‘Calibration’ of our patch test reading technique is necessary

Allergic or Not: Final Interpretation of Doubtful Patch Test Reactions From the North American Contact Dermatitis Group, 2019-2020

Background: Doubtful patch test reactions generally do not meet criterion for positivity in patch testing. However, the North American Contact Dermatitis Group (NACDG) allows for doubtful reactions to be coded with a final determination of "allergic/positive" based on the temporal pattern, appearance, known characteristics of the allergen, and/or other supportive patch test reactions. Objectives: To analyze NACDG data from the 2019-2020 patch test cycle to identify patterns in the interpretation and relevance of doubtful reactions. Methods: The frequency and proportions of doubtful reactions were tabulated and analyzed for patterns. Statistical analyses were limited to allergens with ≥30 doubtful reactions to ensure adequate sample size. Results: Of patch-tested patients, 31.9% (1315/4121) had ≥1 doubtful reaction. Of 2538 total doubtful reactions, 46% (n = 1167) had a final interpretation of "allergic/positive." The allergens with the highest proportion of doubtful reactions at the final visit were hydroperoxides of linalool 1% (4.5%), fragrance mix I 8.0% (3.9%), and cetrimonium chloride 0.5% (3.4%). Methylchloroisothiazolinone/methylisothiazolinone (MCI/MI) 0.02% (P < 0.001), MI 0.2% (P < 0.001), nickel sulfate hexahydrate 2.5% (P = 0.001), and neomycin sulfate 20.0% (P = 0.003) doubtful reactions were more likely to be interpreted as allergic than nonallergic. Methyldibromoglutaronitrile/phenoxyethanol 0.2% (P < 0.001), oleamidopropyl dimethylamine 0.1% (P < 0.001), formaldehyde 2.0% (P < 0.001), cetrimonium chloride 0.5% (P < 0.001), benzophenone-4 (sulisobenzone) 10% (P < 0.001), iodopropynyl butylcarbamate 0.5% (P < 0.001), cocamidopropyl betaine 1.0% (P = 0.002), and benzisothiazolinone 0.1% (P = 0.012) doubtful reactions were less likely to be interpreted as allergic. Of the 1167 doubtful reactions interpreted as allergic, 84.9% had current relevance. Conclusions: Doubtful reactions were common and approximately one half were coded with a final interpretation of "allergic/positive." Of those, most were clinically relevant. MCI/MI, MI, nickel, and neomycin were more likely to be interpreted as allergic.

Contact Allergy to Shellac. Retrospective Cross-Sectional Study With Data From the Spanish Registry of Research in Contact Dermatitis and Cutaneous Allergy (REIDAC)

INTRODUCTION

Shellac is a known allergen present mainly in cosmetics used on the eyelids and lips, although new sources of exposure have recently been described. Our objective was to assess the use of shellac as a contact allergen in Spain and the clinical profile of patients allergic to shellac.

METHODS

This retrospective cross-sectional study included patients patch tested for shellac between 2018 and 2021 from the Spanish Registry of Contact Dermatitis and Cutaneous Allergy (REIDAC).

RESULTS

A total of 980 patients were patch tested for shellac (20% in ethanol), and 37 (3.77%, 95% confidence interval [CI], 2.58-3.97%) showed positive results. Most of these patients were tested for shellac due to a suspicion of cosmetic contact dermatitis. Seven patients with present relevance were found, five with relation to cosmetics, and the other two with an occupational background of food handling. The reaction index for shellac was 0.51 and the positivity ratio was 67.56% (95% CI, 52.48-82.65%).

CONCLUSIONS

Shellac appears to be a prevalent allergen in patients with suspected contact dermatitis related with cosmetics or foodstuff. However, further studies are needed to validate its use in other patients.

Epicutaneous Patch Testing in Type IV Allergy Diagnostics: State of the Art and Best Practice Recommendations

This chapter summarises all relevant aspects of patch testing, closely following recommendations outlined in a recent European, and a German S3 guideline on diagnostic patch testing with contact allergens and medicinal products (drugs). Patch testing is indicated in patients suspected of suffering, or having been suffering, from delayed-type hypersensitivity leading to allergic contact dermatitis or other skin and mucosal diseases. Sections of this chapter include detailed indications, reasons for possibly postponing the test, considerations on choosing haptens (contact allergens) to test, various aspects of the application of patch test allergen preparations (storage, dosing) and of testing with individual materials provided by the patients. Special aspects of patch testing in cutaneous adverse drug reactions, children, or occupational contact dermatitis are outlined. Supplemental test methods, notably the repeated open application test, are briefly described. Finally, the final evaluation in terms of assessment of clinical relevance of reactions and patient counselling are outlined.

