The reproducibility of the allergy skin test scoring and interpretation by board-certified/board-eligible allergists

The effect of applied force and device design on skin prick test performance

BACKGROUND

Skin prick tests (SPTs) are difficult to standardize, and SPT performance mainly relies on the clinician's expertise. So far, the effect of various factors such as device types, shape, variety of material type, and applied force on the performance of SPT has not been extensively investigated.

OBJECTIVE

To investigate the effect of various factors, including type or shape of devices, material type, and applied force, on the performance of SPT.

METHODS

Four SPT devices with different shapes and materials were applied on 12 subjects under 3 different applied forces (30, 45, and 60 g). The results were compared with standard method using an ALK lancet pricked by an experienced clinician.

RESULTS

A total of 480 pricks were conducted on 12 subjects. The wheal sizes and sensitivities of all devices increased with higher applied forces. The thinner lancets with a long sharp tip had relatively higher analytical sensitivities and provided 100% sensitivity at applied forces of 45 g and above. The pain scores of all devices at applied forces of 30 to 60 g ranged from 1.00 to 1.81 with minimal incidences of bleeding (0%-4.17%), whereas the pain score of the standard method by the ALK lancet was 2.08 with much higher incidences of bleeding at 27.08%.

CONCLUSION

The type/shape of the SPT device and applied force are the essential factors affecting the performance of SPT. The study result could pave the way toward higher performance and standardized SPT.

TRIAL REGISTRATION

The Thai Clinical Trials Registry identification number: TCTR20220627004 (https://www.thaiclinicaltrials.org/show/TCTR20220627004).

High Histamine Control Concentration Leads to False Negative Allergy Skin Testing

BACKGROUND

Allergy skin test reliability depends on the reagents and controls selected. Histamine is used at 1 mg/ml and 6 mg/ml concentration but few studies address the rationale for selecting one versus the other and how this may impact diagnostic accuracy.

OBJECTIVE

To determine the rate of false negative allergen skin tests responses between UniTest PC (using the 1 mg/mL histamine) and Quintip devices (using 6 mg/mL) for 4 common aeroallergens.

METHODS

Subjects aged 18-65 with symptoms of allergy to cat and/or ragweed received skin testing with 4 aeroallergens (dust mite mix, timothy grass, ragweed, cat), histamine and control diluent. Those individuals who tested positive to cat or ragweed with one skin prick test (SPT) device but not the other then proceeded to nasal allergen challenge (NAC). The primary outcomes were the aeroallergen false negative rates and sensitivities of the skin test devices followed by nasal allergen (NAC).

RESULTS

Twenty-five individuals were recruited and underwent a total of 300 SPTs. SPT to allergens (ragweed, dust mite, cat, and timothy grass) resulted in a statistically significant difference in wheal size among the two skin testing devices (p value <0.0001, 0.0001, 0.0006, and 0.0053 respectively). Six NAC procedures were performed to cat/ragweed and 5 of 6 (83% were positive). The overall allergen sensitivity rate for UniTest and Quintip were 97% and 78% respectively with most false negatives due to the use of 6 mg/ml histamine control reagent.

CONCLUSION

Our study shows that 6 mg/ml concentration of histamine control reagent may contribute to a false interpretation of aeroallergen skin prick test results.

Serum level and clinical significance of vitamin E in children with allergic rhinitis

BACKGROUND

Allergic rhinitis (AR) is one of the most prevalent allergic diseases in children. This study aimed to investigate the association between serum concentrations of vitamin E and AR to determine if the vitamin E level is correlated with the occurrence and severity of AR.

METHODS

A total of 113 children were enrolled in this cross-sectional study. Sixty-five children in the outpatient group were diagnosed with AR, and 48 healthy children were recruited as controls. All subjects underwent serum vitamin E (adjusted for total cholesterol and triglycerides) measurements. Serum to total IgE (tIgE), the five most common allergen-specific IgE (sIgE) levels and skin prick test (SPT) were measured in children with AR. The severity of AR was assessed with the nasal symptoms score, and the situation of exposure to passive smoking were inquired.

RESULTS

Serum vitamin E levels were significantly lower in the AR group than in the normal children (P < 0.001). A significant negative correlation was observed between serum vitamin E levels and sIgE as well as the SPT grade. Serum vitamin E levels were also inversely related to the nasal symptoms score; however, statistical significance was not found.

CONCLUSIONS

A significantly lower vitamin E level was found in children with AR. Lower serum vitamin E levels may have correlation with the occurrence of AR in children. However, serum vitamin E levels were not statistically correlated with the severity of AR.

Advances in IgE Testing for Diagnosis of Allergic Disease

Since its discovery in 1967, IgE antibody detection in skin and blood has identified a state of allergic sensitization and served as a necessary but not sufficient risk factor that requires objective symptoms to make the definitive diagnosis of human allergic disease. More recently, quantitative IgE antibody levels in serum against allergenic extracts, molecules, and epitopes have pushed its application into more accurately identifying the specificity of the allergic response for targeting immunotherapy, predicting allergic symptom severity after allergen exposure, and attempting to distinguish tolerance from food allergy. This review examines new in vivo and in vitro developments in the design, performance, interference, and application of the methods used to identify allergic sensitization. The increasing accepted applications of molecular allergen and allergen epitope-based IgE antibody measurements, especially as applied to food allergy diagnosis and management, are highlighted as state-of-the-art advances. Despite these major advances in allergic sensitization documentation, their ultimate value requires integration by the clinician with the patient's history and pretest probability of disease.

IgE allergy diagnostics and other relevant tests in allergy, a World Allergy Organization position paper

Currently, testing for immunoglobulin E (IgE) sensitization is the cornerstone of diagnostic evaluation in suspected allergic conditions. This review provides a thorough and updated critical appraisal of the most frequently used diagnostic tests, both in vivo and in vitro. It discusses skin tests, challenges, and serological and cellular in vitro tests, and provides an overview of indications, advantages and disadvantages of each in conditions such as respiratory, food, venom, drug, and occupational allergy. Skin prick testing remains the first line approach in most instances; the added value of serum specific IgE to whole allergen extracts or components, as well as the role of basophil activation tests, is evaluated. Unproven, non-validated, diagnostic tests are also discussed. Throughout the review, the reader must bear in mind the relevance of differentiating between sensitization and allergy; the latter entails not only allergic sensitization, but also clinically relevant symptoms triggered by the culprit allergen.

