Occupational contact dermatitis caused by hydrogenated formaldehyde-benzenamine polymer (FBAP) in epoxy hardeners

The additive value of patch testing non-commercial test substances and patients' own products in a clinic of occupational dermatology

BACKGROUND

Commercial patch test substances don't cover all occupational contact allergens. Workplace materials and in-house test substances are tested to complement the investigation of occupational skin disease (OSD).

OBJECTIVES

To quantify the additional value of testing workplace materials and non-commercial in-house test substances in the diagnosis of OSD.

MATERIALS AND METHODS

Patients files of 544 patients patch tested at the Finnish Institute of Occupational Health in 2015-2019 were reviewed for occupation, diagnoses, and patch test results.

RESULTS

OSD was diagnosed in 353 (64.9%) of the patients. 206 (37.9%) patients had occupational allergic contact dermatitis (OACD). In 19 (3.5%) patients, the only clues to the diagnoses of OACD were positive reactions to workplace materials, and in 20 (3.7%) patients, the diagnosis of OACD was based on commercially unavailable test substances. In 167 OACD cases diagnosed by commercial test substances, additional causes were found in 17 by testing patients' own and non-commercial test substances. In 43 (7.9%) cases, positive reactions to workplace materials reinforced diagnoses based on commercial test substances. The overall additive value of testing own products was 16.7% (91 cases).

CONCLUSIONS

We would have missed 39 (18.9%) of our 206 OACD cases if we had solely used commercial test substances. This article is protected by copyright. All rights reserved.

Characterization of patients with occupational allergy to two new epoxy hardener compounds

Background

The practical importance of two recently described epoxy hardener allergens—1,3‐benzenedimethanamine, N‐(2‐phenylethyl) derivatives (1,3‐BDMA‐D) and hydrogenated formaldehyde benzenamine polymer (FBAP)—as occupational allergens remains to be defined.

Objectives

To describe patients diagnosed at the Finnish Institute of Occupational Health (FIOH) with positive reactions to 1,3‐BDMA‐D or FBAP.

Methods

We searched FIOH's patch‐test files from January 2017 to December 2020 for patients examined due to suspected occupational contact allergy to epoxy compounds. We analyzed the patch‐test results and sources of exposure to various epoxy hardeners and focused on occupations, symptoms, and the sources of exposure to 1,3‐BDMA‐D and FBAP.

Results

During the study period, 102 patients were examined at FIOH for suspected occupational contact allergy to epoxy compounds. Of these, 19 (19%) were diagnosed with contact allergy to 1,3‐BDMA‐D (n = 10) or FBAP (n = 12). The largest occupational group was sewage pipe reliners (n = 8). Seven different hardener products contained FBAP, whereas 1,3‐BDMA‐D was present in only one hardener used by spray painters.

Conclusions

A substantial number of patients with suspected occupational epoxy resin system allergy tested positive to in‐house test substances of 1,3‐BDMA‐D and/or FBAP.

[New allergens for occupational dermatology?]

BACKGROUND

The environment is continuously subject to change. Exposures in the work environment and therefore the importance of occupational type I and type IV allergens may change.

OBJECTIVES

The most important trends concerning occupational allergens, new occupational allergens/allergen exposures, the diagnostic procedure to detect new allergens in practice and regulatory developments are presented.

MATERIALS AND METHODS

Building on known relevant allergen exposures in occupational dermatology, published trends from clinical cohorts are evaluated and a systematic literature search (PubMed 2016-2021) for new occupational allergens is also performed RESULTS: Occupations with the highest incidence of occupational allergic contact urticaria and/or protein contact dermatitis include bakers, farmers and farm workers, veterinary technicians, veterinarians, cooks, dairy and livestock workers, gardeners, and hairdressers. The highest risk of developing occupational contact dermatitis is in health care, agriculture, metalworking occupations and machine operators, the food sector, service industries, and construction occupations. The search strategy "new occupational allerg*" yielded 603 hits and "novel occupational allerg*" 158 hits. A total of 25 papers included results relevant to the research question and were processed. New protein-based immediate-type allergens, as well as contact allergens (haptens) relevant for occupational dermatology, are presented.

CONCLUSIONS

Current trends on known occupational allergens and new occupational allergens in the period 2016-2021 can be identified. Only a thorough individual workplace history and testing of patients' own materials can identify new allergens in occupational dermatology.

Contact Allergy: A Review of Current Problems from a Clinical Perspective

Contact allergy is common, affecting 27% of the general population in Europe. Original publications, including case reports, published since 2016 (inclusive) were identified with the aim of collating a full review of current problems in the field. To this end, a literature search employing methods of systematic reviewing was performed in the Medline^® and Web of Science™ databases on 28 January 2018, using the search terms (“contact sensitization” or “contact allergy”). Of 446 non-duplicate publications identified by above search, 147 were excluded based on scrutiny of title, abstract and key words. Of the remaining 299 examined in full text, 291 were deemed appropriate for inclusion, and main findings were summarised in topic sections. In conclusion, diverse sources of exposures to chemicals of widely-differing types and structures, continue to induce sensitisation in man and may result in allergic contact dermatitis. Many of the chemicals are “evergreen” but others are “newcomers”. Vigilance and proper investigation (patch testing) are required to detect and inform of the presence of these haptens to which our populations remain exposed.