Patch Testing with Propolis of Different Geographical Origins in a Baseline Series

The chemical composition of propolis varies with geographical origin; however, it is not known whether this affects the frequency of contact allergy to propolis. In order to study the frequency of contact allergy to propolis of different geographical origins and concomitant reactions, 1,470 consecutive patients with dermatitis from Denmark, Lithuania and Spain were patch tested with propolis from China, Lithuania, North America and Sweden, and with a baseline series. Patch test reactions to any type of propolis ranged from 1.3% to 5.8%. There were no statistically significant differences in the frequency of positive reactions between the 4 types of propolis in the respective countries. Testing with a single commercially available type of propolis detects only approximately half of propolis-allergic patients. In patients allergic to propolis, concomitant reactions to Myroxylon pereirae resin, colophonium and Fragrance mix I were common, ranging from 12.5% to 50.0%.

Contact allergy to haptens in the Swedish baseline series: Results from the Swedish Patch Test Register (2010 to 2017)

BACKGROUND

Allergic contact dermatitis has considerable public health impact and causative haptens vary over time.

OBJECTIVES

To report the prevalence of contact allergy to allergens in the Swedish baseline series 2010 to 2017, as registered in the Swedish Patch Test Register.

METHODS

Results and demographic information for patients tested with the Swedish baseline series in 2010 to 2017 were analysed.

RESULTS

Data for 21 663 individuals (females 69%) were included. Females had significantly more positive patch tests (54% vs 40%). The reaction prevalence rates were highest for nickel sulfate (20.7%), fragrance mix I (7.1%), Myroxylon pereirae (6.9%), potassium dichromate (6.9%), cobalt chloride (6.8%), methylchloroisothiazolinone/methylisothiazolinone (MCI/MI; 6.4%), MI (3.7%), colophonium (3.5%), fragrance mix II (3.2%), and formaldehyde (3.2%). Myroxylon pereirae reaction prevalence increased from 5% in 2010 to 9% in 2017 and that for methyldibromo glutaronitrile from 3.1% to 4.6%. MCI/MI and MI reactions decreased in prevalence after 2014. Nickel reaction prevalence decreased among females aged 10 to 19 years.

CONCLUSIONS

Nickel remains the most common sensitizing agent, with reaction prevalence decreasing among females younger than 20 years. The changes in MCI/MI and MI reaction prevalence mirrored those in Europe. The register can reveal changes in contact allergy prevalence over time among patients patch tested in Sweden.

Validation of questionnaire algorithm based on repeated open application testing with the constituents of fragrance mix II: the EDEN Fragrance Study

BACKGROUND

In a European study on contact allergy in the general population, it has been hypothesized that the combination of contact allergy to a fragrance together with a history indicating dermatitis at exposure and thereafter subsequent avoidance of scented products implied a diagnosis of allergic contact dermatitis.

OBJECTIVES

The primary aim of this study was to validate this hypothesis/algorithm. The secondary aim was to investigate whether there was any association between the outcome of the recent repeated open application test (ROAT) and the patch test reactivity.

METHODS

One hundred nine subjects with and without contact allergy to fragrance mix II (FM II) were recruited. Volunteers from six European dermatology clinics participated in the study including a patch test and a ROAT.

RESULTS

Twenty-four positive ROAT reactions were noted in total including 20 of those 32 with contact allergy to FM II. None of the volunteers reacted to the vehicle (P < 0.001). More individuals with a positive algorithm had positive ROATs when compared with those with a negative algorithm. However, the difference was not statistically significant (P = 0.12). The lower the patch test concentration eliciting a positive test reaction, the more likely was a positive ROAT and the more likely that the positive ROAT appeared early during the investigative period.

CONCLUSIONS

The algorithm used in this study was not validated but it was indicated in this ROAT setup. The stronger the patch test reactivity the more likely was a positive ROAT and the more likely it was that the positive ROAT appeared early during the application period.

Inter-rater variability in patch test readings and final interpretation using store-forward teledermatology

BACKGROUND

Data regarding teledermatology for patch testing are limited.

