Evaluation of devices for skin prick testing

A comparison of caregiver-reported snoring and objective snoring in children from urban neighborhoods

OBJECTIVE

Sleep Disordered Breathing (SDB) is both prevalent and under-recognized in pediatric minority populations. Recognition of SDB is often triggered by symptoms of caregiver-reported snoring. However, the validity and utility of caregiver reports likely vary across populations. Our objective is to assess the association between caregiver-reported snoring and objectively recorded snoring in a low-income urban community and explore factors associated with agreement between objective and subjective snoring.

METHODS

169 6 to 12 year old participants underwent at-home sleep studies with a WatchPAT device as part of the Environmental Assessment of Sleep in Youth (EASY) cohort study. Differences in subjective snoring, objective snoring, and concordance between subjective and objective snoring based on socioeconomic and clinical characteristics were assessed.

RESULTS

The sample had a high proportion of non-white (78.9 %) and low income (39.6 %) children. Caregivers reported snoring for 20.7 % of the children and snoring was measured objectively for 21.9 %. Of those with objective snoring, only 29.7 % were identified as snorers by caregiver report (sensitivity: 0.30; specificity: 0.82). Primary Spanish language and co-sleeping were associated with increased caregiver reported snoring, and allergy was associated with increased objective snoring. Older child age and normal range BMI percentile were associated with higher concordance between caregiver and objective snoring.

CONCLUSIONS

Among a community-based, predominantly minority sample, caregiver-reported snoring resulted in under-estimation of prevalence of objectively assessed snoring. Reliance on caregiver report may poorly identify children with snoring or SDB in clinical practice.

Diagnostic accuracy of vaccine and vaccine excipient testing in the setting of allergic reactions to COVID-19 vaccines: A systematic review and meta-analysis

For persons with immediate allergic reactions to mRNA COVID-19 vaccines, skin testing (ST) to the vaccine/excipients (polyethylene glycol[PEG] and polysorbate 80 [PS]) has been recommended, but has unknown accuracy. To assess vaccine/excipient ST accuracy in predicting all-severity immediate allergic reactions upon re-vaccination, systematic review was performed searching Medline, EMBASE, Web of Science, and the WHO global coronavirus database (inception-Oct 4, 2021) for studies addressing immediate (≤4 h post-vaccination) all-severity allergic reactions to 2nd mRNA COVID-19 vaccination in persons with 1st dose immediate allergic reactions. Cases evaluating delayed reactions, change of vaccine platform, or revaccination without vaccine/excipient ST were excluded. Meta-analysis of diagnostic testing accuracy was performed using Bayesian methods. The GRADE approach evaluated certainty of the evidence, and QUADAS-2 assessed risk of bias. Among 20 studies of mRNA COVID-19 first dose vaccine reactions, 317 individuals underwent 578 ST to any one or combination of vaccine, PEG, or PS, and were re-vaccinated with the same vaccine. Test sensitivity for either mRNA vaccine was 0.2 (95%CrI 0.01-0.52) and specificity 0.97 (95%CrI 0.9-1). PEG test sensitivity was 0.02 (95%CrI 0.00-0.07) and specificity 0.99 (95%CrI 0.96-1). PS test sensitivity was 0.03 (95%CrI 0.00-0.0.11) and specificity 0.97 (95%CrI 0.91-1). Combined for use of any of the 3 testing agents, sensitivity was 0.03 (95%CrI 0.00-0.08) and specificity was 0.98 (95%CrI 0.95-1.00). Certainty of evidence was moderate. ST has low sensitivity but high specificity in predicting all-severity repeat immediate allergic reactions to the same agent, among persons with 1st dose immediate allergic reactions to mRNA COVID-19 vaccines. mRNA COVID-19 vaccine or excipient ST has limited risk assessment utility.

Thermography based skin allergic reaction recognition by convolutional neural networks

In this work we present an automated approach to allergy recognition based on neural networks. Allergic reaction classification is an important task in modern medicine. Currently it is done by humans, which has obvious drawbacks, such as subjectivity in the process. We propose an automated method to classify prick allergic reactions using correlated visible-spectrum and thermal images of a patient’s forearm. We test our model on a real-life dataset of 100 patients (1584 separate allergen injections). Our solution yields good results—0.98 ROC AUC; 0.97 AP; 93.6% accuracy. Additionally, we present a method to segment separate allergen injection areas from the image of the patient’s forearm (multiple injections per forearm). The proposed approach can possibly reduce the time of an examination, while taking into consideration more information than possible by human staff.

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.

Fine-tuning the use of a skin prick test device

BACKGROUND

Skin prick tests (SPTs) are the gold standard for the diagnosis of IgE-mediated allergic diseases. Newly introduced devices have different results in performance. This study aimed to provide data for sensitivity, reproducibility, and acceptability of a new SPT device by using different techniques.

METHODS

The study was conducted in 4 sections. Different application techniques were evaluated. In the first section, a drop of histamine/saline was put by vial (V). In the second section, it was taken from a well via the test device (W). ALK® Lancet served as a reference in both sections. The techniques were as follows; 1) apply vertical pressure (VP/WP), 2) apply vertical pressure and rotate 90° clockwise (VC/WC), 3) apply vertical pressure and rotate 90° clockwise and then counter-clockwise (VCC/WCC). Pain assessment was performed by using the Wong-Baker FACES Pain Rating Scale. Different histamine concentrations were transferred from the well by the Oryum device and applied as WC in section 3. Lancet and Oryum-WP were compared in terms of time and allergen adequacy in section 4.

