Atopy Patch Test Research Articles

Oat sensitization in children with atopic dermatitis: prevalence, risks and associated factors

Topical treatments of atopic dermatitis (AD) may be responsible for cutaneous allergies. Percutaneous sensitization to oat used in emollients/moisturizers has already been reported. Our objectives were to measure the prevalence of oat sensitization in AD children, to assess its relevance, and to look at related parameters. We recruited prospectively children with AD referred for allergy testing between June 2001 and December 2004. Atopy patch tests (APT) and skin prick tests (SPT) to oat proteins (1%, 3% and 5%) and to the European standard series were performed followed by oral food challenge (OFC) and repeated open application test (ROAT) in the oat-sensitized group. About 302 children were enrolled. Oat APT and SPT were positive in 14.6% and 19.2% of cases, respectively. Children under 2 years of age were more likely to have positive APT. In oat-sensitized children, OFC and ROAT were positive in 15.6% (five of 32) and 28% (seven of 25) of cases, respectively. Thirty-two percentage of oat cream users had oat-positive atopy patch test (APT) vs 0% in the nonusers group. Oat sensitization in AD children seen for allergy testing is higher than expected. It may be the result of repeated applications of cosmetics with oats on a predisposed impaired epidermal barrier. We suggest avoiding topical-containing oat proteins in infants with AD.

Pollen Grains Induce a Rapid and Biphasic Eczematous Immune Response in Atopic Eczema Patients

Introduction: Eczematous reactions to type I allergy-inducing antigens are documented in a subgroup of patients with atopic eczema. Yet, the underlying immunological mechanisms are not well understood. Material and Methods: To delineate the effect of native pollen grains on human skin of healthy and atopic individuals we performed patch tests (atopy patch test with native pollen grains, PPT). Nickel patch tests (NPT) served as an established model of contact dermatitis. Skin site biopsies were taken 6–96 h after allergen application and investigated immunohistochemically. Results: Histology of positive patch tests showed an influx of mononuclear cells (predominantly CD4+, CD25+, CD45RO+). This influx was detected earlier in the PPT reaction than in the immune response to nickel. A biphasic cytokine response could be detected in the PPT: IL-5 dominated in the early, IFN-γ in the late phase. The NPT was continuously dominated by IFN-γ. Dendritic cell subpopulations imitated the earlier kinetics of the mononuclear infiltrate. Discussion: Thus, pollen grains induce eczematous reactions in susceptible individuals. This reaction appears clinically and immunohistochemically similar to the contact hypersensitivity reaction to nickel but follows a faster kinetic and a biphasic course: Th2 and IgE in the early (24 h) and Th1 predominance in the late (96 h) phase.

Diagnosis of Food Allergy in Children: Toward a Standardization of Food Challenge

Adverse reactions to food represent a common complaint in childhood; however, only a small proportion of children have proven clinically relevant food allergy. The foods most commonly involved in food allergy are cow's milk, hen's eggs, peanuts, tree nuts, seeds, soy, wheat, fish, and crustaceans. The diagnostic workup of suspected food allergy includes the patient's history, skin prick testing, the measurement of food-specific immunoglobulin E antibodies, and, more recently, the atopy patch test. Because none of these parameters can accurately predict tolerance, the gold standard for diagnosing food allergy is still the double-blind, placebo-controlled food challenge. Although numerous efforts have been made to standardize the procedure, there is a need for improvement. This review presents the current status of the indication and performance of controlled oral food challenges in children with suspected food-related symptoms. It covers aspects of indications and contraindications, blinding, diet before the challenge, the practical performance, the handling of medication, the interpretation of test results, suitable locations for testing, safety considerations, and the procedure after a period of avoidance. Efforts to standardize oral food challenges to achieve the best possible decision on a diet are important to avoid an unnecessary diet that may be harmful to the child.