Novel Bead-Based Epitope Assay is a sensitive and reliable tool for profiling epitope-specific antibody repertoire in food allergy

Identification of allergenic IgE epitopes is instrumental for the development of novel diagnostic and prognostic methods in food allergy. In this work, we present the quantification and validation of a Bead-Based Epitope Assay (BBEA) that through multiplexing of epitopes and multiple sample processing enables completion of large experiments in a short period of time, using minimal quantities of patients’ blood. Peptides that are uniquely coupled to beads are incubated with serum or plasma samples, and after a secondary fluorophore-labeled antibody is added, the level of fluorescence is quantified with a Luminex reader. The signal is then normalized and converted to epitope-specific antibody binding values. We show that the effect of technical artifacts, i.e. well position or reading order, is minimal; and batch effects - different individual microplate runs - can be easily estimated and eliminated from the data. Epitope-specific antibody binding quantified with BBEA is highly reliable, reproducible and has greater sensitivity of epitope detection compared to peptide microarrays. IgE directed at allergenic epitopes is a sensitive biomarker of food allergy and can be used to predict allergy severity and phenotypes; and quantification of the relationship between epitope-specific IgE and IgG4 can further improve our understanding of the immune mechanisms behind allergic sensitization.

Robust automated reading of the skin prick test via 3D imaging and parametric surface fitting

The conventional reading of the skin prick test (SPT) for diagnosing allergies is prone to inter- and intra-observer variations. Drawing the contours of the skin wheals from the SPT and scanning them for computer processing is cumbersome. However, 3D scanning technology promises the best results in terms of accuracy, fast acquisition, and processing. In this work, we present a wide-field 3D imaging system for the 3D reconstruction of the SPT, and we propose an automated method for the measurement of the skin wheals. The automated measurement is based on pyramidal decomposition and parametric 3D surface fitting for estimating the sizes of the wheals directly. We proposed two parametric models for the diameter estimation. Model 1 is based on an inverted Elliptical Paraboloid function, and model 2 on a super-Gaussian function. The accuracy of the 3D imaging system was evaluated with validation objects obtaining transversal and depth accuracies within ± 0.1 mm and ± 0.01 mm, respectively. We tested the method on 80 SPTs conducted in volunteer subjects, which resulted in 61 detected wheals. We analyzed the accuracy of the models against manual reference measurements from a physician and obtained that the parametric model 2 on average yields diameters closer to the reference measurements (model 1: -0.398 mm vs. model 2: -0.339 mm) with narrower 95% limits of agreement (model 1: [-1.58, 0.78] mm vs. model 2: [-1.39, 0.71] mm) in a Bland-Altman analysis. In one subject, we tested the reproducibility of the method by registering the forearm under five different poses obtaining a maximum coefficient of variation of 5.24% in the estimated wheal diameters. The proposed method delivers accurate and reproducible measurements of the SPT.

Reliability of allergy skin testing

BACKGROUND

Percutaneous allergen skin testing remains an established benchmark for diagnosing atopic disease. The reliability of skin testing depends greatly on the performance of allergen extracts used, methods used, and the presence of antihistamine medications.

OBJECTIVE

To determine the differential effect of cetirizine on 2 different concentrations of histamine control solution and 5 common allergens used for percutaneous skin testing.

METHODS

Twelve individuals underwent skin testing with histamine (1 and 6 mg/mL), control diluent, and 5 common aeroallergens. Wheal and flare measurements were measured in a masked fashion by a single operator. Cetirizine was administered for 4 consecutive days to determine the effect on both histamine and allergen wheal and flare responses.

RESULTS

A total of 384 skin tests were performed on 12 volunteers. Cetirizine began to suppress wheal and flare responses at 1 hour (P < .05), with maximum suppression at day 5 (P < .05). Wheal and flare responses returned to greater than 90% baseline within 4 days of not taking cetirizine. Suppression was more apparent with 1 vs 6 mg/mL of histamine (62% vs 33%). Four of the 12 individuals taking cetirizine had a positive skin test result using 6 mg/mL of histamine control when the 1-mg/mL histamine test result was negative. Importantly, twice as many individuals had false-negative allergen responses using 6 mg/mL of histamine vs the 1 mg/mL as a positive control, although this finding did not reach statistical significance.

CONCLUSION

The use of a 6-mg/mL histamine control for some percutaneous skin test devices may result in more false-negative allergen responses because of the inability to detect the presence of antihistamines.

International Consensus Statement on Allergy and Rhinology: Allergic Rhinitis

BACKGROUND

Critical examination of the quality and validity of available allergic rhinitis (AR) literature is necessary to improve understanding and to appropriately translate this knowledge to clinical care of the AR patient. To evaluate the existing AR literature, international multidisciplinary experts with an interest in AR have produced the International Consensus statement on Allergy and Rhinology: Allergic Rhinitis (ICAR:AR).

METHODS

Using previously described methodology, specific topics were developed relating to AR. Each topic was assigned a literature review, evidence-based review (EBR), or evidence-based review with recommendations (EBRR) format as dictated by available evidence and purpose within the ICAR:AR document. Following iterative reviews of each topic, the ICAR:AR document was synthesized and reviewed by all authors for consensus.

RESULTS

The ICAR:AR document addresses over 100 individual topics related to AR, including diagnosis, pathophysiology, epidemiology, disease burden, risk factors for the development of AR, allergy testing modalities, treatment, and other conditions/comorbidities associated with AR.