RESULTS

In the first section the sensitivity of all techniques for Oryum and lancet were 100%. The false positivity of Oryum-VP, WP and lancet were found 0%. The Oryum-VP technique was found the best for intrapatient coefficient of variation (CV) (10.72%) (p < 0.001). The interpatient CV was similar in the Oryum-VP, VC, VCC and lancet techniques and was different from the Oryum-WP (p < 0.001). In the second section, all Oryum techniques yielded high sensitivities (100%). False-positive results were obtained more in Oryum-WC and WCC. Oryum-WP technique had the lowest pain score. In the 3rd section, the high positive correlation between histamine concentrations was observed (r = 0.731). In terms of time and allergen adequacy, Oryum-WP was superior to the lancet.

CONCLUSION

Oryum-VP and WP techniques are reliable, tolerable and comparable with the lancet technique.

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.

Allergy Testing

Allergic diseases are common in outpatient primary care. Allergy testing can guide management to determine allergy as a cause of symptoms and target therapeutic interventions. This article provides a review of common methods of allergy testing available so that physicians may counsel and refer patients appropriately. Immediate-type hypersensitivity skin tests can be used for airborne allergens, foods, insect stings, and penicillin. Radioallergosorbent testing can be used to evaluate immediate-type hypersensitivity. Delayed-type hypersensitivity or patch-type skin tests are used in patients with suspected contact dermatitis.

Implementation of a Standardized Clinical Assessment and Management Plan (SCAMP) for Food Challenges

BACKGROUND

Oral food challenges (OFCs) are routinely used to confirm ongoing food allergy. Serum-specific IgE (sIgE) and skin prick testing (SPT) are imperfect predictors of which patients will pass OFCs.

OBJECTIVE

The objective of this study was to describe the design and implementation of a Standardized Clinical Assessment and Management Plan (SCAMP) to study and iteratively improve sIgE and SPT thresholds to determine when and where to conduct OFCs for patients.

METHODS

Allergists consulted recommended sIgE and SPT thresholds when ordering challenges although diversions were permitted. Criteria were iteratively improved after periodic analyses of challenge outcome and diversions.

RESULTS

Over 3 years, allergists ordered 2368 food challenges for 1580 patients with histories of IgE-mediated reactions to food: 1386 in an outpatient clinic and 945 in a higher resource infusion center. Reactions to challenge were observed in 13% of clinic and 23% of infusion center challenges. Six patients challenged in clinic required treatment with epinephrine compared with 22 in the infusion center. The need for epinephrine was more common in patients with asthma-5% of asthmatic patients required epinephrine compared with 1% of nonasthmatic patients (P < .01). Recommended sIgE and SPT thresholds were incrementally changed and, using the control chart methodology, a significant decrease was noted in the proportion of challenges ordered in the higher resource location.

CONCLUSIONS

By setting and continually refining sIgE and SPT recommendations using the SCAMP method, allergists can better determine the risk of severe reaction and triage patients to the appropriate setting for an OFC.

The Lancet Weight Determines Wheal Diameter in Response to Skin Prick Testing with Histamine

BACKGROUND

Skin prick test (SPT) is a common test for diagnosing immunoglobulin E-mediated allergies. In clinical routine, technicalities, human errors or patient-related biases, occasionally results in suboptimal diagnosis of sensitization.

OBJECTIVE

Although not previously assessed qualitatively, lancet weight is hypothesized to be important when performing SPT to minimize the frequency of false positives, false negatives, and unwanted discomfort.

METHODS

Accurate weight-controlled SPT was performed on the volar forearms and backs of 20 healthy subjects. Four predetermined lancet weights were applied (25 g, 85 g, 135 g and 265 g) using two positive control histamine solutions (1 mg/mL and 10 mg/mL) and one negative control (saline). A total of 400 SPTs were conducted. The outcome parameters were: wheal size, neurogenic inflammation (measured by superficial blood perfusion), frequency of bleeding, and the lancet provoked pain response.

RESULTS

The mean wheal diameter increased significantly as higher weights were applied to the SPT lancet, e.g. from 3.2 ± 0.28 mm at 25 g to 5.4 ± 1.7 mm at 265 g (p<0.01). Similarly, the frequency of bleeding, the provoked pain, and the neurogenic inflammatory response increased significantly. At 265 g saline evoked two wheal responses (/160 pricks) below 3 mm.

CONCLUSION AND CLINICAL RELEVANCE

The applied weight of the lancet during the SPT-procedure is an important factor. Higher lancet weights precipitate significantly larger wheal reactions with potential diagnostic implications. This warrants additional research of the optimal lancet weight in relation to SPT-guidelines to improve the specificity and sensitivity of the procedure.

Sensitivity and Specificity of Prick and Intradermal Testing in Predicting Response to Nasal Provocation with Timothy Grass Antigen

OBJECTIVE: Examine the efficacy of epicutaneous and intradermal testing in predicting response to nasal provocation with timothy antigen.

STUDY DESIGN AND SETTING: Prospective study. Subjects were tested with Multi-Test II (MT). Subjects with negative wheals were tested with a 1:500 intradermal injection of timothy. They had baseline assessment of nasal cross-sectional area (CSA) using acoustic rhinometry and underwent nasal provocation with increasing timothy concentrations. CSA was assessed and nasal visual analog scale (VAS) completed with each concentration.