Food allergy and atopy patch tests - Authors' reply

Food allergy and atopy patch tests - Authors' reply

Determination of acid base balance and oil water partition coefficient of an atopy patch test of levofloxacin

Levofloxacin, a quinolone used in the treatment of an upper respiratory tract infection is involved in skin reactions. Patch tests are helpful for the aetiological diagnosis. Unfortunately, they are known for their lack of sensibility. A weak transcutaneous penetration due to the physicochemical characteristics of tested drugs is a well-known cause of false negative results but these characteristics are usually unknown. The aim of the present study was to evaluate physicochemical parameters by potentiometric method in order to optimize the transcutaneous penetration of a preparation for patch test. This method is applicable to a medium such as the preparation for patch test. In order to value the stability of the preparation, qualitative and quantitative analysis of the level of levofloxacin was effectuated. In our study, spectrophotometric and potentiometric data at T0 and six months later with the preparation showed the stability of the preparation. The proportions of non-ionized (45%) and ionized levofloxacin (55%) were not modified. Further experiments are needed to choose the minimal efficient dose of the suspected molecule able to detect a positive reaction in cases of allergic reaction. In addition, this method could be useful in qualitative and quantitative control of preparations made at hospital.

Food allergy and atopy patch tests

Food allergy and atopy patch tests

Diagnostic accuracy of the atopy patch test in children with food allergy‐related gastrointestinal symptoms

Little is known about the diagnostic accuracy of atopy patch tests (APT) in the clinical practice of pediatric gastroenterology. Moreover, APTs containing purified food extracts have recently become available, but their diagnostic accuracy is largely undefined. We evaluated the diagnostic accuracy of food challenge, skin prick test (SPT), serum specific IgE determination, and APT using fresh food and commercial food extracts in parallel in children referred for suspected food allergy-related gastrointestinal symptoms. Eighty-nine food challenges were performed in 60 patients (38 boys, median age 23 months, range 3-48 months): 31 tested positive for cow's milk (CM), 19 for hen's egg (HE), and two for wheat. Specific immunoglobulin E (IgE) determination, and SPT, respectively, were positive in 7/31 and 14/31 of patients with cow's milk allergy (CMA), and in 7/19 and 7/19 with HE allergy. The results of APT with fresh food vs a commercial assay were (1) CM: sensitivity: 64.5%vs 6.4%, specificity 95.8%vs 95.6%, positive predictive value (PPV) 95.2%vs 66.6% and negative predictive value (NPV) 67.6%vs 43.1%; (2) HE: sensitivity 84.2%vs 5.2%, specificity 100%vs 100%, PPV 100%vs 100% and NPV 75.0%vs 33.3%. Atopy patch test is a useful tool in the diagnostic work up of children with food-allergy-related gastrointestinal symptoms. The diagnostic accuracy of ATP was higher with fresh food than with commercial food extracts.

Eosinophilic esophagitis in adults and children: evidence for a food allergy component in many patients

Eosinophilic esophagitis is a recently recognized disorder receiving increasing attention. Patients present with symptoms of gastroesophageal reflux and are not responsive to standard or aggressive reflux medications. This article reviews all literature published in English from December 2005 to November 2006 from PubMed on the topic of eosinophilic esophagitis. Three articles have confirmed that food allergies are causative in more than 90% of patients. Three different diet strategies were used: elemental, elimination diet based on the prick-skin test, and the atopy patch test or removal of the six most common foods. The elemental diet had the highest success rate (> 95%), whereas the testing-based elimination diet (> 75%) and six-food elimination diet (> 70%) had lower success rates. There are no organized dietary trials in adults. Recent literature on pediatric patients with eosinophilic esophagitis confirms that nearly all patients respond to an elemental diet with resolution of symptoms and normalization of biopsies. Although diets based on testing or removal of the most common allergens showed success, they were less successful than a complete elimination diet. Unfortunately, there are very limited studies in adults that address this issue.