CONCLUSION

This critical review of the AR literature has identified several strengths; providers can be confident that treatment decisions are supported by rigorous studies. However, there are also substantial gaps in the AR literature. These knowledge gaps should be viewed as opportunities for improvement, as often the things that we teach and the medicine that we practice are not based on the best quality evidence. This document aims to highlight the strengths and weaknesses of the AR literature to identify areas for future AR research and improved understanding.

Effects of allergen sensitization on response to therapy in children with eosinophilic esophagitis

BACKGROUND

In children with eosinophilic esophagitis (EoE) foods are the most common disease triggers, but environmental allergens are also suspected culprits.

OBJECTIVE

To determine the effects of environmental allergen sensitization on response to treatment in children with EoE in the southeastern United States.

METHODS

Patients 2 to 18 years old who were referred to the Arkansas Children's Hospital Eosinophilic Gastrointestinal Disorders Clinic from January 2012 to January 2016 were enrolled in a prospective, longitudinal cohort study with collection of demographics, clinical symptoms, medical history, allergy sensitization profiles, and response to treatment over time. Comparisons were made between complete responders (peak esophageal eosinophil count <15 per high-power field [HPF]) and nonresponders (>25 eosinophils per HPF) after treatment with diet elimination alone, swallowed corticosteroids alone, or diet elimination and swallowed corticosteroids. Sensitization patterns to environmental allergens found in the southeastern United States were analyzed for the effect on treatment response.

RESULTS

A total of 223 individuals were enrolled. Of these, 182 had environmental allergy profiling and at least one endoscopy while receiving proton pump inhibitor (PPI) therapy. Twenty-nine individuals had PPI-responsive EoE and were excluded from further analysis, leaving 123 individuals with non-PPI-responsive EoE who were further analyzed; 72 (58.5%) were complete responders and 33 (26.8%) were nonresponders. Seventeen individuals (13.8%) were partial responders (≥1 but ≤25 eosinophils per HPF) and excluded from further analysis. Nonresponders were more likely to be sensitized to perennial allergens (P = .02). There was no significant difference in response based on seasonal allergen sensitization. Individuals with mold or cockroach sensitization were more likely to fail combination diet and swallowed corticosteroid treatment (P = .02 and P = .002).

CONCLUSION

Perennial allergen and mold sensitization may lead to nonresponse to EoE treatment in some patients. Additional studies are needed to further understand the effect of environmental allergens on EoE.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT01779154.

Prick test: evolution towards automated reading

The prick test is one of the most common medical methods for diagnosing allergies, and it has been carried out in a similar and laborious manner over many decades. In an attempt to standardize the reading of the test, many researchers have tried to automate the process of measuring the allergic reactions found by developing systems and algorithms based on multiple technologies. This work reviews the techniques for automatic wheal measurement with the aim of pointing out their advantages and disadvantages and the progress in the field. Furthermore, it provides a classification scheme for the different technologies applied. The works discussed herein provide evidence that significant challenges still exist for the development of an automatic wheal measurement system that not only helps allergists in their medical practice but also allows for the standardization of the reading and data exchange. As such, the aim of the work was to serve as guideline for the development of a proper and feasible system.

Clinical practice guideline: Allergic rhinitis

OBJECTIVE

Allergic rhinitis (AR) is one of the most common diseases affecting adults. It is the most common chronic disease in children in the United States today and the fifth most common chronic disease in the United States overall. AR is estimated to affect nearly 1 in every 6 Americans and generates $2 to $5 billion in direct health expenditures annually. It can impair quality of life and, through loss of work and school attendance, is responsible for as much as $2 to $4 billion in lost productivity annually. Not surprisingly, myriad diagnostic tests and treatments are used in managing this disorder, yet there is considerable variation in their use. This clinical practice guideline was undertaken to optimize the care of patients with AR by addressing quality improvement opportunities through an evaluation of the available evidence and an assessment of the harm-benefit balance of various diagnostic and management options.

PURPOSE

The primary purpose of this guideline is to address quality improvement opportunities for all clinicians, in any setting, who are likely to manage patients with AR as well as to optimize patient care, promote effective diagnosis and therapy, and reduce harmful or unnecessary variations in care. The guideline is intended to be applicable for both pediatric and adult patients with AR. Children under the age of 2 years were excluded from the clinical practice guideline because rhinitis in this population may be different than in older patients and is not informed by the same evidence base. The guideline is intended to focus on a limited number of quality improvement opportunities deemed most important by the working group and is not intended to be a comprehensive reference for diagnosing and managing AR. The recommendations outlined in the guideline are not intended to represent the standard of care for patient management, nor are the recommendations intended to limit treatment or care provided to individual patients.

ACTION STATEMENTS

The development group made a strong recommendation that clinicians recommend intranasal steroids for patients with a clinical diagnosis of AR whose symptoms affect their quality of life. The development group also made a strong recommendation that clinicians recommend oral second-generation/less sedating antihistamines for patients with AR and primary complaints of sneezing and itching. The panel made the following recommendations: (1) Clinicians should make the clinical diagnosis of AR when patients present with a history and physical examination consistent with an allergic cause and 1 or more of the following symptoms: nasal congestion, runny nose, itchy nose, or sneezing. Findings of AR consistent with an allergic cause include, but are not limited to, clear rhinorrhea, nasal congestion, pale discoloration of the nasal mucosa, and red and watery eyes. (2) Clinicians should perform and interpret, or refer to a clinician who can perform and interpret, specific IgE (skin or blood) allergy testing for patients with a clinical diagnosis of AR who do not respond to empiric treatment, or when the diagnosis is uncertain, or when knowledge of the specific causative allergen is needed to target therapy. (3) Clinicians should assess patients with a clinical diagnosis of AR for, and document in the medical record, the presence of associated conditions such as asthma, atopic dermatitis, sleep-disordered breathing, conjunctivitis, rhinosinusitis, and otitis media. (4) Clinicians should offer, or refer to a clinician who can offer, immunotherapy (sublingual or subcutaneous) for patients with AR who have inadequate response to symptoms with pharmacologic therapy with or without environmental controls. The panel recommended against (1) clinicians routinely performing sinonasal imaging in patients presenting with symptoms consistent with a diagnosis of AR and (2) clinicians offering oral leukotriene receptor antagonists as primary therapy for patients with AR. The panel group made the following options: (1) Clinicians may advise avoidance of known allergens or may advise environmental controls (ie, removal of pets; the use of air filtration systems, bed covers, and acaricides [chemical agents formulated to kill dust mites]) in patients with AR who have identified allergens that correlate with clinical symptoms. (2) Clinicians may offer intranasal antihistamines for patients with seasonal, perennial, or episodic AR. (3) Clinicians may offer combination pharmacologic therapy in patients with AR who have inadequate response to pharmacologic monotherapy. (4) Clinicians may offer, or refer to a surgeon who can offer, inferior turbinate reduction in patients with AR with nasal airway obstruction and enlarged inferior turbinates who have failed medical management. (5) Clinicians may offer acupuncture, or refer to a clinician who can offer acupuncture, for patients with AR who are interested in nonpharmacologic therapy. The development group provided no recommendation regarding the use of herbal therapy for patients with AR.