RESULTS: Sensitivity and specificity of MT in predicting nasal response to provocation were 87% and 86%. Intradermal testing increased sensitivity to 93%. Hierarchical linear modeling (HLM) demonstrated that subjects positive to skin testing had significant reductions in CSA and worsening VAS scores with increasing concentrations of nasally delivered antigen.

CONCLUSION AND SIGNIFICANCE: Epicutaneous testing with the Multi-Test II offers 87% sensitivity and 86% specificity in assessing timothy grass reactivity.

Skin testing versus in vitro testing in the evaluation of aeroallergy: The great debate

When one examines reviews regarding diagnostic allergy testing, it generally is noted that the advantage of skin testing is that it uses testing to an end organ, is less expensive, is more sensitive, and provides immediate results, which are easily visualized by the patient. In the case of in vitro testing, it is thought to be more helpful for patients with dermographia or widespread dermatitis, is not affected by H1 or H2 antagonists, and is thought to be safer than skin testing. This may not be entirely correct because studies actually demonstrated phlebotomy to be associated with more morbidity than skin-prick testing. Other concerns regarding both tests include allergen quality, the need from proficiency testing, and the fact that these tests should be used for corroborating a diagnosis as opposed to a screening test for allergy.

Optimizing the use of a skin prick test device on children

BACKGROUND

Studies comparing skin prick test (SPT) devices have revealed varying results in performance and there is little known about their use on children.

METHODS

We performed 2 complementary studies to test the sensitivity, reproducibility and acceptability of commercially available SPT devices (Stallerpoint, Antony, France) using different application techniques. In the first part, histamine/saline was put on as a drop by use of a vial (V), and in the second part it was transferred from a well with the aid of the test device (W). The techniques were as follows: apply vertical pressure (Stallerpoint-VP or Stallerpoint-WP), apply vertical pressure with 90° clockwise rotation (Stallerpoint-VC or Stallerpoint-WC) and apply vertical pressure with 90° clockwise and counter-clockwise rotations (Stallerpoint-VCC or Stallerpoint-WCC). For comparison, ALK Lancet was used with a technique of 'drop and apply vertical pressure'.

RESULTS

In the first part, sensitivities of the Stallerpoint-VC (96.6%), Stallerpoint-VCC (95.5%) and ALK Lancet (93.2%) techniques were superior (p < 0.001) to the other Stallerpoint-VP and Stallerpoint-WP techniques (76.1 and 46.6%). Intrapatient coefficient of variation (CV) values were 15.0, 18.9, 15.4, 22.4 and 48.5%, respectively. Interpatient CV ranged between 22.8 and 55.1%. In the second part, the Stallerpoint-WC (98.8%), WCC (97.5%) and ALK Lancet (98.8%) techniques yielded high sensitivities, whereas the sensitivity of Stallerpoint-WP (28.7%) was very low. There were false-positive reactions in the Stallerpoint-VCC and WCC techniques.

CONCLUSION

In children, the SPT technique was found to be as important as the testing device. Stallerpoint-VC and WC techniques are reliable, tolerable and comparable with the ALK Lancet technique.

Variability in skin prick test results performed by multiple operators depends on the device used

Background

The variability of skin prick test results when carried out by multiple users has not previously been assessed across different devices or between different sites on the body. Such multiuser variability has important implications for clinical practice.

Objectives

We assessed the variability of measurements from 4 commonly used single-headed skin test devices when used by multiple operators and examined whether the variability in performance was different on the back compared with the forearm.

Methods

Eight adult volunteer "operators" were trained in the use of 4 devices: Greer Pick, Quintip, Stallergenes Lancet, and Feather Lancet. Each operator performed a histamine skin prick test with all devices on the backs and forearms of 5 volunteer "receivers." Variability in results was assessed using a multilevel (random effects) regression model.

Results

After controlling for variation between users and receivers, the residual variability or "measurement error" was least for the Stallergenes Lancet, closely followed by the Quintip. The Greer Pick had the greatest variability. There was greater variability in measurements on the arm compared with the back.

Conclusions

The devices using the "puncture" method (Stallergenes Lancet, Quintip) provide less variability in results than those using a "prick" method when carried out by multiple users (Greer Pick and Feather Lancet). Testing on the back also gives less variable results compared with the arm.

Allergic rhinitis

Allergic rhinitis is a costly disease associated with significant morbidity. It impacts the quality of life of millions of individuals, particularly in industrialized nations, and it is on the rise. Lost productivity and total healthcare expenditure exceeds several billion dollars annually in the United States, with an estimate of >$6 billion spent on prescription medications alone. It is also associated with asthma and other atopic conditions, sinusitis, otitis media, and sleep apnea. Primary care physicians should be well adept at recognizing and initiating empiric first-line therapy for chronic rhinitis. Allergen avoidance, topical nasal steroids, and antihistamines may be sufficient for some patients. In most cases, referral to a board-certified allergy specialist for skin testing and targeted management is indicated. It is essential to make sure that patients abstain from using antihistamines at least 1 week prior to reporting to the allergist for skin testing in order to avoid false-negative results. Traditional subcutaneous allergen immunotherapy, when performed by an experienced allergist, affords relief in >75% of cases. The growing armament of treatment options for refractory allergic rhinitis includes oral and sublingual immunotherapy, recombinant allergens, conjugated DNA vaccines, and anti-immunoglobulin E monoclonal antibody.