Unnecessary Milk Elimination Diets in Children with Atopic Dermatitis

Milk elimination diets are frequently adopted in the treatment of atopic dermatitis, although the real prevalence of clinically relevant food allergy remains unclear and reports from different authors are often in disagreement. We investigated the percentage of children allergic to cow's milk compared with the rate of milk exclusion diets in a group of patients with atopic dermatitis. We enrolled 206 children (79 girls, 127 boys), mean age 45.8 (4-68) months, affected by atopic dermatitis into our study. All children underwent radioallergosorbent test for casein, alpha-lactalbumin and beta-lactoglobulin, prick test, atopy patch test, and oral provocation test. Children were followed up at 1, 3, 6, and 12 months. Of the 206 patients, 20 were excluded from statistical analysis, leaving 186. Forty-five (24.2%) were on a milk elimination diet and 141 on a normal diet. Four patients on the milk-free diet (8.9%), accounting for 2.2% of all patients, were found to be allergic. In the others, milk reintroduction did not cause the disease to worsen during the follow-up period. No children on a normal diet were found to be allergic. Our results demonstrated an actual prevalence of cow's milk allergy in patients on milk elimination diets (4%) to be significantly lower than the number of patients prescribed such diets (24.2%)-confirming that this measure is being applied excessively.

Sensitization to the Yeast Malassezia Sympodialis Is Specific for Extrinsic and Intrinsic Atopic Eczema

The opportunistic yeast Malassezia sympodialis belongs to the normal cutaneous flora but can also cause IgE-mediated sensitization in patients suffering from atopic eczema (AE). We investigated 706 individuals by ImmunoCAPm70 and skin-prick tests with a crude M. sympodialis extract. In AE patients, we further performed skin prick tests, atopy patch tests, ELISA, and peripheral blood mononuclear cells proliferation assays with recombinant M. sympodialis allergens (rMala s 1 and 5-9). In 52/97 patients with AE-specific IgE against M. sympodialis was detectable. Almost no reactivity to M. sympodialis was seen in patients suffering from other allergic diseases (4/571) and no reactivity at all was seen in healthy controls (0/38). Skin tests showed variable recognition patterns against the different molecular structures with a predominant sensitization to rMala s 1, 5, 6, and 9, confirmed also by specific serum IgE to these allergens. Interestingly, IgE- and T-cell-mediated reactivity against M. sympodialis was also found in patients with the intrinsic form of AE. Thus, sensitization to M. sympodialis is specific for AE patients and occurs in both the extrinsic and intrinsic variant of eczema. Recombinant yeast allergens represent a useful tool to study molecular structures and differential sensitization patterns in the pathogenesis of AE.

Allergies and the skin, an interdisciplinary approach in GA2LEN and EAACI activities

Allergies and the skin, an interdisciplinary approach in GA²LEN and EAACI activities

No Effect of Anti-Interleukin-5 Therapy (Mepolizumab) on the Atopy Patch Test in Atopic Dermatitis Patients

Background: The atopy patch test (APT) is an in vivo model to study the induction of eczema by inhalant allergens in atopic dermatitis (AD) patients. Mepolizumab is a monoclonal antibody to interleukin-5, which reduces peripheral blood eosinophils. Previously, we reported that mepolizumab treatment did not result in clinical improvement in AD. The current study investigates the effect of mepolizumab therapy on the APT in the same patients. Methods: Mepolizumab treatment was given at days 0 and 7 in a double-blind placebo-controlled design. The APT was applied at days –2, 0, 14 and 28. Clinical evaluation of each APT was conducted 48 h after application at days 0, 2, 16 and 30. Skin biopsies were taken at days 0, 2 and 16 for eosinophil counts. Results: The mepolizumab-treated group showed no significant reduction in macroscopic outcome of the APT. Tissue eosinophils were reduced in the mepolizumab-treated group at day 16 compared with placebo; however, this was not significant. Conclusion: Mepolizumab therapy cannot prevent the eczematous reaction induced by the APT. Furthermore, the influx of tissue eosinophil numbers in the APT is not significantly inhibited after mepolizumab treatment compared with placebo, despite a significant reduction in peripheral blood eosinophils.

