Provocation testing in polymorphic light eruption using fluorescent ultraviolet (UV) A and UVB lamps

BACKGROUND

Provocation testing is frequently performed during investigation of patients with suspected polymorphic light eruption (PLE). Techniques are not standardized between centres.

OBJECTIVES

We sought to evaluate the efficacy of different fluorescent ultraviolet (UV) radiation lamps for provocation testing in PLE.

METHODS

We analysed results in 68 patients referred consecutively for phototesting in whom a diagnosis of PLE seemed likely based on clinical history. Patients' case notes were reviewed and responses recorded to provocation testing on forearm skin over three consecutive days using broadband UVA, narrowband and broadband UVB lamps.

RESULTS

A positive papular response to broadband UVA exposure was seen in 38 patients [56%, estimated 95% population confidence interval (CI) 43-67.9]. Thirty-four patients (50%) had a positive papular response to narrowband UVB exposure (95% CI 37.6-62.4). The probability of a positive provocation test following irradiation with both lamps was 80.9% (95% CI 69.5-89.4). From April 1999, 34 patients also had provocation testing with broadband UVB. Although six patients (18%) had a positive papular response, they all showed a positive response to one or both of the other lamp types.

CONCLUSIONS

Provocation testing with fluorescent UVA and UVB lamps is a cheap and readily available method that can be used as a diagnostic aid to investigate patients with suspected PLE. Using both broadband UVA and narrowband UVB lamps for testing increases the likelihood of confirming the diagnosis than if either lamp is used alone.

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.

The results of skin prick testing in patients with allergic rhinitis: a comparison between a multiple lancet device and a single lancet

Skin prick testing (SPT) is widely used in the assessment of allergic disorders. Different SPT techniques are widely used. The aim of this study was to compare the response to SPT using a multiple lancet device (MLD) with the results of a single lancet (SL). Fifty patients with allergic rhinitis were included in this study. Initially, SPT was performed by a SL technique. After one week SPT was repeated using the MLD on all patients. The patients were tested with a panel containing 19 specific allergens including grass pollen, tree pollen, house dust mites, weed pollen allergen extracts, histamine and a negative control. The skin responses were recorded after 15 minutes for each device by measuring the diameter of the wheal and the erythema. The skin wheal responses for grass pollen, tree pollen, weed pollen and house dust mite allergen extracts obtained using the SL were generally significantly larger than those using the MLD. The comparison between the MLD and the SL methods revealed that SPT was positive with SL and negative with MLD in 176 tests (15.3%), and on the contrary SPT was positive with MLD and negative with SL in only 13 tests (1%). In conclusion, we claim that SPT using SL shows a higher degree of sensitivity and reproducibility.

Can we evaluate electrodermal testing?

Electrodermal testing (ED testing) is an acupuncture-based approach and was developed to refine homeopathic prescriptions. It is currently being used to advise patients about their "allergies". The evidence for its use in "allergy testing" is limited and often misrepresented. This article addresses the research and clinical issues involved in investigating the reliability and validity of various ED testing machines.

[The PIPET or Patient Individual Plate Easy Test]

The fresh outbreak of allergies and especially that increasingly early for food or even for new pneumallergens (sensitization already in utero) pushes us to test increasingly various and many allergens in children. The insufficiency of compliance of certain children to allergic skin tests encouraged us to seek new diagnostic methods. In our office we developed a new method of diagnosis by multipuncture, individualized and easily adaptable to each child. It is about a fast and reproductible prick-test which avoids stains and smudges due to the application of drops directly on the skin. It makes it possible to initially place easily all the tests on a plate (PIPET or Patient Individual Plate Easy Test) then on the skin by a multipuncture method. The tests can even already be prepared in the days which precede, provided that the plates are put in the fridge, with the name of the patient and the allergens used, for memory. It is about a rigorous test, reliable and careful, easy to carry out even in the most difficult children.

A comparison of two skin test methodologies and allergens from two different manufacturers

BACKGROUND

Skin prick tests (SPTs) are a frequently used method for evaluation of atopy. A variety of standard allergen preparations are available, together with a number of different methods of application.

