UV sunlight and patch test reactions in humans

Multiyear Group and Medical Center Patch Test Frequency Data: Confounding Variables

Patch test frequency data have been extensively published by research groups, such as the International Contact Dermatitis Research Group, North American Contact Dermatitis Group, Dermato-Allergology Study and Research Group, and European Environmental Contact Dermatitis Research Group. As this knowledge accumulation is widely applied in clinical and public health settings, we describe confounding factors to consider when using such data for medical policy considerations. These concepts can also be used in individual reports of new allergens or series of cases. Some of these confounders may have been reported in current literature (until October 2020), whereas others have not been mentioned/considered in most group publications.

Seasonal Variation in Patch Test Results with European Baseline Series

Aim

To study the influence of season on patch tests results.

Methods

We conducted a retrospective epidemiological study which concerned all the patients of the Tunisian center, who consulted in the Dermato-Allergology Unit of Occupational Medicine Department of Farhat Hached University Hospital-Sousse (Tunisia) over a period of 07 years. All the patients were tested by the European Standard Battery allergens (BSE).

Results

The data of 1000 patch tests were analyzed during the study period. More than half of the patch tests (58.6%) was positive. In winter, 63% of patch tests showed a positive reaction versus 52% of patch tests in summer without a statistically significant association. However, results of lanolin alcohols, epoxy resin, and Sesquiterpene lactone mix varied significantly with season. Atopy was significantly associated with 18.8% of positive reactions in winter and only with 5.2% of positive reactions in summer (p = 0.015).

Conclusion

Seasonal variations in patch tests results were more significant with some allergens of European Standard Battery and in atopic patients.

S3 Guidelines: Epicutaneous patch testing with contact allergens and drugs - Short version, Part 2

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.

Another look at seasonal variation in patch test results. A multifactorial analysis of surveillance data of the IVDK. Information Network of Departments of Dermatology

There is conflicting evidence concerning seasonal variability of patch test results and no evidence concerning the influence of season on weak-positive, possibly false-positive, irritant reactions, which was analysed in the present study. Data collected in the German Information Network of Departments of Dermatology (IVDK) 1992 to 1997 were combined with external environmental data on temperature and absolute humidity in Germany, and bivariate as well as logistic regression analyses performed concerning the association between reactivity to selected allergens and air temperature and absolute humidity on the respective days of patch testing. Between 39,239 and 41,629 patients had been tested with the 4 allergens considered here. Only formaldehyde exhibited a distinct increase in questionable or irritant as well as weak-positive reactions associated with dry, cold weather. Methylchloroisothiazolinone/methylisothiazolinone and lanolin alcohol showed only a weak, and epoxy resin no, association with climatic conditions. The results indicate that weak-positive reactions, at least to formaldehyde as a prototype of an allergen which is at the same time a marginal irritant, may sometimes be irritant rather than allergic. Patients showing these should be re-tested to improve the poor reproducibilty observed with this allergen.

Prevalence of delayed hypersensitivity to the European standard series in a self-selected population

There are limited reports of the prevalence of positive reactions in healthy adults to patch tests with standard allergens; there are no recent comprehensive studies from Australia. Healthy adult volunteers (n = 219) from the Western Australian community were patch tested using the European standard series of allergens. Seventy-seven (35%) reacted to at least one allergen, positive patch tests being most prevalent to nickel sulfate (20%), potassium dichromate (9%), cobalt chloride (6%) and fragrance mix (4%). Prevalence of positive patch tests to nickel and chromate was higher than that reported for another healthy population, which may stem from self-selection of volunteers or geographical differences, including extent of exposure to allergens.