OBJECTIVES

Compare patch test readings and final interpretation by two in-person dermatologists (IPDs) with eight teledermatologists (TDs).

METHODS

Patch tested patients had photographs taken of 70 screening series of allergens at 48 hours and second readings. Eight TDs reviewed photos and graded reactions (negative, irritant, doubtful, +, ++, +++) at 48 hours and second readings; in addition, they coded a final interpretation (allergic, indeterminant, irritant, negative) for each reaction. TDs rated overall image quality and confidence level for each patient and patch test reaction, respectively. Percentage of TD-IPD agreement based on clinical significance (success, indeterminate, and failure) was calculated. Primary outcome was agreement at the second reading.

RESULTS

Data were available for 99, 101, and 66 participants at 48 hours, second reading, and final interpretation, respectively. Pooled failure (+/++/+++ vs negative) at second reading was 13.6% (range 7.9%-20.4%). Pooled failure at 48 hours and final interpretation was 5.4% (range 2.9%-6.8%) and 24.6% (range 10.2%-36.8%), respectively. Confidence in readings was statistically correlated with quality of images and disagreement.

CONCLUSION

For patch testing, teledermatology has significant limitations including clinically significant pooled failure percentages of 13.6% for second readings and 24.6% for final interpretation.

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.

Contact dermatitis associated with preservatives: Retrospective analysis of North American Contact Dermatitis Group data, 1994 through 2016

BACKGROUND

Preservatives are often necessary components of commercial products. Large-scale North American studies on preservative allergy are limited.

OBJECTIVE

To evaluate demographics, positive patch test reactions (PPTRs), clinical relevance, and trends for preservatives tested by the North American Contact Dermatitis Group.

METHODS

We conducted a retrospective cross-sectional analysis of North American Contact Dermatitis Group patch testing results of preservatives from 1994 through 2016.

RESULTS

A total of 50,799 patients were tested; 11,338 (22.3%) had a PPTR to at least 1 preservative. The most frequent reactions were to methylisothiazolinone 0.2% aqueous (aq) (12.2%), formaldehyde 2% aq (7.8%), formaldehyde 1% aq (7.8%), quaternium-15 2% petrolatum (pet) (7.7%), and methyldibromo glutaronitrile/phenoxyethanol 2% pet (5.1%). Paraben mix 12% pet (1%), iodopropynyl butylcarbamate 0.1% pet (0.4%), benzyl alcohol 1% pet (0.3%), and phenoxyethanol 1% pet (0.2%) had the lowest PPTRs. Linear regression analysis of preservatives tested showed that only methylchloroisothiazolinone/methylisothiazolinone 0.01% aq (parameter estimate, 0.42; 95% CI, 0.17-0.66; P < .005) had a significant increase in PPTRs over time.

LIMITATIONS

Collected variables are dependent on clinical judgment. Results may be prone to referral selection bias.

CONCLUSIONS

This large North American study provides insight on preservative PPTRs and trends from 1994 through 2016.

A comparative study between the two patch test systems Finn chambers and Finn chambers AQUA

BACKGROUND

Finn Chambers AQUA (FCA) is a development of the Finn Chambers (FC) test system in which the test chambers are mounted on a moisture-resistant adhesive patch. FCA has pre-fixed filter papers. Because the use of FCA does not require any extra taping or use of separate filter papers, a change from FC to FCA chambers may be beneficial for both patients and patch test technicians.

OBJECTIVES

To investigate whether there are any differences regarding detection of contact allergy when simultaneous patch testing is performed with FC and FCA.

MATERIALS AND METHODS

Results from 434 dermatitis patients simultaneously tested with 10 allergens in both FC and FCA were evaluated.

RESULTS

There were no significant differences regarding detection of positive reactions between the two test systems. There were significantly more doubtful reactions to methylisothiazolinone, fragrance mix I and hydroperoxides of linalool when testing with FCA. We only observed significantly more doubtful reactions in FC regarding nickel(II)sulfate. Irritant reactions to formaldehyde were also significantly more common when using FCA.

CONCLUSION

The FC and FCA had good agreement in detection of positive reactions. However, the results including doubtful and irritant reactions justify further research regarding optimization of the dose.