Comparison of five techniques of skin prick tests used routinely in Europe

BACKGROUND

Skin prick tests represent indispensable tools in allergy, even more than 30 years after their introduction in clinical practice.

OBJECTIVES

Few recent European studies have focused on this topic and we thus wanted to compare the instruments most often used today.

METHODS

Four instruments were investigated: the 23G intravenous (IV) needle, the ALK Lancet, the Stallergenes (STG) Prick Lancet and the Stallerpoint(®) (using two different methods). Sensitivity, reproducibility, and acceptability were evaluated. In 22 subjects, we calculated the sensitivity and reproducibility (both intra- and interpatient) of these methods by testing the positive control five times. In 50 subjects, we tested the single-blind acceptability of these same five techniques.

RESULTS

In terms of sensitivity, the IV needle (100%) and metal lancets (96% for the ALK Lancet and 98% for the STG Prick Lancet) were superior (P < 0.01) to the two Stallerpoint(®) methods (20% and 57%). Intrapatient reproducibility was 16.2%, 14.6%, 15.0%, 97.1% and 18.1%, respectively. The instruments that were best tolerated by the patients were the IV needle and the two metal lancets.

CONCLUSION

Metal needles and/or lancets are the tools of choice for skin prick testing.

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.

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.

Pearls and pitfalls of allergy diagnostic testing: report from the American College of Allergy, Asthma and Immunology/American Academy of Allergy, Asthma and Immunology Specific IgE Test Task Force

The intended purpose of this monograph is to provide a general overview of allergy diagnostics for health care professionals who care for patients with allergic disease. For a more comprehensive review of allergy diagnostic testing, readers can refer to the Allergy Diagnostic Practice Parameters. A key message is that a positive allergy test result (skin or blood) indicates only the presence of allergen specific IgE (called sensitization). It does not necessarily mean clinical allergy (ie, allergic symptoms with exposure). It is important for this reason that the allergy evaluation be based on the patient's history and directed by a health care professional with sufficient understanding of allergy diagnostic testing to use the information obtained from his/her evaluation of the patient to determine (1) what allergy diagnostic tests to order, (2) how to interpret the allergy diagnostic test results, and (3) how to use the information obtained from the allergy evaluation to develop an appropriate therapeutic treatment plan.

Dissociation between the prevalence of atopy and allergic disease in rural China among children and adults

BACKGROUND

The prevalence of allergic diseases is increasing worldwide, but the reasons are not well understood. Previous studies suggest that this trend might be associated with lifestyle and urbanization.

OBJECTIVE

We sought to describe patterns of sensitization and allergic disease in an unselected agricultural Chinese population.

METHODS

The data were derived from a community-based twin study in Anqing, China. Skin prick tests were performed to foods and aeroallergens. Atopy was defined as sensitization to 1 or more allergens. Allergic disease was ascertained by means of self-report. The analysis was stratified by sex and age (children [11-17 years] and adults [>or=18 years]) and included 1059 same-sex twin pairs.

RESULTS

Of 2118 subjects, 57.6% were male (n = 1220). Ages ranged from 11 to 71 years, and 43.3% were children (n = 918). Atopy was observed in 47.2% (n = 999) of participants. The most common sensitizing foods were shellfish (16.7%) and peanut (12.3%). The most common sensitizing aeroallergens were dust mite (30.6%) and cockroach (25.2%). Birth order and zygosity had no effect on sensitization rates. Multivariate logistic regression models revealed that risk factors for sensitization include age for foods and sex for aeroallergens. The rates of food allergy and asthma were estimated to be less than 1%.

CONCLUSIONS

Atopic sensitization was common in this rural farming Chinese population, particularly to shellfish, peanut, dust mite, and cockroach. The prevalence of allergic disease, in contrast, was quite low.

Diagnostic Evaluation of Inhalant Allergies: A Cost-effectiveness Analysis

Background

The purpose of this study was to compare the cost-effectiveness of modified quantitative testing (MQT), intradermal dilutional testing (IDT), and in vitro allergy testing as diagnostic methods used in the management of patients with suspected IgE-mediated inhalant allergies.

Methods

A systematic review was conducted to determine key statistics for analysis, such as prevalence of disease, and sensitivity and specificity of each diagnostic modality. Costs were calculated based on charges from distribution companies to providers. A deterministic cost-effectiveness analysis then was conducted using a decision tree model to evaluate the various diagnostic strategies. After identifying results at baseline, we performed a sensitivity and threshold analysis to assess the strength of recommendations.

Results

At an allergic rhinitis prevalence of 20%, MQT dominated IDT and in vitro testing, with 85 people correctly diagnosed at a baseline total cost of $6630 for the 100 patients tested. Although in vitro testing had the highest effectiveness, it had an incremental cost-effectiveness ratio of $3185. The results were sensitive to changes in the prevalence, costs, and sensitivities and specificities of the different modalities.

Conclusion

The prevalence of allergic rhinitis is high and rising according to many studies, leading to a growing population of patients requiring allergy testing. Not only does today's medical community want effective health interventions, but also there is pressure to make health care cost efficient. This study looks at the cost-effectiveness of various diagnostic allergy tests. In our model, we found MQT to be the most cost-effective method of diagnosing allergic disease.

Comparison of the Multi-Test II and Skintestor Omni allergy skin test devices

BACKGROUND

Different devices for percutaneous allergy skin testing have demonstrated statistically and clinically significant differences in performance characteristics.

