Patch testing with aluminium Finn Chambers could give false-positive reactions in patients with contact allergy to aluminium.

BACKGROUND: Earlier laboratory studies have shown that sodium tetrachloropalladate, Myroxylon pereirae, caine mix II, and palladium chloride trigger the release of aluminium (Al) from Finn Chambers (FC). OBJECTIVES: To investigate whether aluminium realease from FC could influence the diagnostic outcome of patch testing with FC. METHOD: A retrospective analysis of patch test results from 2010 to 2019 was performed. A two-sided Fisher's exact test was used to calculate any overrepresentation of contact allergy to Al among patients with positive reactions to sodium tetrachloropalladate, Myroxylon pereirae, caine mix II, and palladium chloride. RESULTS: A total of 5446 patients had been tested with FC during the study period. There was a significant overrepresentation of contact allergy to Al among patients with positive reactions to sodium tetrachloropalladate, Myroxylon pereirae, caine mix II, and palladium chloride. Patients with a strong Al allergy had significantly higher amounts of concomitant reactions to sodium tetrachloropalladate, Myroxylon pereirae, caine mix II, and palladium chloride compared to patients with weak Al allergy. These results were not seen for patients tested with Finn Chambers AQUA. CONCLUSION: In patients with contact allergy to Al, patch testing with Finn chambers could give false-positive reactions to sodium tetrachloropalladate, Myroxylon pereirae, caine mix II, and palladium chloride.

A Novel Device that Reduces Preparation Times and Precision Mass Error in Patch Testing for Allergic Contact Dermatitis.

BACKGROUND: Patch test preparation for evaluation of allergic contact dermatitis is traditionally a slow process with inherent errors. OBJECTIVE: A novel device, referred to as a syringer, designed to dispense 10 unique petroleum-based haptens simultaneously, significantly reduces preparation time and increases the precision of the mass dispensed per well. METHODS: The syringer was custom designed and "printed" through the use of a 3-dimensional printer with a polylactic acid plastic medium. RESULTS: The syringer dispensed 10 haptens significantly (P < 0.05) faster: 6.9 seconds on average, compared with 29.6 seconds by the traditional method. The syringer demonstrated a significantly (P < 0.05) lower average deviation of each strip's per-well mass average compared with the traditional method. CONCLUSIONS: In practice, this syringer is ideal for preparing patient-ready patch tests in quantities of 2 identical strips or more.

Optoacoustic mesoscopy shows potential to increase accuracy of allergy patch testing.

BACKGROUND: Differentiation between irritant and allergic skin reactions in epicutaneous patch testing is based largely on subjective clinical criteria, with the risk of high intraobserver and interobserver variability. Novel dermatological imaging using optoacoustic mesoscopy allows quantitative three-dimensional assessment of microvascular biomarkers. OBJECTIVES: We investigated the potential of optoacoustic imaging to improve the precision of patch test evaluation. METHODS: Sixty-nine test reactions and 48 healthy skin sections in 52 patients with suspected type IV allergy were examined using raster-scan optoacoustic mesoscopy. RESULTS: We identified biomarkers from the optoacoustic images. Allergic reactions were associated with higher fragmentation of skin vasculature than irritant reactions (19.5 ± 9.7 vs 14.3 ± 3.7 fragments/100 pixels2 ; P < .05), as well as lower ratio of low- to high-frequency acoustic signals (1.6 ± 0.5 vs 2.0 ± 0.6, P < .05). Allergic reactions graded "++" showed higher vessel fragmentation than reactions graded "+" (25.4 ± 13.2 vs 17.1 ± 6.5 fragments/100 pixels2 ; P < .05). A linear model combining the biomarkers fragmentation and frequency ratio could differentiate allergic from irritant test reactions with an area under the receiving operator characteristic curve of 0.80 (95% confidence interval 0.64-0.91), reaching a sensitivity of 81% and specificity of 63%. CONCLUSIONS: Optoacoustic mesoscopy shows potential to help in differentiating between allergic and irritant test reactions based on novel biomarkers that may reflect vasodilation, vessel tortuosity, and edema.

Thoughts on how to improve the quality of multicentre patch test studies.

Multicentre patch test studies (MPTSs) can contribute useful information for diagnostic and preventive measures. The aim of the present paper is to propose how to perform high-quality MPTSs. To this end, factors of significance for the patch test result are discussed with regard to the standardization and calibration of high-quality MPTSs. The 16 factors discussed are scored 0, 1, 2, or 3, depending on the relative importance of a particular factor for the patch test result. The total score of an MPTS allows it to be ranked as having doubtful, acceptable, high or excellent quality. A total score of 30 is possible. Depending on the total score the MPTSs are grouped into those with a doubtful, acceptable, high, and excellent quality. In conclusion, high-quality MPTSs can be performed and are facilitated if a guideline and check list are followed when the study is being planned. The scoring enables the calculation of a total score, which can be used for quality ranking.

[Should metal alloy discs be used for patch testing in suspected metal implant intolerance reaction?]. / DKG-Stellungnahme zur Epikutantestung von Metalllegierungsplättchen bei Verdacht auf Metallimplantat-Unverträglichkeit.