Suitable test concentration of cobalt and concomitant reactivity to nickel and chromium: A multicentre study from the Swedish Contact Dermatitis Research Group

BACKGROUND

In Sweden, cobalt chloride 0.5% has been included in the baseline series since the mid-1980s. A recent study from Stockholm showed that cobalt chloride 1% petrolatum (pet.) was more suitable than 0.5%. Cobalt chloride at 1.0% has been patch tested for decades in many European countries and around the world.

OBJECTIVES

To study the suitability of patch testing to cobalt 1.0% vs 0.5% and to analyze the co-occurrence of allergy to cobalt, chromium, and nickel.

RESULTS

Contact allergy to cobalt was shown in 90 patients (6.6%). Eighty (5.9%) patients tested positive to cobalt 1.0%. Thirty-seven of the 90 patients (41.1%) with cobalt allergy were missed by cobalt 0.5% and 10 (0.7%) were missed by cobalt 1.0% (P < .001). No case of patch test sensitization was reported. Allergy to chromium was seen in 2.6% and allergy to nickel in 13.3%. Solitary allergy to cobalt without nickel allergy was shown in 61.1% of cobalt-positive individuals. Female patients had larger proportions of positive reactions to cobalt (P = .036) and nickel (P < .001) than males.

CONCLUSION

The results speak in favor of replacing cobalt chloride 0.5% with cobalt chloride 1.0% pet. in the Swedish baseline series, which will be done 2021.

S3 guidelines: Epicutaneous patch testing with contact allergens and drugs - Short version, Part 1

Epicutaneous patch testing is the diagnostic standard for the detection of allergic contact dermatitis. The present guidelines are aimed at residents and board-certified physicians in the fields of dermatology and allergology as well as other medical specialties involved in establishing the indication for patch testing and its execution in patients with contact dermatitis and other forms of delayed-type hypersensitivity. The target audience also includes other health care providers and insurance funds. Based on a systematic literature search and a formal consensus process (S3), the guidelines were developed by dermatologists in collaboration with pediatricians, occupational medicine physicians, nursing staff as well as patient representatives. The systematic methodological approach and appraisal of evidence upon which the recommendations are based are outlined in a separate method report that also contains evidence tables. The guidelines address general aspects of patch testing as well as medicolegal issues. The recommendations given relate to topics such as the indication for patch testing, informed patient consent, as well as the choice of test substances, test chambers and test site, duration of exposure, reading times and interpretation of test reactions. Furthermore, recommendations are provided with respect to endogenous and exogenous factors, specific patient groups (children, pregnant women, immunosuppressed individuals) as well as possible risks and adverse events associated with patch testing using contact allergens. Note: This publication is part 1 of the short version of the S3 guidelines for "Epicutaneous patch testing using contact allergens and drugs" (registry no. 013 - 018; date: March 20, 2019; valid until December 31, 2021). Part 2 of the short version will be published in the next issue. The long version of these guidelines can be accessed at www.awmf.org. The method report is available as online publication (https://www.awmf.org/leitlinien/detail/ll/013-018.html) and contains the evidence tables in its appendix.

Utilization, cost, and provider trends in patch testing among Medicare beneficiaries in the United States from 2012 to 2017

BACKGROUND

Patch testing is the best diagnostic test for allergic contact dermatitis. However, there is presently a lack of data on the test's geographic availability and the characteristics of the providers offering this test across the United States.

OBJECTIVE

To evaluate the geographic variation in the availability of patch testing for the Medicare population and to characterize the temporal trends of patch testing cost, use, and provider specialty from 2012 to 2017.

METHODS

Retrospective cohort study of the Medicare Provider Utilization and Payment Data from 2012 to 2017.

RESULTS

As of 2017, patch testing was available in 20.3% of metropolitan counties and in 1.1% of nonmetropolitan counties. From 2012 to 2017 in metropolitan regions, the number of beneficiaries tested by dermatologists grew by an average annual growth rate of 1.84%, whereas those tested by allergists grew by an average annual growth rate of 20.31%. Most providers that averaged use of 80 or more patches per beneficiary were dermatologists (76.3%).

LIMITATIONS

Analysis was restricted to Medicare Part B claims; data were unavailable on individuals with commercial insurance.

CONCLUSIONS

Most of the increase in patch testing utilization from 2012 to 2017 has been in metropolitan regions. Although growth was especially prominent among allergists in metropolitan counties, the majority of providers performing comprehensive patch testing were dermatologists.