OBJECTIVE

To compare 2 Food and Drug Administration-approved multihead allergy skin testing devices: Multi-Test II (Lincoln Diagnostics) and Skintestor Omni (Greer Laboratories).

METHODS

Skin tests with glycerinated histamine (6-mg/mL base) and glycerinated saline were applied to 31 adults using Multi-Test II on the volar surface of one forearm and Skintestor Omni on the opposite forearm.

RESULTS

Data were accumulated from 155 histamine sites and 93 negative control sites for each device. Using cutoff wheal sizes of 5 vs 3 mm inclusive to define a positive result, Multi-Test II sensitivity remained at 100%, but specificity increased from 74% to 97%, whereas Skintestor Omni sensitivity decreased from 94% to 87%, and specificity increased from 58% to 88%. For Multi-Test II vs Skintestor Omni, histamine mean (SD) wheal sizes were 9.23 (1.37) vs 7.74 (2.83) mm (P < .001), mean coefficients of variance were 14.8% vs 36.6%, and pooled estimates of variance were 0.642 vs 6.974. Multi-Test II produced similar histamine wheal sizes regardless of test head position used, whereas Skintestor Omni produced statistically significantly smaller wheals at certain test head positions.

CONCLUSIONS

Multi-Test II had higher sensitivity and specificity than Skintestor Omni and produced reproducible wheal sizes from all test head positions. Because some Skintestor Omni test head positions produced significantly smaller histamine wheal sizes, skin testing using this device might result in underdiagnosis of allergy.

Combining skin prick, immediate skin application and specific-IgE testing in the diagnosis of peanut allergy in children

Previous studies have suggested various diagnostic cut-offs of allergy tests for the diagnosis of clinical peanut allergy in children. There are few data relating to the use of combinations of these tests in children. We aimed to determine the validity of previously reported diagnostic cut-off levels of peanut allergen skin tests and peanut specific-immunoglobulin (Ig) E, as well as the usefulness of combinations of these, for predicting clinical peanut allergy in our Allergy Clinic. Children attending the Allergy Clinic with a positive peanut skin prick test (SPT; n = 84) were included in the study. Immediate skin application food tests (I-SAFT) using 1 g of peanut butter (positive if any wheals were detected at 15 min), peanut specific-IgE levels and open-label peanut food challenges were performed. Fifty-two of 85 peanut challenges were positive. Skin prick test specificity was 67% at >or=8 mm and 100% at >or=15 mm. The I-SAFT was 82% specific. A peanut specific-IgE level of 0.37 kU/l was 98% sensitive but 33% specific. A level of 10 kU/l was 100% specific. Combinations of a SPT of >or=8 mm with a positive I-SAFT and a peanut specific-IgE >or=0.37 kU/l were 88% specific with a sensitivity of 38%. Using challenge outcomes as the standard, available in vitro and in vivo diagnostic tests for peanut allergy have poor sensitivity and specificity and combining them does not significantly improve their clinical usefulness. Previously described diagnostic cut-off levels do not have general applicability. Allergy practitioners may need to interpret results of allergy tests in the context of their own practices.

The New Zealand Asthma and Allergy Cohort Study (NZA2CS): assembly, demographics and investigations

Background

Asthma and allergy are highly prevalent in industrialised countries. Longitudinal and cross-sectional studies have identified a number of potential risk factors for these conditions, including genetic and environmental factors, with significant gene-environment relationships. Birth cohort studies have been proposed as an important tool to explore these risk factors, particularly exposures in early life that are associated with later disease or protection from disease. This paper describes the establishment of a birth cohort in New Zealand.

Methods

A birth cohort was established in 1996 in Christchurch and Wellington and infants recruited between 1997–2001. Expectant mothers were recruited by midwives. Children and mothers have undergone assessment by serial questionnaires, environmental assessment including mould and allergen exposure, skin-prick testing, and at age six years are undergoing full assessment for the presence of asthma, atopy and allergic disease, including genetic assessment.

Results

A total of 1105 children have been recruited, and the retention rate at fifteen months was 91.4%. 15.2% of the children at recruitment have been identified as Maori. A positive family history of asthma, eczema or hay fever has been reported in 84% of children. All children have now been assessed at fifteen months and 685 children from the cohort have reached age six years and have completed the six year assessment.

Conclusion

The cohort is fully assembled, and assessment of children is well advanced, with good retention rates. The study is well placed to address many current hypotheses about the risk factors for allergic disease and asthma.

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.

The effect of montelukast (10mg daily) and loratadine (10mg daily) on wheal, flare and itching reactions in skin prick tests

Antileukotriene agents are widely used for the treatment of allergic conditions including bronchial asthma and allergic rhinitis. The influence of montelukast on skin reactivity has not been clearly evaluated. The aim of this study was to determine the effect of montelukast on wheal, flare and itching in skin prick tests (SPTs).

METHODS

Fifteen atopic patients (5 women and 10 men) with average age 28.04 (SD+/-8.24) were tested with histamine, codeine, negative control solution and allergen extract (grasses). Montelukast (10mg), loratadine (10mg) or placebo were given to the volunteers for 5 days in a double-blind manner, followed by SPT, with 14 days of wash-out period.

