Value of photo assessment in late patch test readings-A multicenter study from six European patch test clinics

Three-part scoring system (tripartite) for teledermatology versus International Contact Dermatitis Research Group criteria to interpret patch test readings: A comparative, observational study

Background The International Contact Dermatitis Research Group (ICDRG) grading is the gold standard and is used to interpret patch test results in allergic contact dermatitis (ACD). The ICDRG readings include a combination of visual and palpation findings. Digital photography limits palpation. An alternative scoring system exists to analyse 2D images and interpret patch test readings in teledermatology (TD). Aim To compare tri-partite scoring system (TPSS) (TD) with ICDRG (face-to-face) and to assess the feasibility of TPSS by TD. Methods In this observational study, two investigators each scored the patch test readings for 78 patients at the 48th h, 96th h and on the 7th day. Results The TPSS has a sensitivity of 100%, specificity of 93.34%, positive predictive value of 91.67% and negative predictive value of 100%. At a confidence interval of 95%, Cohen's kappa (0.90) indicated excellent agreement between both investigators. The concordance between both scoring systems was at 93.2% for agreement and 6.82% for disagreement. Polysensitisation (6 patients with 16 allergens) was detected equally in both methods. Limitation A single centre study. Conclusion The readings obtained by TPSS were in agreement with ICDRG. TPSS can reduce the number of patient visits by 50% and may be used during COVID-19 times and beyond.

Prevalence of skin sensitization and dermatitis among epoxy-exposed workers in the wind turbine industry

BACKGROUND

A high prevalence of skin sensitization and dermatitis has been reported among workers exposed to epoxy components.

OBJECTIVES

To estimate the risk of skin sensitization and dermatitis among workers exposed to epoxy components during production of wind turbine blades while using comprehensive safety measures.

METHODS

A cross-sectional study of 180 highly epoxy-exposed production workers and 41 nonexposed office workers was conducted at two wind turbine blade factories in Denmark. Participants underwent a skin examination, were tested with a tailored patch test panel including epoxy-containing products used at the factories, and answered a questionnaire.

RESULTS

Sixteen production workers (8·9%) were sensitized to an epoxy component compared with none of the office workers. Skin sensitization was more frequent within the first year of exposed employment. Strong selection bias by atopic status was indicated. Among nonatopic workers, the prevalence of dermatitis was higher among production workers (16·4%) than among office workers [6·5%, odds ratio (OR) 2·3, 95% confidence interval (CI) 0·6-9·1] and higher among the sensitized workers (43·8%) than the nonsensitized workers (14·6%, OR 4·5, 95% CI 1·6-12·7). Resins based on diglycidyl ether of bisphenol A and F were the most frequent sensitizers. One of the four workers sensitized to epoxy components used at the factories did not react to the epoxy resin of the TRUE test^® panel.

CONCLUSIONS

Despite comprehensive skin protection, sensitization and dermatitis are prevalent among highly epoxy-exposed workers in the wind turbine industry in Denmark. Our findings document the need for intensified preventive efforts and emphasize the importance of tailored patch testing. What is already known about this topic? Epoxy components are well-known sensitizers of the skin. A high prevalence of skin sensitization and dermatitis has been reported among workers exposed to epoxy components. Comprehensive protective equipment is recommended when working with epoxy components. What does this study add? Despite comprehensive skin protection, skin sensitization and dermatitis are prevalent among epoxy-exposed workers. We found that 40% of workers sensitized to epoxy products had dermatitis. Only 75% of the sensitized workers were detected by the epoxy resin of the TRUE test^® , which emphasizes the importance of tailored testing.

The benefit of late readings in patch testing depends both on allergen and patient characteristics

BACKGROUND

Patch test (PT) readings are recommended after 48 h and 72 h (D3). An additional day 7 (D7) reading has been suggested by some, although data on efficient patient selection are scarce. We investigated positive D7 reactions regarding (i) allergens in the baseline series and additional PT series of the German Contact Dermatitis Research Group (DKG) and (ii) characteristics of the patients tested.