Improved outcomes in patients with positive metal sensitivity following revision total knee arthroplasty

Background

Metal sensitivity as a cause for painful joint replacement has become increasingly prevalent; however, there is a lack of reported clinical outcome data from total knee arthroplasty patients with metal allergies. The purpose of this study was to determine whether patients presenting with a painful total knee arthroplasty with a positive metal sensitivity have improved outcomes following revision to a hypoallergenic implant.

Methods

A retrospective review was conducted for patients that underwent a revision total knee arthroplasty after metal sensitivity testing over a 3-year period from January 1, 2015, to December 31, 2017. Based on the results of sensitivity testing, patients underwent revision total knee arthroplasty to a hypoallergenic component or a standard component. Following revision, patients returned to the clinic at an interval of 6 weeks, 5 months, and 12 months for functional, pain, and satisfaction assessment. Outcomes were compared within and between sensitivity groups.

Results

Of the included patients, 78.3% (39/46) were positive for metal sensitivity. The most common metal sensitivity was to nickel (79.5%, 32/39). Both non-reactive and reactive patients significantly improved in range of motion after revision arthroplasty. The reactive group saw a 37.8% decrease in pain at 6 weeks post-revision (p < 0.001) Whereas, the non-reactive group only saw a moderate, non-significant improvement in pain reduction at 6 weeks post-revision (27.0%; p = 0.29). Frequency of pain experienced did not vary significantly between groups. Maximum metal lymphocyte transformation test (LTT) sensitivity score did not correlate with pain level at the time of revision (R² = 0.02, p = 0.38) or percent improvement after revision (R² = 0.001, p = 0.81). Overall, all patients reported being very satisfied after revision total knee arthroplasty; there was no difference between positive and negative sensitivity groups (W = 62, p = 0.89).

Conclusions

Patients presenting with a painful knee arthroplasty and positive metal LTT have improved pain scores, walking function, and range of motion following revision to a hypoallergenic component. This study also provides a treatment algorithm for patients presenting with a painful knee replacement, in order to provide effective and timely diagnosis and management.

Electronic supplementary material

The online version of this article (10.1186/s13018-019-1228-4) contains supplementary material, which is available to authorized users.

The role of the dermatologist in the immune-mediated/allergic diseases - position statement of the EADV task force on contact dermatitis, EADV task force on occupational skin diseases, UEMS-EBDV subcommission allergology and European Dermatology Forum

BACKGROUND

The members of the Task Force on Contact Dermatitis and the Task Force on Occupational Dermatoses of the European Academy of Dermatology and Venereology (EADV), of the European Dermatology Forum (EDF), and the members of the UEMS Section of Dermatology-Venereology (UEMS-EBDV) we want to vindicate the fundamental role that the specialist in Dermatology has in the diagnosis and management of Immuno-mediated /allergic Diseases.

OBJECTIVE

In disagreement with the blueprint paper of the UEMS section of Allergology (2013), in which dermatologists are excluded from one of their core activities it was decided to write this consensus paper.

DISCUSSION

The skin occupies a crucial place in the broad spectrum of allergic diseases; there is no other organ with such a multitude of different clinical conditions mediated by so many pathogenetic immune mechanisms. Subsequently, dermatologists play a fundamental role in the management of immune-mediated diseases including among others contact dermatitis, atopic dermatitis, urticaria and angioedema or cutaneous adverse drug, food and arthropod reactions. The essential role of dermatology in the diagnostic, therapeutic and preventive management of immune mediated /allergic diseases which is crucial for patient management is justified from both the academic and professional point of view.

CONCLUSION

Based on the best care of the patient with cutaneous immune allergic disease a multidisciplinary approach is desirable and the dermatologist has a pivotal role in patient management. Be so good and no one will not ignore you, dermatologist. Ideally Dermatology should be governed according the following Henry Ford statement: "Arriving together is the beginning; keeping together is progress; working together is success."

Assessment of patch test results carried out during ten years in a city in southern Brazil

BACKGROUND

Contact dermatitis affects up to 20% of the population. Patch testing for contact allergy may be needed to confirm the diagnosis.

OBJECTIVES

To describe and discuss the results of patch tests performed in a city in southern Brazil.

METHODS

A cross-sectional analysis was performed on all skin test results over ten years. Variables such as gender, age at the time of testing, and test results were evaluated. Triggering factors, duration of complain, and previous medications used related to the clinical history were retrieved for some patients by reviewing their medical records.

