A comparison of multiheaded devices for allergy skin testing

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.

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.

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.

The skin prick test - European standards

Skin prick testing is an essential test procedure to confirm sensitization in IgE-mediated allergic disease in subjects with rhinoconjunctivitis, asthma, urticaria, anapylaxis, atopic eczema and food and drug allergy. This manuscript reviews the available evidence including Medline and Embase searches, abstracts of international allergy meetings and position papers from the world allergy literature. The recommended method of prick testing includes the appropriate use of specific allergen extracts, positive and negative controls, interpretation of the tests after 15 – 20 minutes of application, with a positive result defined as a wheal ≥3 mm diameter. A standard prick test panel for Europe for inhalants is proposed and includes hazel (Corylus avellana), alder (Alnus incana), birch (Betula alba), plane (Platanus vulgaris), cypress (Cupressus sempervirens), grass mix (Poa pratensis, Dactilis glomerata, Lolium perenne, Phleum pratense, Festuca pratensis, Helictotrichon pretense), Olive (Olea europaea), mugwort (Artemisia vulgaris), ragweed (Ambrosia artemisiifolia), Alternaria alternata (tenuis), Cladosporium herbarum, Aspergillus fumigatus, Parietaria, cat, dog, Dermatophagoides pteronyssinus, Dermatophagoides farinae, and cockroach (Blatella germanica). Standardization of the skin test procedures and standard panels for different geographic locations are encouraged worldwide to permit better comparisons for diagnostic, clinical and research purposes.

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.

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.

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.

High prevalence of skin test positivity in severe or difficult-to-treat asthma

BACKGROUND

Skin tests are considered the gold standard for detecting allergen-specific immunoglobulin E (IgE) in the clinical setting and are an important tool for diagnosing and managing allergic asthma.

OBJECTIVE

To assess the prevalence of skin testing in patients > or = 12 years enrolled in The Epidemiology and Natural History of Asthma: Outcomes and Treatment Regimens (TENOR) study.

METHODS

Patients were asked whether they had ever been skin tested and, if so, they were asked to provide the test results. Clinical characteristics were used to compare positive (ST+), negative (ST-), and skin test not done (STND) patients.

RESULTS

Of 2,985 patients eligible, 85.8% recalled being skin tested. Of those tested, 93.5% were positive (allergist 95.7%, pulmonologist 87.3%). A high proportion of Whites (93.5%) and non-Whites (94.0%) were ST+; however, more non-Whites had never been skin tested (21.7% vs. 12.3%, respectively; p < 0.0001). Total serum IgE was 104.6 IU/mL for ST+ patients, 87.1 IU/mL for STND patients, and 32.4 IU/mL for ST- patients. Age at asthma onset, duration of asthma, and the prevalence of atopic disorders and asthma triggers differentiated the ST+ from the ST- group. Disease severity appeared similar between the two groups. In general, values for STND patients were closer to the ST+ group, suggesting that those not tested would have been ST+ if administered a test.

CONCLUSIONS

The prevalence of ST+ patients was high in allergy and pulmonology practices, and in White and non-White patients. These data support the utility of a more complete allergic evaluation in severe asthmatics. Skin testing appears associated with disease pathophysiologies in asthma.

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.

Advances in upper airway diseases and allergen immunotherapy

Evidence of an increased prevalence of rhinitis in patients with asthma, and asthma in patients with rhinitis, supports the 1 airway concept. However, there are basic differences between the upper and lower airways, such as the virtual absence of remodeling in the nose compared with the bronchi, despite the presence of similar inflammation. Etiologic factors in chronic rhinosinusitis (CRS) attract increasing interest. Peripheral blood monocytes from patients with CRS release IL-4, IL-13, and IFN-gamma on stimulation with fungal antigens, especially those from Alternaria. This is not seen with cells from normal controls. However, a double-blind trial of intranasal amphotericin in CRS was negative. Evidence continues to accumulate of the pivotal role of regulatory T-lymphocytes secretion of IL-10 in the response to allergen immunotherapy. In patients with asthma and house dust mite allergy who are receiving appropriate pharmacotherapy and have instituted environmental controls, house dust mite immunotherapy provides marginal additional benefits in asthma control. Immunotherapy with cat dander extract at a maintenance dose containing 15 microg Fel d 1 produces a more consistent immunologic response than with maintenance doses containing 3.0 microg, whereas doses containing only 0.6 microg are no more effective than placebo. Sublingual immunotherapy for seasonal grass allergy can be safely administered by general practitioners, but symptom relief begins only in the second season of therapy. Sublingual immunotherapy for seasonal grass allergy in children reduced symptoms and onset of new asthma symptoms but, again, beginning only in the second year of treatment. A course of 6 weekly injections of ragweed Amb a 1 bound to cytosine phosphorothionate guanosine containing DNA produced a shift from T H 2 to T H 1 cytokine release both in peripheral blood cells and in the nose after allergen challenge. No symptom improvement was seen the first year, but symptoms were reduced the second year without further treatment.