Skin prick/puncture testing in North America: a call for standards and consistency

BACKGROUND

Skin prick/puncture testing (SPT) is widely accepted as a safe, dependable, convenient, and cost-effective procedure to detect allergen-specific IgE sensitivity. It is, however, prone to influence by a variety of factors that may significantly alter test outcomes, affect the accuracy of diagnosis, and the effectiveness of subsequent immunotherapy regimens. Proficiency in SPT administration is a key variable that can be routinely measured and documented to improve the predictive value of allergy skin testing.

METHODS

Literature surveys were conducted to determine the adherence to repeated calls for development and implementation of proficiency testing standards in the 1990's, the mid-2000's and the 2008 allergy diagnostics practice parameters.

RESULTS

Authors publishing clinical research in peer-reviewed journals and conducting workshops at annual scientific meetings have recommended proficiency testing based primarily on its potential to reduce variability, minimize confounding test results, and promote more effective immunotherapeutic treatments. Very few publications of clinical studies, however, appear to report proficiency testing data for SPT performance. Allergen immunotherapy recommendations are updated periodically by the Joint Task Force on Practice Parameters representing the American Academy of Allergy, Asthma and Immunology (AAAAI), the American College of Allergy, Asthma and Immunology (ACAAI), and the Joint Council of Allergy, Asthma and Immunology (JCAAI).

CONCLUSIONS

Despite consensus that all staff who perform SPT should meet basic quality assurance standards that demonstrate their SPT proficiency, the gap between recommendations and daily practice persists. By embracing standards, the accuracy of SPT and allergy diagnosis can be optimized, ultimately benefiting patients with allergic disease.

Associations between pollen counts, pollutants, and asthma-related hospital admissions in a high-density Indian metropolis

BACKGROUND

The seasonal pattern of asthma-related hospitalization has often been correlated with ambient allergen/pollutant levels.

OBJECTIVE

To examine the relationship between asthma-related hospital admissions (ARHA) and outdoor pollen, spore, and pollutant levels for adult patients in a densely populated Indian megacity Kolkata.

METHODS

ARHA data were obtained from two major teaching hospitals of the city. Pollen and spores causing allergic sensitization were identified by skin prick tests (SPTs) among respiratory allergic subjects (N = 1353). Outdoor concentrations of aeroallergens were determined using a Burkard sampler for five consecutive years (2004-2009). Levels of NO(2), SO(2), suspended particulate matters (SPMs), and respirable particulate matters (RPMs) were made available by West Bengal Pollution Control Board (WBPCB, Government of West Bengal). Poisson multivariate Poisson regression (with adjustments for overdispersion) was used to model the data. Results. We found that ARHA in Kolkata increased with predictable regularity in March and September, while remaining low in January and July. SPT showed highly positive skin reactions with grass/weed and palm pollens in respiratory allergic patients, while Aspergilli spores also evoked good sensitivity. In our regression model, the airborne pollen types, Cheno-Amaranthaceae and Cyperaceae, and the inorganic pollutant, SO(2) and RPM, were significantly associated with ARHA (p < .05).

CONCLUSION

ARHA in the megacity of Kolkata shows two seasonal peaks that can be correlated with outdoor grass/weed pollen and RPM concentrations. In contrast, the city's ambient fungal spore counts were not found to be significantly associated.

Asthma outcomes: biomarkers

BACKGROUND

Measurement of biomarkers has been incorporated within clinical research studies of asthma to characterize the population and associate the disease with environmental and therapeutic effects.

OBJECTIVE

National Institutes of Health institutes and federal agencies convened an expert group to propose which biomarkers should be assessed as standardized asthma outcomes in future clinical research studies.

METHODS

We conducted a comprehensive search of the literature to identify studies that developed and/or tested asthma biomarkers. We identified biomarkers relevant to the underlying disease process progression and response to treatment. We classified the biomarkers as either core (required in future studies), supplemental (used according to study aims and standardized), or emerging (requiring validation and standardization). This work was discussed at an National Institutes of Health-organized workshop convened in March 2010 and finalized in September 2011.

RESULTS

Ten measures were identified; only 1, multiallergen screening to define atopy, is recommended as a core asthma outcome. Complete blood counts to measure total eosinophils, fractional exhaled nitric oxide (Feno), sputum eosinophils, urinary leukotrienes, and total and allergen-specific IgE are recommended as supplemental measures. Measurement of sputum polymorphonuclear leukocytes and other analytes, cortisol measures, airway imaging, breath markers, and system-wide studies (eg, genomics, proteomics) are considered as emerging outcome measures.

CONCLUSION

The working group participants propose the use of multiallergen screening in all asthma clinical trials to characterize study populations with respect to atopic status. Blood, sputum, and urine specimens should be stored in biobanks, and standard procedures should be developed to harmonize sample collection for clinical trial biorepositories.