The diagnostic value of Atopy Patch Test and Skin Prick Test in children with atopic dermatitis and suspected food allergy

The diagnostic value of Atopy Patch Test and Skin Prick Test in children with atopic dermatitis and suspected food allergy

EAACI/GA2LEN Position paper: Present status of the atopy patch test*

A number of scientific reports have been published on patch tests with protein allergens performed on patients with atopic eczema (AE). Evaluation of eczematous skin lesions with an atopy patch test (APT) can be used as a diagnostic tool in characterizing patients with aeroallergen- and food-triggered AE. Indications for testing with APT, choice of allergens (aeroallergens and foods), test materials and technique, including present knowledge on sensitivity and specificity, are reviewed on the basis of available literature. This position paper also points out the need for future research on the clinical use of the APT.

The atopy patch test in the diagnostic workup of suspected food-related symptoms in children

There is an increasing need to develop test instruments that make oral food challenges superfluous. We sought to study the utility of atopy patch tests (APTs) in the diagnostic workup of food allergy. We investigated 437 children (median age, 13 months; 90% with atopic dermatitis) referred for evaluation of suspected food allergy. Specific serum IgE (sIgE) measurements, skin prick tests (SPTs), APTs, and controlled oral food challenges were performed. We analyzed 873 oral challenges with cow's milk, hen's egg, wheat, and/or soy. One thousand seven hundred single APTs were performed. As a single parameter, the APTs showed the best specificity compared with sIgE measurements, SPTs, or both. Combining the APT with either the SPT or sIgE measurement resulted in improved sensitivity and specificity. Decision points for sIgE measurement and for the SPT showed lower values when combined with a positive APT result. Correctly bypassing an oral food challenge with combined testing, including APTs, only between 0.5% and 7% (99% predicted probability) and between 6% and 14% (using 95% predicted probability) of children would fulfill the criteria for avoiding an oral food challenge. Although the predictive capacity of the APT is improved when combined with sIgE measurement or the SPT, oral food challenges become superfluous in only 0.5% to 14% of study patients. In addition, the APT is time consuming and demands a highly experienced test evaluator. For daily clinical practice, the APT adds only a small predictive value to the standard SPT and sIgE measurement in the diagnostic workup of suspected food-related symptoms in our study population.

Atopy patch test for the diagnosis of food protein‐induced enterocolitis syndrome

Food protein-induced enterocolitis syndrome (FPIES) is thought to be a non-IgE mediated food allergy syndrome. Affected infants typically demonstrate gastrointestinal symptoms after hours after ingestion of the offending food. Traditional allergy testing is not useful for this disorder because tests for food specific IgE are routinely negative. A diagnostic oral food challenge (OFC) is the only method to confirm the diagnosis of FPIES. This prospective study was undertaken to determine whether the atopy patch test (APT) is able to predict the results of the OFC. Nineteen infants with suspected FPIES by clinical history underwent APT to the suspected foods. After APT was performed, subjects underwent OFC to determine whether FPIES was present. The results of APT and OFC were compared and used to calculate sensitivity and specificity of the APT. APT predicted the results of oral food challenges in 28/33 instances. There were 16 cases of FPIES confirmed by oral food challenges. In all 16 cases of FPIES, the APT was positive to the suspected food. However, the APT was positive in five instances where the oral food challenge was negative. All 12 patients with a negative APT had a negative oral food challenge to the suspected food. APT appears to be a promising diagnostic tool for the diagnosis of FPIES.