OBJECTIVE

The objective of this study was to compare SPT reactivity 1) using Soluprick SQ allergens (ALK Allergologisk Laboratorium A/S, Hørsholm, Denmark) and Bayer allergens [Bayer Corporation, West Haven, CT], and 2) using two common methods of application, a standard prick lancet and a Quintest, both produced by Bayer.

METHODS

SPTs were undertaken on 22 adult volunteers (mean age 40 years, 17 female, 5 male). Wheal size was recorded as mean diameters (mm) and area (mm2).

RESULTS

Bayer allergens produced larger mean diameters and areas to dust mites than ALK allergens, with the differences significant when allergens were applied with the lancet. There was a tendency for the ALK cat allergen to produce larger reactions than the Bayer product. The method of application also influenced the wheal size, with the lancet producing significantly larger mean diameters than the Quintest for the histamine and allergens from both manufacturers, except the ALK cat allergen. There were similar differences between methods of application for reactions measured as an area.

CONCLUSIONS

SPTs that use different allergens or different methods of application will not provide comparable assessments of atopy.

Murine auricular transepidermal water loss -- a novel approach for evaluating irritant skin reaction in mice

The standard method for evaluating contact allergy in mice is the ear swelling technique. However, in experimental irritant contact dermatitis, the epidermal barrier disruption, that represents a predominant effect of irritants, cannot be assayed by this

METHOD

An appropriate method to evaluate barrier disruption is the measurement of transepidermal water loss (TEWL) but to date this has so far been possible only on the trunk of hairless or shaved mice. We therefore developed a new technique to measure the TEWL of mice ears (murine auricular TEWL: MATEWL). After patch testing with irritants and allergens, respectively, we found that the ear swelling method is most suitable for evaluating allergic skin reactions, whereas MATEWL is most appropriate for evaluating irritant skin reactions.

Is electrodermal testing as effective as skin prick tests for diagnosing allergies? A double blind, randomised block design study

OBJECTIVE

To evaluate whether electrodermal testing for environmental allergies can distinguish between volunteers who had previously reacted positively on skin prick tests for allergy to house dust mite or cat dander and volunteers who had reacted negatively to both allergens.

DESIGN

Double blind, randomised block design.

SETTING

A general practice in southern England.

PARTICIPANTS

15 volunteers who had a positive result and 15 volunteers who had a negative result on a previous skin prick test for allergy to house dust mite or cat dander.

INTERVENTION

Each participant was tested with 6 items by each of 3 operators of the Vegatest electrodermal testing device in 3 separate sessions (a total of 54 tests per participant). For each participant the 54 items comprised 18 samples each of house dust mite, cat dander, and distilled water, though these were randomly allocated among the operators in each session. A research nurse sat with the participant and operator in all sessions to ensure blinding and adherence to the protocol and to record the outcome of each test.

OUTCOME

The presence or absence of an allergy according to the standard protocol for electrodermal testing.

RESULTS

All the non-atopic participants completed all 3 testing sessions (810 individual tests); 774 (95.5%) of the individual tests conducted on the atopic participants complied with the testing protocol. The results of the electrodermal tests did not correlate with those of the skin prick tests. Electrodermal testing could not distinguish between atopic and non-atopic participants. No operator of the Vegatest device was better than any other, and no single participant's atopic status was consistently correctly diagnosed.

CONCLUSION

Electrodermal testing cannot be used to diagnose environmental allergies.

Evaluation of three methods for using the Duotip-Test device for skin testing

The sensitivity and precision of rotation, prick and puncture methods of using the Duotip-Test for epicutaneous allergy skin testing were evaluated. Forty-one volunteers who had not taken any antihistamines within the previous two weeks were recruited. The mean age was 21.6 years (range 18 to 25 years). Histamine hydrochloride 1 mg/ml and 50% glycerol saline were used as positive and negative controls, respectively. Each method of testing was performed in triplicate on the volar surface of both forearms. Wheal and flare were measured 15 minutes later. Rotation, prick and puncture methods produced histamine mean wheal diameter +/- standard deviation of 6.61 +/- 0.87 mm, 3.86 +/- 1.03 mm, and 3.00 +/- 0.65 mm, respectively (p < 0.01). The coefficient of variation of rotation method was 13.13%. It was the only method that gave coefficient of variation lower than 20%. False negative and false positive proportions of rotation method using a 4 mm criterion for positive reaction were 1.5% and 0.75%, respectively. Rotation method was well accepted by the volunteers although it was ranked highest in pain. We concluded that the rotation method of using Duotip-Test is a highly reliable technique for skin testing.