Comparison of subjective and objective intradermal allergy test scoring methods in dogs with atopic dermatitis

An intradermal allergy test (IDT) is an important diagnostic tool for identifying offending allergens in canine atopic dermatitis. No standardized method of scoring an IDT has been described. The purpose of this study was to determine whether there is a correlation between a conventional, subjective IDT scoring method based on perceived wheal diameter, erythema, and turgor (0-4+) and an objective scoring method based on measuring wheal diameter alone. Thirty-four atopic dogs were skin tested with 68 different allergens. All skin tests were performed according to standard procedures, and any IDT score ≥2+ was considered clinically significant. When the subjective IDT scores were compared with the objective IDT scores in all dogs, there was a moderate level of correlation overall (r=0.457; P <0.0001). The highest level of agreement between subjective and objective scores was noted with the reactions assigned subjective scores of "0" and "2+." Overall, there was a slight level of agreement between subjective and objective scores based on clinical significance (i.e., subjective scores ≥2+; κ=0.20; P <0.0001). In conclusion, the authors believe that the objective scoring method used in this study may provide a point of reference for inexperienced individuals (dermatology residents, veterinarians, technicians) when learning to grade an IDT.

Intradermal skin test results correlate with atopy

Intradermal skin testing (IDST) is performed by most allergists, but its value remains controversial. In most previous studies assessing the value of IDST, a positive result was based on a 5- to 6-mm wheal and erythema. While a subject's immediate reaction upon allergen exposure is a common endpoint to determine "allergy," additional known allergic phenomena such as the delayed or late-phase response to allergen exposure suggest that correlation only with current history or acute challenge may result in an incorrect labeling of false-positive results when, in fact, there is a physiologic response to exposure, albeit a reaction not immediately evident. We conducted a retrospective study to determine if positive IDST reactions represent nonspecific irritation or if they correlate with atopy. We retrospectively reviewed the records of 100 patients who had undergone skin prick testing (SPT) and IDST and compiled data on their age, sex, diagnosis, and number of skin and intradermal reactions. Results were analyzed according to a general linear model to see if the development of a positive IDST result correlated with atopy (defined as SPT positivity). We found statistically significant differences between SPT-positive and -negative patients with regard to diagnoses of asthma, rhinitis, or both (p=0.008). Controlling for asthma and rhinitis, we also found a significant association between atopy and a positive IDST result; among atopic (SPT+) patients, a mean of 25.9% of IDST results were positive, compared with a rate of only 6.7% IDST positivity among the nonatopic (SPT-) patients (p<0.0001). We conclude that IDST is more commonly positive in atopic (SPT+) than nonatopic (SPT-) patients, suggesting that a positive IDST represents genuine atopy and bona fide sensitization rather than nonspecific irritation.

Allergy skin testing: what nurses need to know

Skin testing is a common procedure in any clinical setting. Critical care nurses will encounter skin testing in the inpatient and outpatient settings primarily to test for patient allergies to environmental factors, or allergies to certain medications. As there is a great deal of controversy about standard practices surrounding the different tests, information about various allergy tests and testing protocols is vital. Quality assurance standards should be met to ensure adequacy of the skin testing technique. Persons performing skin tests should undergo evaluation of their technique. To improve the predictive values of skin testing, and to ameliorate the incidence or severity of adverse affects, it is important for the critical care nurse to understand the dynamics of the test and the possible risks, along with variables that can confound the results. By doing this, nurses will improve not only patient outcomes related to the testing itself but also the value and reliability of the most effective diagnostic tool available for allergic disease.

Clinical laboratory assessment of immediate-type hypersensitivity

Clinical laboratory analyses aid in the diagnosis and management of human allergic (IgE-dependent) diseases. Diagnosis of immediate-type hypersensitivity begins with a thorough clinical history and physical examination. Once symptoms compatible with an allergic disorder have been identified, a skin test, blood test, or both for allergen-specific IgE antibodies provide confirmation of sensitization, which strengthens the diagnosis. Skin testing provides a biologically relevant immediate-type hypersensitivity response with resultant wheal-and-flare reactions within 15 minutes of allergen application. Allergen-specific IgE antibody in serum is quantified by using 3 laboratory-based autoanalyzers (ImmunoCAP, Immulite, and HYTEC-288) and novel microarray and lateral-flow immunoassays. Technologic advances in serologic allergen-specific IgE measurements have involved increased automation, with enhanced reproducibility, greater quantification, lower analytic sensitivity, and component-supplemented extract-based allergen use. In vivo provocation tests involving inhalation, ingestion, or injection of allergens serve to clarify discordant history and skin- or blood-based measures of sensitization. Other diagnostic allergy laboratory analyses include total and free serum IgE measurement, precipitating IgG antibodies specific for organic dusts, mast cell tryptase, and indicator allergen analyses to assess indoor environments to promote patient-targeted allergen avoidance programs. A critique is provided on the predictive utility of serologic measures of specific IgE for food allergy and asthma. Reasons for the lack of clinical utility for food-specific IgG/IgG4 measurements in allergy diagnosis are examined. When the specific IgE measures are inconsistent with the clinical history, they should be confirmed by means of repeat and alternative method analysis. Ultimately, the patient's clinical history remains the principal arbiter that determines the final diagnosis of allergic disease.

Diagnostic evaluation of food-related allergic diseases

Food allergy is a serious and potentially life-threatening problem for an estimated 6% of children and 3.7% of adults. This review examines the diagnostic process that begins with a patient's history and physical examination. If the suspicion of IgE-mediated food allergy is compelling based on the history, skin and serology tests are routinely performed to provide confirmation for the presence of food-specific IgE antibody. In selected cases, a provocation challenge may be required as a definitive or gold standard reference test for confirmation of IgE mediated reactions to food. Variables that influence the accuracy of each of the diagnostic algorithm phases are discussed. The clinical significance of food allergen-specific IgE antibody cross-reactivity and IgE antibody epitope mapping of food allergens is overviewed. The advantages and limitations of the various diagnostic procedures are examined with an emphasis on future trends in technology and reagents.