RESULTS

There was no differences in wheal, flare and itching (p=0.205; 0.086 and 0.069, respectively, Wilcoxon rank-sum test) between SPT performed after placebo and wash-out period. The analysis revealed a statistically significant suppression of wheal and flare by loratadine (p<0.05 for all tested solutions). Pre-treatment with montelukast did not influence wheal size (p=0.099, 0.21, 0.066 for histamine, codeine and allergens, respectively), but significantly reduced flare (p=0.005; 0.003; 0.02 for histamine, codeine and allergens, respectively). We found a significant suppression of itching produced by montelukast (p=0.02) and loratadine (p=0.03) as compared to placebo (p=0.068 vs. wash out).

CONCLUSIONS

Our data show a tendency to suppressive effect of montelukast on flare and itching but not on wheal which is basic for SPT interpretation. We conclude that found suppression have little impact on clinical effectiveness of SPT as a diagnostic tool.

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.

Production of interleukin 10 and transforming growth factor beta in concomitant allergy and autoimmunity

BACKGROUND

The immunologic relationship between T(H)1-type autoimmune disorders and T(H)2-type allergic disorders and the role of T-cell regulation in humans is as yet unclear. The regulatory cytokine production capacity of individuals with concomitant allergy and T(H)1-type autoimmunity may provide insight into the role of T-cell regulation in both disorders.

OBJECTIVES

To examine the production capacity of interleukin 10 (IL-10) and transforming growth factor beta (TGF-beta), 2 regulatory cytokines, in individuals with concomitant allergic rhinitis and T(H)1-type autoimmune diagnoses and to compare that capacity with that in individuals with allergic rhinitis only and individuals with neither diagnosis.

METHODS

Seventeen case subjects and 17 age-, sex-, and ethnicity-matched controls with allergic rhinitis only were recruited from an allergy clinic. Fourteen matched controls with neither diagnosis were recruited from the general population. Peripheral blood mononuclear cells were obtained and cultured with and without mitogen stimulation (lipopolysaccharide and phytohemagglutinin). Cytokine levels from culture supernatants were measured by enzyme-linked immunosorbent assay.

RESULTS

Cases with allergic rhinitis and autoimmune diseases had significantly lower unstimulated day 3 IL-10 levels compared with controls with allergic rhinitis only (P = .05) and significantly lower stimulated day 5 TGF-beta levels compared with controls with neither diagnosis (P = .02). Cases had consistently lower regulatory capacity compared with both control groups, as measured by an additive index using IL-10 and TGF-beta levels.

CONCLUSION

Individuals with concomitant allergic rhinitis and T(H)1-type autoimmune disorders have a lower regulatory cytokine production capacity than individuals with allergic rhinitis only and those with neither diagnosis.

Nitric oxide levels and ciliary beat frequency in indigenous New Zealand children

New Zealand children's morbidity from respiratory disease is high. This study examines whether subclinical ciliary abnormalities underlie the increased prevalence of respiratory disease in indigenous New Zealand children. A prospective study enrolled a group of healthy children who were screened for respiratory disease by questionnaire and lung function. Skin-prick tests were performed to control for atopy. Exhaled and nasal NO was measured online by a single-breath technique using chemiluminescence. Ciliary specimens were obtained by nasal brushings for assessment of structure and function. The ciliary beat frequency (CBF) (median CBF, 12.5 Hz; range, 10.4-16.8 Hz) and NO values (median exhaled NO, 5.6 ppb; range, 2.3-87.7 ppb; median nasal NO, 403 ppb; range, 34-1,120 ppb) for healthy New Zealand European (n=58), Pacific Island (n=61), and Maori (n=16) children were comparable with levels reported internationally. No ethnic differences in NO, atopy, or CBF were demonstrated. Despite an apparently normal ciliary beat, the percentage of ciliary structural defects was 3 times higher than reported controls (9%; range, 3.6-31.3%), with no difference across ethnic groups. In conclusion, it is unlikely that subclinical ciliary abnormalities underlie the increased prevalence of respiratory disease in indigenous New Zealand children. The high percentage of secondary ciliary defects suggests ongoing environmental or infective damage.

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.

Bimodal skin reactivity to histamine in atopic children in Singapore: influence of specific sensitizations

Histamine skin prick test (SPT) is used as the 'golden standard' for positive control in in vivo immediate type hypersensitivity testing. The skin reactivity to histamine can, however, be modulated by a bevy of extraneous factors. We aimed to define whether histamine skin reactivity in atopic children in Singapore is influenced by age, ethnic origin, gender, environmental exposure or specific sensitization patterns. A retrospective analysis of children, with specific aeroallergen sensitization (as measured by at least one allergen-specific SPT with a wheal size > 3 mm compared with the negative control) from the outpatient speciality clinic of the KK Children's Hospital, during 06/2002-06/2003. A total of 315 patients were included, 235 (75%) were males, 252 (80%) were Chinese, age mean was 7.7 yr (range: 2-15). Patients were referred to the SPT with a diagnosis of one or more of: allergic rhinitis 287 (91%), asthma 112 (36%) or atopic dermatitis 60 (19%). The mean histamine response showed a bimodal distribution, independent of age, ethnic origin, gender or phenotypical expression of allergic disease. Histamine skin reactivity was higher in atopic patients with polysensitization (mean 5.0 mm vs. 2.9 mm in monosensitized patients, p < 0.001), and in patients with mould sensitization (mean 5.1 mm vs. 3.3 mm in patient not sensitized to moulds, p < 0.001). The presence of passive smoking increased the likelihood of a diminished histamine skin response. Histamine skin response data strongly suggested the presence of two heterogeneous subpopulations. Children with polysensitization and mould sensitization were more likely to show a large significant histamine response, whereas children with passive smoke exposure, showed a diminished skin reactivity to histamine.

