this study is to investigate the clinical characteristics of children with ADR and to assess the tolerability of alternative drugs in children (under 16 yrs of age) with a history of ADR. We studied 278 children (132 males and 146 females). Patients were studied by recording personal history and performing in vivo skin testing, in vitro laboratory tests and challenge tests. Patients who had experienced mild adverse reactions underwent challenge tests without any premedication; patients with a clinical history of moderate reactions, received a premedication with sodium chromolyn 30 min before the oral challenge; patients with a clinical history of severe reactions or undergoing parenteral challenges, were given an antihistamine 30 minutes before. A total of 660 adverse events were reported with 126 different drugs involved. Antimicrobial agents were the most involved drugs (51.7%). Non-steroidal anti-inflammatory drugs were involved in 22.7% of episodes. The most reported symptoms were cutaneous. Allergy testing was negative in 272 patients. A diagnosis of drug allergy was reported for 6 patients. A total of 669 challenge tests were performed. 639 were negative at first attempt while 22 were positive. Eight were repeated using a different premedication and resulted negative. Hypersensitivity drug reactions in children are mainly non-allergic. A premedication with sodium cromolyn or with oral H1-antihistamines may be useful in preventing ADR.

Challenge tests in the diagnosis of latex allergy.

The aim of this study is to evaluate the sensitivity, specificity and safety of challenge tests and their usefulness in the diagnosis of latex allergy. Forty adult subjects (F/M = 34/6, aged 18-66 yrs) with a history of adverse reactions after latex exposure and positive prick test and/or specific IgE to latex were enrolled. They were compared with 20 control subjects. They underwent provocative (cutaneous, mucous-oral, sublingual, conjunctival, nasal, bronchial, vaginal) tests. Symptoms and drug scores were recorded for each patient during challenges. All patients reacted to at least one of the following: cutaneous, nasal and conjunctival tests. No systemic reactions requiring epinephrine occurred. Of the challenges, the vaginal test resulted as the safest, but it had low sensitivity and many limits related to the procedure. According to our data, bronchial and nasal tests had the highest sensitivity (76% and 82% respectively), and were more precise than other tests in determining latex exposure and symptoms, but the bronchial test also presented the highest rate of risk. Mucous and cutaneous tests resulted as the most reliable. For all the tests, specificity and positive predictive value were 100%. All control subjects resulted negative to all challenges. There were no statistically significant changes in skin and serologic tests between the first and second visits. Correlations between MIS and skin tests and between MIS and serum tests were not found. Challenges can be considered safe diagnostic procedures. Tests that most faithfully reproduce natural exposure, on the basis of a patient's history, are preferable.

Sublingual-oral rush desensitization to mixed cow and sheep milk: a case report.

We attempted an oral rush desensitization with mixed cow and sheep milk in a 6-year-old boy who had had adverse reactions to cow and goat milks. Skin prick tests and specific immunoglobulin (Ig) E to cow, sheep and goat milks were positive. The double-blind, placebo-controlled food challenge with cow milk was positive too. He underwent a 12-day sublingual-oral desensitization treatment with mixed cow and sheep milk. Specific IgE and IgG4 were measured. Open oral challenges with cow milk, sheep milk and sheep cheeses were also performed after the desensitization. At the end of the desensitizing treatment our patient could tolerate 120 mL of mixed milk. Specific IgE levels did not vary, whereas an increase of specific IgG4 concentrations was observed. Open oral challenges with cow and sheep milks and sheep cheeses were negative. Oral rush desensitization may represent an alternative approach to the treatment of food allergy in children.

Sublingual immunotherapy for latex allergy: tolerability and safety profile of rush build-up phase.