General anesthetic allergy testing

Anaphylaxis in the setting of general anesthesia is a rare but potentially lethal event. The investigation of severe reactions is important for confirming the clinical diagnosis and identifying likely causative agents and safe agents that may be used in the future. Many comprehensive reports have described the testing protocol of individual specialized units, whereas there has been no standardization of testing techniques or formal assessment of these tests' diagnostic accuracy. We review the literature with reference to the recently published standards for reporting of diagnostic accuracy (STARD) and make recommendations for future studies of diagnostic accuracy in the field.

Skin prick tests and allergy diagnosis

Skin testing remains an essential diagnostic tool in modern allergy practice. A significant variability has been reported regarding technical procedures, interpretation of results and documentation. This review has the aim of consolidating methodological recommendations through a critical analysis on past and recent data. This will allow a better understanding on skin prick test (SPT) history; technique; (contra-) indications; interpretation of results; diagnostic pitfalls; adverse reactions; and variability factors.

The role of intradermal skin testing in inhalant allergy

OBJECTIVE

To provide an overview of the role of intradermal skin testing (IDST) in inhalant allergy.

DATA SOURCES

A literature search was conducted in MEDLINE to identify peer-reviewed articles related to IDST using the following keywords: skin testing, intradermal, intracutaneous, aeroallergen, and inhalant allergen. In addition, references cited within these articles were also reviewed.

STUDY SELECTION

Articles were selected based on their relevance to the topic.

RESULTS

The use of IDST for inhalant allergy varies widely among allergists. When performed, it is necessary to use a 100- to 1,000-fold dilution from the stock allergen extract. IDST is used routinely in the standardization of extracts in the United States. With a negative skin prick test result, a positive IDST result has low agreement with in vitro and challenge results and generally adds little to the diagnostic evaluation. In contrast, a negative IDST result generally has a high negative predictive value. Only a few inhalant allergens have been evaluated with challenge models for IDST. A summary of the data is also presented in tabular form.

CONCLUSIONS

Most of the literature suggests that with a negative skin prick test result, a positive IDST result adds little to the diagnostic evaluation of inhalant allergy. However, additional studies are necessary using challenge models for less potent and nonstandardized inhalant allergens (molds, trees, dog, weeds).

Diagnostic tests for human allergic disease

BACKGROUND

The diagnosis of human allergic disease begins with a thorough clinical history and physical examination. Once a temporal relationship has been identified between a patient's history of allergic symptoms and a defined allergen exposure, confirmatory analyses for IgE antibody involving skin or blood testing are performed to verify sensitization. Debate continues over the relative diagnostic utility of the in vivo and in vitro measures of IgE antibody.

OBJECTIVE

This overview examines the strengths and limitations of primary diagnostic confirmatory methods for in vivo detection (skin test, provocation test) and in vitro quantification of IgE antibody.

METHODS

A literature review was performed to examine diagnostic performance characteristics and variables that influence the accuracy of IgE antibody assays.

DISCUSSION

The clinical history and both in vivo and in vitro measures of IgE antibody are subject to variability and potential patient, clinician and technician-related bias. As such, in the absence of an absolute clinical history-based gold standard for defining the presence of allergic disease, the relative diagnostic performance (sensitivity, specificity) of in vivo versus in vitro assays of IgE antibody cannot be effectively determined. The review examines which allergic disease states and allergen specificities allow both groups of IgE antibody assays to produce comparable qualitative data for assessing the state of allergic sensitization. Skin testing has experienced few recent technological innovations, whereas an explosion has occurred in the improved performance (analytical sensitivity and specificity) of in vitro assays and enhanced quality of reagents for IgE antibody quantification. This review discusses the impact of point of care-testing assays, microarrays, the use of native and recombinant allergen molecules, automation, and disease prediction algorithms and the 2008 Clinical and Laboratory Standards Institute Guideline on IgE antibody methods, on the diagnosis of human allergic disease.

Variability of venom skin tests

PURPOSE OF REVIEW

Venom skin tests constitute the cornerstone in establishing the diagnosis of venom allergy. In spite of their fundamental role, data regarding their reproducibility and variability are rather sparse. This paper is an overview of our current knowledge on the extent of variability in venom skin testing, the possible causes for this phenomenon and its clinical implications. It points out certain clinical situations in which this possible variability should be taken into account and anticipates potential venues of expanding our understanding of this debatable subject.

RECENT FINDINGS

A single recent study addressed the reproducibility of skin tests and serum venom-specific immunoglobulin E levels. Using a simple positive-negative or vice versa criterion for all three venoms examined on two different sessions, this study showed an overall 66% reproducibility of the skin test reactions and 59% reproducibility of the venom-specific immunoglobulin E assay results. According to an accompanying editorial, however, the validity of these results needs to be confirmed.

SUMMARY

Determination of the real magnitude of venom skin test variability is required. At present, in specific clinical situations, repeated skin tests and measurement of serum venom-specific immunoglobulin E should be considered before the initiation of venom immunotherapy.

An analysis of the incidence of adenoid hypertrophy in allergic children

INTRODUCTION

The adenoidectomy is the most often made operation in small children but the reasons of adenoid hypertrophy are not completely explained. Some researches show that in part of children, allergy can be a risk factor for adenoid hypertrophy. The main aim of this study was the analysis of adenoid hypertrophy in children with different allergic diseases.

MATERIAL AND METHODS

Two separate groups of children were examined. The study group consisted of 436 children between 4 and 9 years old with allergic rhinitis and/or bronchial asthma and/or atopic dermatitis hypersensitive to house dust mites (interview, positive skin-prick test results). The control group consisted of 229 non-atopic children (negative interview and skin-prick tests) in the similar age. In the both groups we examined the incidence of adenoid hypertrophy and its dependence of the kind of allergic disease, age, sex, infections, results of skin-prick test and other sensitization.

RESULTS

The probability of adenoid hypertrophy was statistically more significant (logistic regression analysis) only in children from the study group with allergic rhinitis. There were no differences in adenoid hypertrophy incidence between children with other allergic diseases and the control group. The children from the study group with adenoid hypertrophy were more often hypersensitive to pollen and moulds allergens than the children without adenoid hypertrophy (chi square test). But there were no differences in the incidence of infection, age, sex and results of skin-prick tests.