A blinded, multi-center evaluation of two commercial in vitro tests for latex-specific IgE antibodies

PURPOSE

To compare the diagnostic value of two commercial in vitro tests for the detection of latex-specific IgE antibodies.

METHODS

Serum samples were collected from latex-allergic and nonlatex-allergic individuals. Persons were classified as latex allergic if they had a positive clinical history and a positive skin prick test with a latex extract. Persons with no latex-related symptoms and negative skin tests were classified as nonlatex allergic. The serum samples were tested in a blinded fashion by a laboratory using the CAP (Pharmacia-Upjohn) and AlaSTAT (Diagnostic Products Company) assays. Values of 0.35 kA U/L or greater were considered positive in both tests.

RESULTS

The 143 sera studied came from 83-latex allergic and 60 nonallergic persons. The in vitro tests were found to have sensitivities of 79.5% and 73.8%, and specificities of 90.2% and 91.7%, for CAP and AlaSTAT, respectively. The positive predictive values were 91.7% and 92.5%, while the negative predictive values were 76.4% and 71.4% for the CAP and AlaSTAT, respectively.

CONCLUSION

In individuals classified by the combination of clinical history and skin test results, both the Pharmacia CAP and the DPC AlaSTAT demonstrated acceptable sensitivities, specificities, and predictive values for detection of antilatex IgE antibodies. These findings suggest that both assays can be useful adjuncts to the diagnosis of latex allergy.

Comparison of the Quintest to the lancet in allergic skin testing

Many skin testing devices have been commercially available over recent years, but use has been limited because of significantly greater costs of such devices. Therefore, the lancet continues to be the most widely used skin testing device in Australia. This study compared performance of another multitest device, the Bayer Quintest to the Becton Dickinson Microlance. Nineteen atopic volunteers were skin tested using histamine dihydrochloride 10 mg/ml, glycerosaline and eight allergens. In 190 tests, 6 discrepancies between the Quintest and Microlance occurred. The Microlance produced slightly larger wheals than the Quintest, reaching statistical significance in 3 allergens. We found the Quintest comparable to the Microlance in concordance of positive and negative allergen responses and in wheal size. The Quintest had higher acceptability to both participants and staff for comfort, ease of use and safety. The Quintest's major advantage is the ability to rapidly screen large numbers of subjects, especially during clinical trials. The major limitation is it's cost.

[A new device for allergen skin testing]

We have made a new device for allergen skin testing, which can be used easily. It consists of two parts. One, several gears are fixed on a board in a row, and when one gear goes round, other gears also go round simultaneously. A disposable needle is attached to each gear. A semi-spherical hole is made in the lower surface of a disposable needle, and a sharp needle is fixed in, but not at the centre of the hole. The other, small tanks are arranged in a row at the same distance as the gears. When the disposable needles are inserted to the tanks filled with allergen extract, it is hold in a semi-spherical hole by surface tension. The allergen extracts go intradermally, when the needles move semi-circular on a human skin. We performed skin tests to 23 patients with this device, and got satisfactory results as screening tests.

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.

Evaluation of devices for skin prick testing

BACKGROUND

Previous comparisons of devices for percutaneous skin testing have revealed statistically and clinically significant differences, from one device to another, in the size of reactions to histamine and allergen extracts and at negative control sites.

OBJECTIVE

The objective of this study was to compare the performance of several skin test devices which are either new, modified, or used with a modified technique.

METHODS

Twenty subjects were tested five to eight times with each of the devices both to glycerol-saline and to 10 mg/ml histamine base. The devices tested were the MultiTest II, Duo Tip-Test (prick and scarification), Quintest, DermaPik (prick and scarification), and small pox needle.