RESULTS

The sample was composed of 539 patch tests, of which 411 (76.2%) were from women. The age of the tested subjects ranged from 5 to 87 years. The prevalence of positive reactions in the patch tests was 391 (72.5%). The most prevalent positive reaction was to nickel sulfate (196; 36.4%), which had statistical significance when associated with female gender (p<0,001).

STUDY LIMITATIONS

Database obtained through secondary sources (the reports of the exams and the medical records), occurring the incomplete registration of some information.

CONCLUSIONS

Data analysis at the local level is important to define preventive policies.

Prevalence of contact allergy to metals in the European general population with a focus on nickel and piercings: The EDEN Fragrance Study

Background

Studies on sensitization to metals in the general population are scarce.

Objectives

To determine the prevalence of sensitization to metals in the general population, and factors associated with nickel sensitization.

Methods

In 5 European countries (The Netherlands, Germany, Italy, Portugal and Sweden), a random sample (N = 3119) from the general population (aged 18‐74 years) was patch tested and interviewed by use of a questionnaire on exposure to metals, piercing, and jewellery.

Results

Overall, the age‐standardized prevalences of sensitization to nickel, cobalt and chromium were, respectively, 14.5%, 2.1%, and 0.8%. The highest prevalence of nickel sensitization was seen in Portugal (18.5%) and the lowest (8.3%) in Sweden. The prevalence of cobalt sensitization varied between 3.8% (The Netherlands) and 0.9% (Italy), and the prevalence of chromium sensitization varied between 1.3% (Portugal) and 0.2% (Sweden). Significant associations were observed between nickel allergy and female sex (odds ratio [OR] 5.19; 95% confidence interval [95%CI]: 3.99‐6.74), past piercing use (OR 3.86; 95%CI: 2.85‐5.24), and currently having ≥3 piercings (OR 5.58; 95%CI: 4.02‐7.76).

Conclusions

The prevalence of sensitization to metals in the European general population was high, mostly because of nickel. The lowest prevalence of contact allergy to nickel and chromium observed in Sweden supports the effectiveness of long‐standing regulation.

The reactivity of the back revisited. Are there differences in reactivity in different parts of the back?

BACKGROUND

In the contact dermatitis literature, it is regularly stated that the patch test reactivity on various areas of the back differs, which might have a large impact on the reproducibility of patch testing.

OBJECTIVES

To investigate the reproducibility of patch testing on the upper back with regard to the left as opposed to the right side, and the medial as opposed to the lateral part of the upper back. The reproducibility over time and with regard to the reactivity pattern was also investigated.

METHODS

Thirty-one subjects with contact allergy to the metals gold (n = 19) or nickel (n = 12) were patch tested with serial dilutions, in triplicate applications, on different locations on the upper back. The Friedman test was used for statistical calculations.

RESULTS

No significant differences in the reactivity of the back were found. In all gold-allergic patients and 11 of 12 nickel-allergic patients, the allergy could be reproduced with regard to previous patch testing, but the degree of reactivity differed.

CONCLUSIONS

When a high level of standardization of the patch test technique with the same test system was used, there were no differences in patch test reactions and sites of application on the upper back.

Contact Sensitization in Children: A Retrospective Study of 2,614 Children from a Single Center

BACKGROUND

Contact sensitization in children is more common than previously thought, but few studies have been performed on a large population assessed by the same team. The objective was to evaluate contact sensitization in children with suspected contact dermatitis, the relationship with atopic dermatitis (AD), and the most common allergens.

METHODS

The same team patch tested 2,614 children younger than 11 years old with a standard series of 30 allergens.

RESULTS

A total of 1220 children (46.7%) developed at least one positive reaction, 606 of which were clinically relevant (49.7%). The most frequent reactions were to nickel sulfate (22.7%), cobalt chloride (11.1%), potassium dichromate (9.9%), neomycin sulfate (5.2%), thimerosal (4.2%), cocamidopropyl betaine (3.4%), and methylchloroisothiazolinone/methylisothiazolinone (3.2%). The prevalence of contact sensitization was similar in children with (47.3%) and without (46.1%) AD. Children with AD had a higher prevalence of positive reactions to potassium dichromate (p < 0.001), Compositae mix (p = 0.01), and disperse blue (p = 0.03).