CONCLUSION

The result of our study suggests that the chance of adenoid hypertrophy in allergic children hypersensitive to dust mites is greater only in them with allergic rhinitis.

Evidence-based allergy diagnostic tests

Effective management of allergic diseases relies on the ability to make an accurate diagnosis. Although clinicians rely on experience obtained over many years of practice, such experience is anecdotal and unique to the individual using it. The result is a tendency for patients with similar clinical presentations to receive different diagnoses and treatment, depending on which provider they happened to see. The probability that a patient has a particular diagnosis can be determined using a combination of diagnostic tests. To make the best use of tests, it is important to understand their performance characteristics in terms of reproducibility and likelihood ratios. A test that is reproducible but that does not predict the presence of a disease is not helpful, nor is an accurate test that is not reproducible. To improve the reproducibility of diagnostic tests, it is important that proficiency testing be instituted for both skin and in vitro tests so that the coefficient of variance can be determined. This has already been done for the latter and needs to be done for skin tests as well. With use of a combination of history and appropriate diagnostic tests, the probability that a particular diagnosis is present can be increased or decreased sufficiently either to confirm it or to rule it out. As proficiency testing of allergy tests becomes more common and the use of tests becomes more consistent, we believe that patients with allergic diseases will benefit.

Use of intradermal dilutional testing and skin prick testing: clinical relevance and cost efficiency

OBJECTIVES/HYPOTHESIS

The objective was to determine the agreement of the positive results from a multiple skin prick test (SPT) device with the ability to determine a definable endpoint through intradermal dilutional testing (IDT) to compare semiquantitatively the degree of positivity of SPT results with quantitative results from IDT and to analyze the cost of immunotherapy based on SPT compared with IDT guided by SPT.

STUDY DESIGN

Retrospective review of clinical data (random accrual).

METHODS

One hundred thirty-four patients underwent allergy screening using a multiple SPT device. Antigens testing positive by skin prick device were tested using IDT on a separate day. Antigens testing negative by SPT were not evaluated by IDT. Regional allergy testing practice patterns were determined, and a cost analysis using Medicare rates was performed

RESULTS

There was good agreement between an antigen testing positive by SPT and the determination of a definable endpoint (93.33%, n = 1,334 antigens). The degree of positivity from the SPT correlated poorly with the final endpoint concentration (r = 0.40, P < .0001). Blended testing techniques were similar in cost when compared with several commonly used allergy testing protocols.

CONCLUSIONS

Antigens which show reactivity to a multiple SPT device usually have a treatable endpoint that is independent of the degree of positivity of the SPT result. IDT is an important step in the determination of the strongest starting dose of immunotherapy that may be safely administered. Initiating immunotherapy in this manner may potentially create significant health care savings by shortening the time required for a patient to reach their individual maximally tolerated dose. The use of a relatively large screening panel is cost effective and does not increase the average number of antigens treated by immunotherapy. Blended allergy testing techniques that include IDT in their protocol are comparable in cost with commonly used allergy testing protocols.

Skin testing

OBJECTIVE

To provide the reader with a relevant review of the literature regarding skin testing in the allergist's office.

DATA SOURCES

A PubMed search for the years 1970 through 2005 was performed using the following keywords: allergy skin testing, skin prick testing, and intradermal skin testing.

STUDY SELECTION

Articles that highlighted aspects of sentinel to clinical allergists' use of skin testing in the office, such as methods of skin testing, intradermal vs skin prick testing, skin test devices, and methods of expressing skin test results, were selected for further review.

RESULTS

Skin testing remains the central test to confirm an allergic response. It is minimally invasive and when performed correctly has good reproducibility. Results are easily quantifiable and correlate well with end organ challenge. It is imperative however that technicians who perform the skin tests and the clinicians who order or interpret these tests understand the characteristics of the specific tests they are administering. It is also important that the clinician express skin test results in a manner that allows easy interpretation by another physician.

CONCLUSIONS

Allergists must consider controllable variables that affect skin test results and their interpretation. When not considered, they may be responsible for some of the inaccuracies associated with allergy skin testing.

Skin testing: a survey of allergists

BACKGROUND

In the allergist's office, skin testing remains the central way to confirm allergic response. Although anecdotal data suggest widely varying practices in skin testing by allergists, the diversity and relative frequency of these practices have not been documented.

OBJECTIVE

To determine the extent of the diversity in skin testing practices among allergists.

METHODS

A questionnaire was sent via the Internet to all physician members and fellows of the American College of Allergy, Asthma and Immunology who practice in the United States. This survey explored choice of extract concentrations, skin test device, number and type of tests, method for interpretation and documentation of skin test results, and quality assurance procedures used.

RESULTS

Overall, a significant degree of variability was reported with regard to number of skin tests performed, extract concentrations, skin test devices, interpretation and documentation of results, and quality assurance procedures. The average number of skin prick tests performed ranged from 5.09 (grasses) to 10.9 (trees), whereas the average number of intradermal tests performed ranged from 2.03 (grasses) to 5.6 (perennial). The allergen extract concentrations used for intradermal testing varied widely. Expressed as a dilution of the concentrated extracts, 20.8% use 1:100 dilutions, 10.3% use 1:500 dilutions, and 59.4% use 1:1,000 dilutions. Significant variability also occurred regarding devices and the technique with which the devices were used. Most clinicians (92.1%) used the most concentrated extract available for skin prick testing. For reporting the results of skin testing, 53.8% used a 0 to 4+ scale, and only 28.3% measured orthogonal diameters. Of those using a 0 to 4+ scale, two thirds related the results to the size of the histamine control. Quality assurance testing was reportedly performed by 61.2% of responders. However, less than 10% of responders used an objective test protocol for this purpose.

CONCLUSIONS

This survey highlights some of the areas that allergists can improve on in the use and reporting of skin tests.

