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

Abstract

SummaryEpicutaneous 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.

Improving povidone‐iodine and iodine preparations for patch testing

“…We further addressed the benefit of late readings in iodine patch testing because the current literature has described up to 15% more positive reactions, in general, for readings at D7. 8 In this respect, some allergens are well known for delayed positive reactions, for example, neomycin. In brief, there was no relevant additional information at D7 beyond the results from D3; that is, we would not have missed any relevant test result without D7 readings.…”

“…Patch tests were performed with 48 hour exposure through the use of Finn Chambers (8 mm inner diameter) on Scanpor tape (Smart-Practice, Greven, Germany) and read at D2, D3, and D7, according to the current guidelines of the German Contact Dermatitis Research Group. 8,9 This retrospective study was reviewed and approved by the local ethics committee at the University Medical Center Göttingen.…”

Optical coherence tomography for patch test grading: A prospective study on its use for noninvasive diagnosis of allergic contact dermatitis

“…Patch‐test reactions are assessed by visual inspection, supported by palpation, and based on morphological clinical criteria (erythema, infiltration, papules, vesicles, confluent vesicles) 5,6,19 . However, even reactions classified as positive could turn out to be irritant, so that a clinical follow‐up after 1 or 2 days may be required.…”

Contact sensitization in metalworkers: Data from the information network of departments of dermatology (IVDK), 2010–2018

“…Patch testing and evaluation of reactions are performed according to DKG guidelines. 14,15 For the present data analysis, patch test reactions at day 3 (D3) were considered. In a few exceptional cases, when a PT reading was performed at D4 instead of D3, this reading From January 2010 to December 2018, a total of 107 288 patients were patch tested in the departments of dermatology which are members of the IVDK.…”

“…All IVDK members are also members of the German Contact Dermatitis Research Group (DKG). Patch testing and evaluation of reactions are performed according to DKG guidelines 14,15 . For the present data analysis, patch test reactions at day 3 (D3) were considered.…”