CONCLUSIONS

Contact sensitization is quite common in young children. This study adds some information on the most common contact allergens. A similar prevalence of positive patch test reactions was found in children with and without AD, but children with AD had a greater prevalence of positive patch test reactions to potassium dichromate, Compositae mix, and disperse blue.

International survey on skin patch test procedures, attitudes and interpretation

BACKGROUND

Skin patch test is the gold standard method in diagnosing contact allergy. Although used for more than 100 years, the patch test procedure is performed with variability around the world. A number of factors can influence the test results, namely the quality of reagents used, the timing of the application, the patch test series (allergens/haptens) that have been used for testing, the appropriate interpretation of the skin reactions or the evaluation of the patient's benefit.

METHODS

We performed an Internet -based survey with 38 questions covering the educational background of respondents, patch test methods and interpretation. The questionnaire was distributed among all representatives of national member societies of the World Allergy Organization (WAO), and the WAO Junior Members Group.

RESULTS

One hundred sixty-nine completed surveys were received from 47 countries. The majority of participants had more than 5 years of clinical practice (61 %) and routinely carried out patch tests (70 %). Both allergists and dermatologists were responsible for carrying out the patch tests. We could observe the use of many different guidelines regardless the geographical distribution. The use of home-made preparations was indicated by 47 % of participants and 73 % of the respondents performed 2 or 3 readings. Most of the responders indicated having patients with adverse reactions, including erythroderma (12 %); however, only 30 % of members completed a consent form before conducting the patch test.

DISCUSSION

The heterogeneity of patch test practices may be influenced by the level of awareness of clinical guidelines, different training backgrounds, accessibility to various types of devices, the patch test series (allergens/haptens) used for testing, type of clinical practice (public or private practice, clinical or research-based institution), infrastructure availability, financial/commercial implications and regulations among others.

CONCLUSION

There is a lack of a worldwide homogeneity of patch test procedures, and this raises concerns about the need for standardization and harmonization of this important diagnostic procedure.

European Society of Contact Dermatitis guideline for diagnostic patch testing - recommendations on best practice

The present guideline summarizes all aspects of patch testing for the diagnosis of contact allergy in patients suspected of suffering, or having been suffering, from allergic contact dermatitis or other delayed-type hypersensitivity skin and mucosal conditions. Sections with brief descriptions and discussions of different pertinent topics are followed by a highlighted short practical recommendation. Topics comprise, after an introduction with important definitions, materials, technique, modifications of epicutaneous testing, individual factors influencing the patch test outcome or necessitating special considerations, children, patients with occupational contact dermatitis and drug eruptions as special groups, patch testing of materials brought in by the patient, adverse effects of patch testing, and the final evaluation and patient counselling based on this judgement. Finally, short reference is made to aspects of (continuing) medical education and to electronic collection of data for epidemiological surveillance.

[Bullous rash around a peritoneal dialysis catheter exit site]

BACKGROUND

Cutaneous eruption around a peritoneal dialysis (PD) catheter exit site is a rare complication. Herein we report a case of bullous eruption; we discuss the diagnostic approach and the related therapeutic implications.

PATIENTS AND METHODS

A 63-year-old man presented a bullous periumbilical eruption two months after initiation of PD. Cultures of laboratory samples ruled out an infectious origin and systemic corticosteroids initiated at 0.5mg/kg for suspected eosinophilic peritonitis produced significant improvement of the cutaneous eruption. Recurrence of the bullous eruption was observed upon dose-reduction of the corticosteroid. Skin histology showed a clinical picture of eczema and direct immunofluorescence was negative. Patch testing was carried out using the European Standard Battery comprising antiseptic, cosmetic and plastic series; a semi-open test was performed with the dressing used for PD, and ROAT was carried out on the povidone iodine (Betadine™) 10% used for topical care during PD. The patch testing and ROAT were positive (++), confirming contact dermatitis due to Betadine™. The eruption totally disappeared on substitution of Betadine™ by chlorhexidine for topical antisepsis of the PD catheter, thus enabling PD to be continued rather than instituting hemodialysis.

DISCUSSION

Allergic contact dermatitis around a PD catheter is a rare and little-known complication. In the present case, ROAT testing showed sensitization to Betadine™ and enabled an alternative antisepsis solution to be found, allowing PD to be continued.