Reproducibility of skin testing and serum venom specific IgE in Hymenoptera venom allergy

BACKGROUND

The decision regarding an immunotherapy regimen for venom-allergic patients is based on the results of skin testing and serum venom specific IgE measurements. However, their reliability has been questioned, and their reproducibility has not been examined.

OBJECTIVE

To evaluate the reproducibility and reliability of the results of skin testing and serum venom specific IgE measurement in venom-allergic patients.

METHODS

Patients with a systemic reaction after an insect sting were evaluated twice, 2 to 6 weeks apart, by intradermal skin tests and by determination of serum venom specific IgE to Hymenoptera venoms.

RESULTS

Thirty-five patients were evaluated 1 to 168 months (mean, 23 months) after the sting reaction. Reproducibility of skin test results for all venoms at the 2 sessions was found in 23 patients (66%). Reproducibility of venom specific IgE results for all venoms was found in 16 (59%) of 27 patients from whom 2 blood samples were available for evaluation. Concordance between skin test and venom specific IgE results for all venoms was found in 30 (51%) of 59 samples available for evaluation.

CONCLUSIONS

The reproducibility of venom skin test and serum venom specific IgE results is relatively poor. It is common practice for therapeutic decisions regarding venom immunotherapy to be based on a single diagnostic evaluation. Consequently, many patients are either overtreated or undertreated. Better diagnostic methods are required in venom allergy.

Automated measurement of skin prick tests: an advance towards exact calculation of wheal size

BACKGROUND

Using the Khoros image processing software environment, we developed a software-based system capable of extracting wheal size from skin prick tests (SPTs) in mm(2) for research and routine purposes.

METHODS

At 20 min, the outlines of up to 20 wheals were marked with a pen and transferred with translucent adhesive tapes to a white paper form carrying predefined markings. The form was scanned at 200 dpi. The software automatically analysed the scanned image and calculated the sizes of the wheals. In a pilot study, serial SPTs with histamine in increasing dilutions were performed in 12 healthy volunteers in duplicate on both volar forearms. We matched the application results with a reference created from the scanned pictures.

RESULTS

Bland-Altman analysis showed reference and software calculation reaching very high agreement. The comparison of reference/software resulted in a low centred coefficient of variation (COV) of 11.9%. This was superior to the conventional measurement of horizontal (COV 37.9%) or maximal/minimal diameter (COV 25.9%).

CONCLUSION

We present an accurate tool for exactly calculating SPT wheal size in mm(2).

Allergen skin weal/radioallergosorbent test relationship in childhood populations that differ in histamine skin reactivity: a multi-national survey

BACKGROUND

Histamine skin reactivity (HSR, the dimension of the skin weal elicited by histamine 10 mg/mL) is a variable that differs in children from different European countries and increases over time in the same place (Italy).

OBJECTIVE

In this epidemiologic study, we investigated to what extent differences in HSR influence the relationship between positive allergen skin prick tests (ASPTs) and serum-specific IgE concentrations.

METHODS

Between October 2001 and February 2002, 591 unselected 9-10-year-old schoolchildren drawn from five small towns in central Poland (Starachowice), central Italy (Ronciglione, Guardea) and Libya (Al-Azyzia, near the Mediterranean sea and Samno, 900 km south of the coast) were analysed for histamine, common ASPT and for serum total and specific IgE.

RESULTS

HSR differed markedly in children from the three countries (Libya>Italy>Poland) whereas serum total IgE concentrations remained the same. The prevalence of children with measurable serum specific IgE (> or = 0.35 kU) or with a positive ASPT for five common allergens was high in Italy, lower in Poland and far lower in Libya. A 3-mm ASPT weal corresponded to a serum-specific IgE concentration that was two to threefold higher in children with low HSR compared with children with high HSR (P = 0.008).

CONCLUSION

These findings suggest that HSR--a variable that differs in schoolchildren populations from the three countries studied--independently influences the results of ASPT and its influence should be considered when ASPT are assessed in international studies. The HSR differences found in the populations reported here probably reflect a complex, dynamic, environmental interaction that should be monitored in the different parts of the world.

Adding allergy to your practice

The ability to blend the management of allergic disease into the general treatment of head and neck disease is core to the otolaryngologist's role as regional specialist of the upper aerodigestive tract. Allergy training is now considered an integral component of the residency curriculum established by the American Board of Otolaryngology. By obtaining any needed additional training through organizations such as the AAOA and by validating that education by obtaining fellowship status in the AAOA, the postgraduate otolaryngologist who adds allergy to his or her practice will find the techniques to be safe, effective, and of great benefits to patients.

23. Clinical laboratory assessment of IgE-dependent hypersensitivity

This chapter reviews clinical and laboratory analyses that aid in the diagnosis and management of human allergic (IgE-dependent) diseases. The diagnostic algorithm for immediate-type hypersensitivity begins with a thorough clinical history and physical examination. Once signs and symptoms compatible with an allergic disorder have been identified, a skin test and/or blood test for allergen-specific IgE antibodies may serve as primary confirmation to strengthen the diagnosis. Puncture and intradermal skin testing provide a biologically relevant immediate-type hypersensitivity response in the skin, with resultant wheal and flare reactions within 15 minutes of allergen application. Bleeding, dermatographism, and antihistamines may confound the quality of the skin test. Allergen-specific IgE antibody may also be detected in the blood using a radioallergosorbent test (RAST). Nonisotopic "second-generation" RAST-type assays have evolved to provide more quantitative, sensitive, precise IgE antibody results. In vivo provocation tests may serve as secondary confirmatory tests when the clinical history is discordant with a primary IgE antibody test result. The multiallergen screen is a qualitative RAST-type assay that detects specific IgE antibody to approximately 15 allergens that evoke a large majority of aeroallergen or food-related allergic disorders. Other useful serological assays performed in the diagnostic allergy laboratory include total serum IgE, Hymenoptera venom-specific IgG antibody, IgG precipitins for organic dusts, mast cell tryptases, and the venom RAST inhibition test. Above all, in vivo or laboratory confirmatory test results that are inconsistent with the clinical history should be repeated as for any laboratory assessment.