Optimal skin prick wheal size for diagnosis of cat allergy

BACKGROUND

The skin prick test is the diagnostic procedure of choice for determination of immediate hypersensitivity. A wheal diameter of 3 mm or larger is generally accepted as the cutoff for a positive test result, although the validity of this assumption has not been rigorously demonstrated.

OBJECTIVE

To determine the skin prick wheal size that best identifies clinical allergy to cat.

METHODS

Forty-five patients referred for evaluation of rhinoconjunctivitis underwent determination of atopic status by skin testing using the Greer Dermapik device and a combination of other modalities, including history, in vitro determination of specific IgE level, and nasal challenge with standardized cat pelt extract. Parameters evaluated before and after nasal challenge included symptom score and nasal lavage tryptase and prostaglandin D (PGD2) levels.

RESULTS

The widely accepted 3-mm wheal for a positive skin test result to cat is highly sensitive but only moderately specific for diagnosis of cat allergy as evaluated by history, specific IgE level, postchallenge symptom score, and tryptase and PGD2 levels. Optimal cutoffs for a positive skin test result to cat based on receiver operating characteristic analysis and 95% positive predictive value were 5.5 mm or greater for each of these parameters. When a true-positive result for cat allergy was defined as a combination of positive history, specific IgE level, postchallenge symptom score, and tryptase and PGD2 levels and a true-negative result as all of these parameters being negative, a 6-mm cutoff was able to distinguish cat allergic from cat nonallergic individuals.

CONCLUSION

In a potentially allergic population undergoing skin prick testing with the Greer Dermapik using standardized extracts, a 3-mm skin prick wheal will overestimate the presence of cat allergy. A 6-mm wheal appears to distinguish those individuals who are cat allergic from those who are not.

Skin Testing in Predicting Response to Nasal Provocation with Alternaria

OBJECTIVE

Examine the efficacy of epicutaneous and intradermal testing in predicting response to nasal provocation with Alternaria antigen.

STUDY DESIGN AND SETTING

Prospective study. Subjects were tested with the Multi-Test II (MT) epicutaneous testing device. Subjects with negative wheals were then tested with a 1:500 weight:volume intradermal injection of Alternaria. They had baseline assessment of nasal cross-sectional area (CSA) using acoustic rhinometry and underwent nasal provocation with increasing Alternaria concentrations. CSA was assessed at each concentration. A nasal allergen provocation score (NAP) of nasal symptoms as well as a nasal visual analogue scale (VAS) were also completed with each concentration.

RESULTS

Sensitivity and specificity of MT in predicting nasal response to Alternaria were poor at 42% and 44%, respectively. The addition of intradermal testing increased sensitivity only modestly to 58%. hierarchical linear modeling analysis demonstrated that subjects positive to Alternaria on skin testing did not show a significant reduction in nasal CSA on acoustic rhinometry or significant elevations in two nasal symptom scores with direct nasal provocation.

CONCLUSION AND SIGNIFICANCE

Skin testing with either epicutaneous or intradermal testing may not be an accurate or sufficient technique in the assessment of Alternaria reactivity. These results suggest that mold allergies may involve more complex immune mechanisms than simply an immunoglobulin (Ig)E mediated type I immediate hypersensitivity response alone. An alternate model for mold sensitivity, as well as modifications in testing methods, may be required in the evaluation of mold allergy.

Comparison of Multi-Test II skin prick testing to intradermal dilutional testing

OBJECTIVES/HYPOTHESIS

Intradermal dilutional testing (IDT) has been considered more sensitive than prick testing for detecting low-level allergies. Multi-Test II is one of the most sensitive and reproducible prick testing methods available. This study compares Multi-Test II prick testing with IDT.

DESIGN

Retrospective chart review and data analysis on patients who had allergy testing with both Multi-Test II and IDT.

SETTING

Outpatient allergy clinic in the otolaryngology department of an academic tertiary care medical center.

POPULATION

Forty adult patients had complete allergy testing with both Multi-Test II and IDT for a standard panel of twelve antigens between January 2002 and April 2002.

INTERVENTION

Analysis and comparison of test results on Multi-Test II and IDT for each antigen separately and across all antigen tests together.

RESULTS

Forty patients had complete testing for all antigens during the time period for the study. Six of these patients did not react to the positive control on Multi-Test II and were eliminated from the main analysis. Of the 34 patients included in the main analysis, all were positive for at least one antigen on IDT; one half (17/34) were negative for all antigens on Multi-Test II. A significantly greater number of patients were positive on IDT than Multi-Test II for all antigens except dog (P < 0.05). There was a statistically significant correlation between IDT endpoint and Multi-Test II score for several antigens (P < 0.05). Of 408 total antigen tests performed, 339 (83.1%) were negative on Multi-Test II. Of these 339 negative Multi-Test II tests, 148 (43.7%) were negative on IDT and 191 (56.3%) were positive on IDT; 174/339 (51.3%) had an IDT endpoint of 2 or 3 and 17/339 (5.0%) had an IDT endpoint > or = 4. A significantly greater number of antigen tests were positive on IDT than on Multi-Test II (P < 0.001). The overall Spearman correlation coefficient between IDT endpoint and Multi-Test II score was 0.370 (P < 0.001).