OBJECTIVE: Sublingual immunotherapy represents an efficient therapeutic tool for the management of latex allergic patients. Local and systemic adverse reactions are reported, and risk factors for those reactions are poorly understood. The aim of this study is to compare two different rush induction protocols (2-day and 3-day) in terms of safety and tolerability and effectiveness in reaching the maintenance dose. METHODS: Twenty-three outpatients (F/M = 18:5; 5-64 years of age), with latex allergy were randomly assigned to: Group 1 (2-day) and Group 2 (3-day). Adverse reactions were classified by their type and severity. RESULTS: Twenty-one subjects, 10 from Group 1 and 11 from Group 2, reached the maintenance dose, 70% of them without side effects. Seven adverse events were reported in Group 1: three were local (oral itching) and spontaneously remitted; four were systemic (Grade-2: two reactions; Grade-3: two reactions) and were effectively controlled with drugs. The protocol was interrupted in two cases because of recurrent reactions. No reactions were reported in Group 2. Age, gender, atopy, specific IgE, skin prick tests and sublingual challenge did not seem to influence the risk of side effects significantly. No significant modification of skin tests and specific IgE levels were reported in both groups. The cutaneous test turned negative in 16 patients, eight from Group 1 (80%) and eight from Group 2 (73%). The remaining patients (two from Group 1 and three from Group 2) showed a reduction of latex reactivity, in terms of symptom score (MIS: 2 vs. 0.5 in Group 1, 3 vs. 1 in Group 2). CONCLUSIONS: This study confirms the safety of rush induction. The 3-day protocol was better tolerated than the 2-day. Significant risk factors for the occurrence of adverse reactions were not identified. Only the type of protocol but not patient-related parameters seemed predictive of side-effects.

A clinical trial of oral hyposensitization in systemic allergy to nickel.

Nickel allergy is the most common contact allergy. Some nickel-sensitive patients present systemic (cutaneous and/or digestive) symptoms related to the ingestion of high nickel-content foods, which significantly improve after a specific low nickel-content diet. The etiopathogenetic role of nickel in the genesis of systemic disorders is, furthermore, demonstrated by the relapse of previous contact lesions, appearance of widespread eczema and generalized urticaria-like lesions after oral nickel challenge test. The aim of this study is to investigate the safety and efficacy of a specific oral hyposensitization to nickel in patients with both local contact disorders and systemic symptoms after the ingestion of nickel-containing foods. Inclusion criteria for the recruitment of these patients were (other than a positive patch test) a benefit higher than 80% from a low nickel-content diet and a positive oral challenge with nickel. Based on the previous experiences, our group adopted a therapeutic protocol by using increasing oral doses of nickel sulfate associated to an elimination diet. Results have been excellent: this treatment has been effective in inducing clinical tolerance to nickel-containing foods, with a low incidence of side effects (gastric pyrosis, itching erythema).

Oral rush desensitization with tomato: a case report.

Adverse food reaction in which no immunological mechanism is demonstrated should be termed nonallergic food hypersensitivity or food intolerance. We present the case of a 12-year-old girl with a clinical history of abdominal pain, nausea, and general malaise after tomato intake which completely remitted with antihistamines. The patient underwent a complete allergy evaluation: skin prick tests, serum specific IgE and IgG4 tests to tomato, and double-blind placebo-controlled food challenge. Skin prick tests and specific IgE to tomato were negative while the food challenge was positive. At the end of the workup, the patient underwent an oral rush desensitizing treatment. At the end of the treatment the patient could eat a maintenance dose of 100 g of tomato daily with no side effects at all. This successful result suggests that the oral desensitizing treatment can be used in patients with nonallergic food hypersensitivity.

Positive patch tests to Euro coins in nickel-sensitized patients.

BACKGROUND: Many efforts have been made to prevent nickel allergy, the most frequent contact allergy in industrialized countries, by identifying acceptable limits of exposure. Even though coins are not covered by the EU Nickel Directive, some authors suggest that nickel release from coins during handling may elicit contact dermatitis in nickel-allergic people. OBJECTIVES: To evaluate sensitivity to nickel released from coins in nickel-allergic patients and to verify whether nickel release from the new Euro coins may elicit stronger cutaneous reactivity than from old Italian lire coins. METHODS: Twenty-five nickel-allergic patients were patch tested with 1- and 2-Euro coins, 1-, 2- and 50-Euro cent coins, and 100 and 500 Italian lire coins. Ten healthy nonnickel-allergic control individuals were also tested. RESULTS: Nineteen patients had positive patch tests to 1- and 2-Euro coins. One was also positive to 1- and 2-Euro cent coins, four to 50-Euro cent coins, and 13 to the 500-lire coin. None had a positive patch test to the 100-lire coin. The number and degree of positive patch tests to coins were related to nickel content. CONCLUSIONS: Euro coins may be potentially more dangerous than old Italian coins. Coins containing little or no nickel should be chosen for coinage to prevent sensitization and to avoid exacerbation of contact dermatitis in nickel-allergic patients.