Relevance of contact sensitizations in occupational dermatitis patients with special focus on patch testing of workplace materials.

Background: Studies on patch testing with workplace materials and evaluation of current occupational relevance of positive patch test reactions are scarce in patients with occupational dermatitis (OD).
Objectives: To identify frequent sensitizations with occupational relevance and to determine the value of patch testing with workplace materials in OD patients.
Patients and Methods: Results and clinical data of 654 patients with suspected OD patch tested between 2013 and 2017 were analysed.
Results: Occupational allergic contact dermatitis was diagnosed in 113 (17.3%) patients. Mechanics had the widest range of occupational sensitizations. Sensitization to epoxy resin was rated occupationally relevant in almost all handicraft trades. Among positive patch test reactions to workplace products, those to water-based metal working fluids and leave-on cosmetic products were most frequent. Despite frequent testing, protective gloves only rarely elicited positive reactions. Preservatives and rubber compounds were most frequently identified as currently occupationally relevant.
Conclusions: Rubber allergy is occupationally relevant especially in healthcare workers and cleaners. Generally, preservatives including formaldehyde releasers are important allergens in OD patients. Leave-on cosmetic products must not be forgotten as allergen sources. Patch testing both workplace materials and standardized test preparations has a complementary value and is beneficial for the diagnostic work-up of OD patients.
(© 2020 The Authors. Contact Dermatitis published by John Wiley & Sons Ltd.)