Atopy patch testing in children with asthma and rhinitis symptoms allergic to house dust mite

The atopy patch test (APT) is generally used to assess immunoglobulin E (IgE) mediated sensitization to allergens in patients with atopic dermatitis, but its diagnostic role in children with respiratory allergy is still controversial. The aim of the study was to evaluate APT with house dust mite (HDM) in children with asthma and rhinitis symptoms allergic to HDM and its relevance to skin prick test (SPT) diameters and specific IgE levels. The study population consisted of 33 children, aged 8-16 yr (median: 12 yr) with asthma and 30 children with allergic rhinitis in the same age range (median: 11 yr). All patients had positive SPT results and high serum specific IgE levels for Dermatophagoides pteronyssinus APT was performed on back skin of all patients with 200 index of reactivity (IR)/ml of D. pteronyssinus allergen extracts in petrolatum (Stallerpatch) and evaluated at 72 h. Of 63 patients, 16 (25%) showed a positive patch test result. APT with HDM showed 30% (10/33) positivity among the patients with asthma and 20% (6/30) positivity among the patients with allergic rhinitis. APT presented no significant correlation with age, SPT diameter, serum total and specific IgE levels for D. pteronyssinus, nasal provocation test or pulmonary function test results. Patch testing with HDM may partly identify mite sensitive children with respiratory allergy. Positive APT results may imply that delayed hypersensitivity reactions play a role in children with asthma and rhinitis allergic to HDM.

Comment utiliser le Diallertest ® ?

Cow's milk allergy in children may involve several immunological mechanisms, IgE-mediated, responsible for immediate reactions, and non IgE-mediated, responsible for delayed or semi-delayed reactions. Clinical symptoms in children are largely dominated by atopic dermatitis and digestive manifestations, most of the time related to non IgE-mediated reactions, so that classical allergologic investigations, prick tests and measurement of serum specific IgE, are often negative. In these situations dominated by delayed or semi-delayed manifestations of milk allergy, atopy patch tests such as Diallertest ®, a ready-to-use one, may facilitate the diagnosis.

Diagnosis and treatment of atopic dermatitis in children and adults: European Academy of Allergology and Clinical Immunology/American Academy of Allergy, Asthma and Immunology/PRACTALL Consensus Report

There are remarkable differences in the diagnostic and therapeutic management of atopic dermatitis practiced by dermatologists and pediatricians in different countries. Therefore, the European Academy of Allergy and Clinical Immunology and the American Academy of Allergy, Asthma and Immunology nominated expert teams who were given the task of finding a consensus to serve as a guideline for clinical practice in Europe as well as in North America. The consensus report is part of the PRACTALL initiative, which is endorsed by both academies.

Modulation of Atopy Patch Test and Skin Prick Test by Pretreatment with 1% Pimecrolimus Cream

Background: In a subgroup of patients with atopic eczema (AE), aeroallergens are relevant eliciting factors. The atopy patch test (APT) was proposed as inflammation model for AE. Objective: It was the aim of this study to investigate the effect of pretreatment with 1% pimecrolimus cream (Elidel^®) on the APT and skin prick test (SPT). Methods: In a randomized, controlled, double-blind study, 20 patients with AE and positive SPT and APT screening reaction to house dust mite Dermatophagoides pteronyssinus, cat dander, grass or birch pollen were enrolled (age 20 ± 11 years, 55% males). For 2 weeks, patients twice daily applied pimecrolimus and vehicle control to marked fields on their backs and forearms. Then, APT was performed (200 index of reactivity/g extracts in petrolatum; Stallergènes, France) on both fields on the back and SPT was performed on the pretreated forearms. Results: Including only patients with different readings (n = 13), stronger APT suppression of at least 1 ETFAD (European Task Force on Atopic Dermatitis) grade in the pimecrolimus area versus intraindividual control was observed in 10 of these patients after 48 and 72 h (p < 0.05; 90% CI 50.5–93.4). Including all 20 subjects, the analysis still showed a borderline significance compared with the vehicle (p = 0.0564). SPT with histamine and aeroallergens showed a median 7.5–10% reduction in actively pretreated areas (p = 0.086). Immunohistochemical analysis in 2 patients revealed an induction of interferon-γ in primecrolimus-pretreated skin. Conclusion: APT can be used as a model for AE skin inflammation. It was shown for the first time that pimecrolimus pretreatment has a potential to suppress the development of lesions induced by aeroallergen exposure in patients with AE.