RESULTS

There were highly significant differences among the devices for the size of the reaction to histamine (mean wheal diameter 4.28 to 8.59 mm, p < 0.0001), the standard errors of the wheals to histamine (0.82 to 1.45 mm, p < 0.05) and in the mean wheal size with glycerol-saline (0.00 to 2.48 mm, p < 0.0001).

CONCLUSIONS

Devices for performing skin prick testing vary greatly in several characteristics, including the size of reactions at both positive and negative test sites. Each skin test technician should be tested with the device used in that skin testing laboratory to establish criteria for positive and negative tests.

Solar urticaria. A report of 25 cases and difficulties in phototesting

BACKGROUND

Solar urticaria is a rare photosensitive disease, and its differential diagnosis with respect to polymorphous light eruption is sometimes difficult. We report our experience with 25 cases of solar urticaria and discuss the pitfalls in phototesting such patients.

OBSERVATION

The most important locations in this patient series are the V of the neck and the arms, which are similar to those of polymorphous light eruption. In all of the patients, however, the lesions appeared within 30 minutes of sun exposure or phototesting and disappeared within 24 hours. Notably, 12 (48%) of the patients had a history of atopy. Phototesting helps confirm the diagnosis, but, in some patients, this was difficult.

CONCLUSIONS

A negative phototest result from a single light source does not necessarily exclude a diagnosis of solar urticaria. In patients in whom phototesting elicits negative reactions, other light sources should be used, and, if the phototest result is still negative, a provocative test with natural sunlight should be done. Histamine1-receptor antihistamines are a useful first-line therapy, although more severely affected persons may require prophylactic courses of phototherapy or photochemotherapy. The main problem is maintenance treatment.

Electrical impedance for quantification and classification of experimental skin reactions

BACKGROUND

Pathophysiologic events in biological tissue are characterized by a shift of the electrical impedance spectra of the tissue under study.

OBJECTIVE

To discuss studies on experimental skin reactions with an improved impedance spectrometer. The instrumentation is related to noninvasive techniques based on other physical principles.

METHODS

The results from studies on patients with allergic contact reactions (n = 8), prick tests (n = 10), and irritant contact reactions (benzalkonium chloride [n = 14], sodium lauryl sulfate [n = 12], and nonanoic acid [n = 14]), and an appropriate number of controls are reviewed.

RESULTS

Results show statistically significant changes of the impedance parameters when compared with relevant controls, at different types of experimental cutaneous reactions, both allergic and irritant type. Each reaction type had a specific impedance index pattern.

CONCLUSIONS

Current data indicate that the improved impedance technique offers a possible noninvasive alternative for characterization and perhaps differentiation, not only between the skin responses induced by either an allergen or an irritant, but also a capability to distinguish responses induced by chemically different irritants. The assumption that the impedance method is capable to distinguish allergic from irritant contact reactions has not been proven yet in direct comparative studies.

Bevel-down superior to bevel-up in intradermal skin testing

BACKGROUND

Intradermal skin testing is one of the most widely used procedures in the diagnosis of hypersensitivity diseases in vivo. It is critical to perform the test accurately and expediently. Yet, there are few articles describing its detailed technique or proficiency available.

OBJECTIVES

To identify the better method for intradermal testing between the bevel-up and bevel-down techniques.

METHODS

Three inexperienced testers performed intradermal injections using both methods. Four sets of paired trails each consisting of ten injections were applied randomly, alternating between the same volunteer subject's contralateral arms. Duration to complete ten injections was measured. Numbers of injection sites that bled, that squirted into the air, and failed to form a bleb were counted. The overall comfort level was determined.

RESULTS

The time to complete the injections by bevel-up and by bevel-down methods were 165.5 +/- 31.3 and 152.5 +/- 27.4 seconds, respectively (P < .015). The number of injection sites that bled was higher in the bevel-up method, particularily on trial one (P < .001). Completion rate of successful bleb formation in bevel-down was 27.3 as compared with 23.3 in bevel-up method (P = .013). The comfort level was higher with the bevel-down than the bevel-up method (P = .0001).

CONCLUSION

The bevel-down method of intradermal testing is superior to the bevel-up method.