METHODS

Retrospective, multicentre analysis of 190 allergens derived from 17 DKG test series in 4687 patients with an additional D7 reading. Patients were patch tested with the baseline series and additional series, if required. Occurrence of novel D7 reactions as well as increasing skin reactions from D3 to D7 was analysed separately.

RESULTS

Depending on the allergen tested, waiving D7 readings would have missed 4.4-26.8% of positive PT results. Patch test series with the highest number of novel D7 reactions were baseline series, metal series, and leather/shoe series. New positive reactions on D7 were associated with age over 50 years and with a negative irritant control containing sodium lauryl sulphate. Of note, application of the PT allergens for 48 h instead of 24 h was positively associated with late PT reactions.

CONCLUSION

Within the most frequently tested allergens, without late readings, on average 11.7% of sensitizations would have been missed. Novel late reacting allergens were identified. This study comprehensively dissects patient-, allergen- and test-dependent parameters in support for D7 readings. We propose to always consider late readings individually based on effort-benefit considerations.

Predictive factors for Day 7 positive patch test readings at a secondary referral centre

Background

Based on studies at tertiary centres it is known that patch test reading on Day (D) 7 may show additional positive reactions. Female gender, higher age and allergen groups of topicals and corticosteroids were identified as predictive factors.

Objectives

The first aim was to study the value of reading patch tests on D2, D3 and D7 at a secondary referral centre. The second aim was to investigate the predictive potential of the factors sex, age, atopic dermatitis, body location, allergen group and clinical relevance for a positive reaction only on D7.

Methods

Retrospective data from patients tested between 2013 and 2016 were evaluated. The factors sex, age, atopic dermatitis, body location, allergen group and clinical relevance were tested by regression analysis.

Results

Two hundred and sixty-three out of a total of 396 patients had a positive reaction only on D2, D3 and D7 in 14 (2.5%), 152 (27.5%) and 61 (11.0%) occasions, observed in 10 (2.5%), 108 (27.3%) and 51 (12.9%) patients, respectively. These reactions were deemed relevant in 0 (0%), 12 (2.2%) and 9 (1.6%) occasions, observed 0 (0%), 11 (2.8%) and 9 (2.3%) patients, respectively. Higher age and allergen groups of metals, fragrances and resins were predictive for late positive reactions.

Conclusions

D7 patch test reading should also be routinely adopted at secondary referral centres. D7 positive reactions were associated with higher age and sensitization to metals, fragrances and resins.

Allergic contact dermatitis from ("hypoallergenic") adhesives containing D-limonene

BACKGROUND

Besides being a potential component of (some species of) colophonium, D-limonene is also used as a tackifier in the production of adhesives. Hydroperoxides of limonene are well-known skin sensitizers.

OBJECTIVES

To show that D-limonene may be present in colophonium-containing but also colophonium-free ("hypoallergenic") adhesives, and that patients suffering from allergic contact dermatitis (ACD) from both types of adhesives might display positive patch test reactions to limonene hydroperoxides in this regard.

METHODS

Five patients with suspected ACD from adhesives were patch tested to the baseline series (containing limonene hydroperoxides 0.3 and 0.2% pet.), additional series and, if available, to the culprit adhesives. The adhesives labelled as containing colophonium (n = 3) or free from it (n = 2) were analysed with gas chromatography - mass spectrometry (GC-MS) for the presence of D-limonene.

RESULTS

All five patients sensitised to adhesives had (strong) positive patch test reactions to limonene hydroperoxides. The presence of D-limonene, and/or related components, could be demonstrated in all three colophonium-containing and, surprisingly, also in two colophonium-free ("hypoallergenic") tapes.

CONCLUSIONS

D-limonene may be present in both regular and "hypoallergenic" adhesives, with limonene hydroperoxides potentially contributing to ACD from such medical devices. The use of fragrance chemicals in adhesives deserves further research.

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.