Comparison of the sensitivity and precision of four skin test devices

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.

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.

Diagnostic tools in Rhinology EAACI position paper

This EAACI Task Force document aims at providing the readers with a comprehensive and complete overview of the currently available tools for diagnosis of nasal and sino-nasal disease. We have tried to logically order the different important issues related to history taking, clinical examination and additional investigative tools for evaluation of the severity of sinonasal disease into a consensus document. A panel of European experts in the field of Rhinology has contributed to this consensus document on Diagnostic Tools in Rhinology.

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.

Effect of topical vapocoolant spray on skin test wheal, flare, and pain responses

BACKGROUND

Skin puncture and intradermal tests are commonly used to evaluate allergic rhinitis. Ethyl chloride, a topical vapocoolant spray, provides skin analgesia before venipuncture, but it has not been studied with allergy skin testing.

OBJECTIVE

To determine the effects of ethyl chloride vs placebo on skin puncture testing (SPT) and intradermal allergy testing.

METHODS

We enrolled 20 healthy adults with a history of positive aeroallergen skin test results in a randomized, double-masked, placebo-controlled study. Ethyl chloride and placebo sprays were randomly placed on the upper back. Paired SPT was performed with saline, histamine, and standardized aeroallergens, including Bermuda grass, Kentucky blue grass, timothy grass, cat, Dermatophagoides pteronyssinus, and Dermatophagoides farinae. Serial dilutional end-point intradermal tests were then performed using 1 standardized aeroallergen. Wheal and flare areas were outlined, scanned, and digitally measured. Participants used a 10-cm visual analog scale to record pain during skin testing.

RESULTS

Eighteen individuals completed the study. Compared with placebo, ethyl chloride had no significant effect on histamine wheal (P = .53), histamine flare (P = .39), aeroallergen wheal (P = .10), or aeroallergen flare (P = .71) area for SPT. Serial dilutional end-point intradermal testing was similar after ethyl chloride and placebo application (P = .75). Mean pain scores for SPT were improved with ethyl chloride compared with paired placebo skin tests, although pain scores did not reach significance for SPT (P = .21) or intradermal testing (P = .87).

CONCLUSIONS

Ethyl chloride does not significantly reduce histamine and aeroallergen wheal and flare areas during SPT and intradermal allergy skin testing. Ethyl chloride, vs placebo, reduced pain in some individuals during skin testing, although this did not attain statistical significance.

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.

Comparison of ipratropium bromide 0.03% with beclomethasone dipropionate in the treatment of perennial rhinitis in children

OBJECTIVE

To compare the safety and efficacy of ipratropium bromide 0.03% (IB) with beclomethasone dipropionate 0.042% (BDP) in the treatment of perennial rhinitis in children.

METHODS

Thirty-three children with nonallergic perennial rhinitis (NAPR) and 113 with allergic perennial rhinitis (APR) were randomly assigned to either IB or BDP for 6 months in a single-blind, multicenter protocol in which the physician was blinded to treatment. At each visit, patients and physicians rated symptom control of rhinorrhea, nasal congestion, and sneezing. Patients also completed quality of life questionnaires at baseline and after 6 months of therapy.

RESULTS

Both treatments showed a significant improvement in control of rhinorrhea, congestion, and sneezing compared with baseline over the 6 months of treatment (P < .05). Only for the control of sneezing was BDP consistently better than IB (P < .05). Among the patients given IB, 61% to 73% assessed the control of rhinorrhea as good or excellent on different study visit days, 43% to 60% similarly rated the control of nasal congestion, and 39% to 43% the control of sneezing. The results for BDP were 68% to 78% for the control of rhinorrhea, 55% to 72% for the control of nasal congestion, and 54% to 68% for the control of sneezing. Quality of life assessment documented that both drugs significantly reduced interference with daily activities and disturbance of mood due to rhinorrhea compared with baseline (P < .05). Both treatments were well tolerated with IB causing less nasal bleeding and irritation than BDP.

CONCLUSIONS

Ipratropium bromide was safe and effective in controlling rhinorrhea and diminishing the interference by rhinorrhea in school attendance, concentration on school work, and sleep. Ipratropium bromide was as effective as BDP in the control of rhinorrhea and showed a relatively good effect on congestion. Patient and physician assessment favored BDP in the control of sneezing.

Prevalence of sensitization to aeroallergens in California patients with respiratory allergy. Allergy Skin Test Project Team

BACKGROUND

The number of allergy skin tests required to evaluate patients with respiratory allergy has recently been challenged by the managed care community.

OBJECTIVES

The purpose of this study was to determine which aeroallergens are prevalent in patients with respiratory allergy (allergic rhinitis and bronchial asthma) in California.

METHODS

Utilizing aeroallergens thought to be relevant from recent aerobiologic and botanic data, 141 allergic and 17 asymptomatic control subjects were tested for the prevalence of 103 allergens. A standardized prick puncture technique and standardized interpretation of wheal/flare responses were utilized using the same lot of allergen for 13 allergy practices distributed throughout California. Frequency curves based on prevalence were established to determine the number of tests required to give up to 90% of positive responses for tree, weed and grass pollen, mold spores, and miscellaneous allergens which included house dust mite, cat, dog, and cockroach allergens.