Intolerance reactions to metal implants may be caused by metal allergy. However, prior to implantation, patch testing should not be done in a prophylactic-prophetic approach. Pre-implant patch testing should only be performed to verify or exclude metal allergy in patients with a reported respective history. In the case of implant-in particular arthroplasty-related complications like, for example, pain, effusion, skin changes, reduced range of motion, or loosening, orthopedic-surgical differential diagnostics should be performed first. Allergological workup of suspected metal implant allergy should be done with the DKG baseline series which contains nickel-, cobalt- and chromium-preparations. Various studies assessing the usefulness of metal alloy discs for patch testing proved that this approach does not give reliable information about metal allergy. Positive patch test reactions to the discs cannot be assigned to a specific metal within the disc alloy components. Furthermore, availability of such metal discs might be an invitation to uncritical testing. Accordingly, due to lack of benefit in comparison to patch testing with standardized metal salt preparations, we do not recommend patch testing with metal alloy discs.

Novel metal allergy patch test using metal nanoballs.

BACKGROUND: Patch tests are often used in the clinical diagnosis of metal allergies. In currently available patch tests, high concentrations of metal salt solutions are used. However, diagnosis accuracy can be influenced not only by acute skin reactions to high concentrations of metal salt, but also by skin reactions to other components present in the patch or to pH changes. In this study, we developed Ni nanoparticles (termed "nanoballs") for use in patch-test solutions. FINDINGS: Highly soluble, spherical Ni nanoballs were prepared using plasma electrolysis. The Ni released from the nanoballs permeated through a dialysis membrane, and the nanoball-containing solution's pH was maintained constant. Ni ions were released slowly at low concentrations in a time-dependent manner, which contrasted the rapid release observed in the case of a commercial patch test. Consequently, in the new test system, reactions caused by high concentrations of metal salts were avoided. CONCLUSIONS: By exploiting the high specific surface area of Ni nanoballs, we obtained an effective dissolution of Ni ions that triggered Ni allergy in the absence of direct contact between the nanoballs and mouse skin. This novel patch system can be applied to other metals and alloys for diagnosing various types of metal-induced contact dermatitis.

Using a nonadherent transparent scribing sheet: tip for allergen location in pediatric contact dermatitis testing.

We discuss the use of a nonadherent transparent scribing sheet as a tool to aid in allergen location during patch testing in pediatric patients.

Patch tests / Testes de contato

Patch tests were introduced as a diagnostic tool in the late nineteenth century. Since then, they have improved considerably becoming what they are today. Patch tests are used in the diagnostic investigation of contact dermatitis worldwide. Batteries or series previously studied and standardized should be used in patch testing. The methodology is simple, but it requires adequate training for the results to be correctly interpreted and used. Despite having been used for over a century, it needs improvement like all other diagnostic techniques in the medical field.

Os testes de contato foram introduzidos, como ferramenta diagnóstica, no final do século XIX. Desde então passaram por diversos aprimoramentos tornando-os o que são hoje. Eles são utilizados na investigação diagnóstica das dermatites de contato em diferentes partes do mundo. Devem ser aplicados com a utilização de baterias ou séries previamente estudadas e padronizadas. A metodologia é simples, mas requer treinamento adequado para sua interpretação e bom aproveitamento dos resultados obtidos. Apesar de ser utilizado há mais de um século, necessita de aprimoramentos como todas as outras técnicas utilizadas para investigação diagnóstica na área médica.

Patch tests.

Patch tests were introduced as a diagnostic tool in the late nineteenth century. Since then, they have improved considerably becoming what they are today. Patch tests are used in the diagnostic investigation of contact dermatitis worldwide. Batteries or series previously studied and standardized should be used in patch testing. The methodology is simple, but it requires adequate training for the results to be correctly interpreted and used. Despite having been used for over a century, it needs improvement like all other diagnostic techniques in the medical field.

Stability of selected volatile contact allergens in different patch test chambers under different storage conditions.

BACKGROUND: Patch test preparations of volatile substances may evaporate during storage, thereby giving rise to reduced patch test concentrations. OBJECTIVES: To investigate the stability of selected acrylates/methacrylates and fragrance allergens in three different test chambers under different storage conditions. METHODS: Petrolatum samples of methyl methacrylate (MMA), 2-hydroxyethyl methacrylate (2-HEMA), 2-hydroxypropyl acrylate (2-HPA), cinnamal and eugenol in patch test concentrations were stored in three different test chambers (IQ chamber™, IQ Ultimate™, and Van der Bend® transport container) at room temperature and in a refrigerator. The samples were analysed in triplicate with high-performance liquid chromatography. RESULTS: The decrease in concentration was substantial for all five allergens under both storage conditions in IQ chamber™ and IQ Ultimate™, with the exception of 2-HEMA during storage in the refrigerator. For these two chamber systems, the contact allergen concentration dropped below the stability limit in the following order: MMA, cinnamal, 2-HPA, eugenol, and 2-HEMA. In the Van der Bend® transport container, the contact allergens exhibited acceptable stability under both storage conditions, whereas MMA and 2-HPA required cool storage for maintenance of the limit. CONCLUSION: The Van der Bend® transport container was the best device for storage of samples of volatile contact allergens.

Laboratory skinpatches and smart cards based on foils.

This paper presents: (i) a hand held system consisting of a portable platform and disposable polymeric Lab-on-a-card capable of performing a nucleic acid concentration, amplification and detection with reagents inside; and a (ii) wearable diagnostic Lab-on-a-Paper skinpatch system, capable of performing in-situ sweat sampling, analyte pre-concentration, and immunoassay analysis. The skinpatch works in conjunction with a hand-held optoelectronic reader / micro PC fluorescence analysis interface.