CONCLUSION

Patients were more likely to have a positive test on IDT than on Multi-Test II. IDT therefore may be a more sensitive testing technique for inhalant allergies than Multi-Test II prick testing. In addition, Multi-Test II score may not be a good predictor of IDT endpoint. Although a statistically significant correlation is demonstrated between Multi-Test II score and IDT endpoint, the correlation coefficient is low enough that clinical application may not always be safe or appropriate. The clinical significance of positive IDT results in the presence of negative Multi-Test II results is not known.

Cutaneous testing for allergy diagnosis: comparison of methods in common use

Practitioners who treat allergic patients must be familiar with the tests that are available to assist them in establishing the diagnosis. They must also understand the strengths and weaknesses of each of the techniques, devices, and grading systems at their disposal and that there is no criterion standard skin test. This article discusses the various techniques used in skin testing for allergy, their grading systems, and their advantages and disadvantages.

Current in vivo and in vitro screens for inhalant allergy

Screening for inhalant allergy requires the use of a rapid, accurate, cost-effective methodology for the detection of the presence or absence of allergic responsiveness. In vivo and in vitro methods have been demonstrated to be sensitive and specific in the diagnosis of inhalant allergy, even with panels as small as seven or eight antigens. There is good concurrence between skin testing techniques and various serum measures of specific IgE, and both methods can be used effectively for screening inhalant allergy, although per-test costs for in vitro methods remain higher than comparable costs for skin testing [28]. Although the rapidity of both methods is acceptable, skin testing allows immediate observation and interpretation of test results, whereas all in vitro methods involve serum processing that delays results for hours to days. In general, both in vitro methods and epicutaneous testing with a device such as the Multi-Test II offer the clinician effective techniques in screening for inhalant allergy. Each technique has benefit and can be used in both primary care practices and in specialists' offices. The choice of the primary technique to be used for screening depends on the type of practice, the practice's familiarity with skin testing, the geographic region, and the relevant payer mix. A review of the relevant research on allergy screening suggests that the number of antigens used should be in the range of 8 to 12 and should include representative allergens from all the significant classes for the specific geographic [table: see text] region. This screen would probably contain one or two grasses, weeds, and trees, two or three molds, cat allergen, and one dust mite allergen. A sample panel is demonstrated in Box 6. It is important to recognize that the diagnosis and treatment of inhalant allergy is a fluid process. In patients who have negative allergy screens but for whom suspicion of inhalant allergy remains high, additional testing with ID techniques is sometimes indicated. This procedure might be suggested in patients for whom there is a high suspicion of mold allergy or who have unusual inhalant exposures. These individuals may represent a failure of the screening process and require additional testing. In these unusual cases, the judgment of the otolaryngic allergist is critical in guiding this further diagnostic work-up. The use of screening procedures for the diagnosis of inhalant allergy provides a rapid, accurate, and cost-effective method for evaluating patients with a history suggestive of allergic disease. Research suggests that a screening panel has strong clinometric properties and has both sensitivity and specificity in excess of 95%. It is statistically unlikely that a patient with negative findings to an allergy screen will demonstrate clinically significant inhalant allergy.

Cost analysis of employing multi-test allergy screening to guide serial endpoint titration (SET) testing versus SET alone

OBJECTIVE: We analyzed the cost differences between 2 different modalities of allergy testing.

STUDY DESIGN AND SETTING: Material costs, labor costs, and overhead expenditures were compared for 2 different allergy-testing algorithms. Fifty patients were placed in each group. The first group was tested for 14 allergens and 2 control substances by using multi-test II. These patients were compared with 50 patients tested for similar allergens and control substances by using serial end-point titration.

RESULTS: The initial round of tests with serial endpoint titration was nearly 3 times as costly as the multi-test for the 14 allergens and 2 control substances.

CONCLUSION AND SIGNIFICANCE: Multi-testing is a cost-effective initial testing modality that can screen out negative results and enable the identification of positive reactions. These results could then be further investigated by using serial endpoint titration or RAST to quantify the patient's sensitivity and establish a starting dose for immunotherapy.

Comparison of standard and modified SPT method

BACKGROUND

The aim of our study was to compare clinical significance and economical factors of commonly used standard skin prick tests (SPT) method with new, modified and more handy way of performing SPT.

METHODS

Twenty-one subjects [with an average age of 23 years (SD +/- 2.72)] with known sensitivity to examined allergen extracts were tested with histamine, negative control solution and standard allergen extracts (Allergopharma, Reinbeck, Germany). SPT were applied to the volar surface of randomly assigned forearm with two methods: standard technique using lancet needle to prick the epidermis under small drop of extract and tested method using lancet needle which was dipped in extract before prick. In this method all extracts were placed in marked, small, plastic chambers.

RESULTS

Mean wheal to histamine was 5.49 (standard method) and 5.01 (modified method). There was no statistical difference between the standard and modified method for size of wheal to histamine (P = 0.654) and to allergen extracts (n = 36, P = 0.824, Wilcoxon test). Economical analysis revealed that examined SPT technique is cheaper than standard method.

CONCLUSION

Examined method may be considered to be an alternative for performing SPT as it is safe, cheaper and more convenient than standard technique.

SUMMARY STATEMENT

Comparison of standard and modified SPT method revealed the new method to be more economical.