RESULTS

Positive responses in allergic subjects for grasses ranged from 46% to 54%, for weeds 19% to 37%, and for trees 10% to 42%. For molds the range was from 11% to 22%. The response rate for Dermatophagoides pteronyssinus was 53%, for Dermatophagoides farinae 42%, for cat pelt 39% and cat hair 37%, for cockroach 23% and dog dander 19%. Asymptomatic control subjects responded to only 4% of all allergens tested. Ninety percent of all positive tests required three miscellaneous allergens (house dust mite, cat, and cockroach), 9 molds, 2 grasses, 16 weeds, and 27 trees for a total of 57 allergens (56% of total tested). There was no clear relationship between locale and specific allergen response, probably related to the limited number of subjects tested and variability within the same geographic region. Several seldom tested tree and weed allergens showed a higher prevalence rate than several commonly tested for allergens.

CONCLUSIONS

This preliminary study suggests that approximately 57 aeroalleroens might be adequate to detect 90% of all positive responses in patients with respiratory allergy in California. This study was limited by subject number and variability between study sites. It is hoped a standardized model can be developed from this pilot study to definitively determine which aeroallergens are relevant in the United States.

Reproducibility of skin prick test results in epidemiologic studies: a comparison of two devices

The reproducibility of skin prick tests under field conditions is essential for comparing prevalences between centers in epidemiologic multicenter studies. This study aimed to evaluate and compare the reproducibility of two widely used skin prick test devices: the Multi-Test and the ALK lancet. The subjects were 28 children, aged 6-14 years, with known sensitivities to Dermatophagoides pteronyssinus (D. pter.). Both devices were applied to each subject on two occasions, 1 week apart, by different, randomly assigned fieldworkers, using histamine, negative control, and the D. pter. allergen extract. For all three tested solutions, mean wheal sizes were larger for the Multi-Test than for the ALK lancet. The coefficient of variation for histamine was 21.8% for the Multi-Test and 17.3% for the ALK lancet. The coefficients of variation for the allergen D. pter. amounted to 47.4% for the Multi-Test and to 24.6% for the ALK lancet. The percentage of concordant test results was 92.6% for the Multi-Test and 100.0% for the ALK lancet for a cutoff point of wheal size equal to or greater than 1 mm. The results of this study suggest that the single ALK lancet performs slightly better than the Multi-Test device with respect to reproducibility under conditions of epidemiologic field studies.

Ipratropium nasal spray in children with perennial rhinitis

OBJECTIVE

To compare the efficacy and safety of ipratropium nasal spray and placebo administered twice each day for 4 weeks in pediatric patients with perennial rhinitis who had rhinorrhea as a major complaint.

METHODS

This was a multicenter, double-blind, parallel group study. Patients aged 6 to 18 years with symptoms of perennial nonallergic (PNAR) or perennial allergic rhinitis (PAR) were randomized to receive ipratropium (42 micrograms per nostril) or placebo nasal spray, double-blind, twice each day for 4 weeks. Efficacy was evaluated by nasal symptoms, especially anterior rhinorrhea, and quality of life. Previous caregivers for rhinitis and medications used in the past were also evaluated.

RESULTS

A total of 202 patients were empanelled, 162 with PAR, 40 with PNAR; of these 151 with mild-severe rhinorrhea were evaluated for efficacy. Treatment with ipratropium reduced symptoms of rhinorrhea primarily in patients with PNAR. In patients with PAR this response was less pronounced, and was seen as a modest decrease in the severity of rhinorrhea noted in the first 2 weeks of treatment. Quality of life assessments confirmed that rhinorrhea was bothersome to these pediatric patients, and suggested that treatment with ipratropium nasal spray was associated with an improvement, especially in the patients with PNAR. There were few adverse events; these were similar in the two treatment groups.

CONCLUSIONS

Ipratropium nasal spray 0.03% administered at a dose of 42 micrograms/nostril bid is a safe and effective new therapy for control of anterior rhinorrhea in pediatric patients with PNAR. Twice daily administration is adequate for patients with PNAR, but patients with PAR might benefit from more frequent administration (e.g., tid).

Comparison of two disposable plastic skin test devices with the bifurcated needle for epicutaneous allergy testing

BACKGROUND

The Greer DermaPIK and the Lincoln Diagnostics Duotip-Test are frequently used plastic, disposable, allergy skin testing devices.

OBJECTIVES

To compare the prick method of using the bifurcated needle and DermaPIK with the Duotip-Test using both the scratch (rotation) and prick methods for sensitivity, precision, and level of discomfort.

METHODS

Skin-testing was done with histamine and saline on the back in triplicate on 24 volunteers (mean age 32.8, seven males). Wheal and erythema were measured and a photograph was taken. Discomfort was rated on an analog scale.

RESULTS

The bifurcated needle and the Duotip-Test prick technique had significantly smaller histamine wheal and erythema responses than either the DermaPIK prick or Duotip-Test scratch techniques (P < .05). The Duotip-Test scratch produced significantly larger wheals (mean 1.1 mm, P < .001) to saline than the other three methods. Erythema to saline by Duotip-Test scratch (mean 3.16 mm) was significantly larger than the bifurcated needle (mean 1.2 mm, P < .001) and Duotip-Test prick method (mean 1.6 mm, P < .01). There was no statistical difference in the histamine coefficient of variation among the four methods. The Duotip-Test scratch method was rated significantly higher in patient discomfort (mean 21.6, P < .05) than the bifurcated needle (mean 7.8). No differences in discomfort were noted between the other methods.

CONCLUSIONS

The Duotip-Test scratch method had the largest mean wheal/erythema to histamine and the lowest CV. It had the most dermatographism and was more uncomfortable than the other methods. The other devices and methods were very similar in response to histamine and saline, and to precision and discomfort.