Thresholds for Contact Allergy to a Rubber Accelerator: TETD-Determined by Serial Dilution Patch Testing and a Simulated Glove-Use Model.

BACKGROUND

Rubber accelerators found in rubber gloves may cause contact allergy and thus allergic contact dermatitis.

OBJECTIVES

To investigate which doses of tetraethylthiuram disulfide (TETD) elicit allergic contact dermatitis by patch testing and in a repeated occluded application test simulating glove use.

PATIENTS AND

METHODS

A multicentre study was conducted. Eight patients with contact allergy to TETD and eight controls comprised the study group. Doses of TETD 1% (400 μg/cm2), 0.33% (130 μg/cm2), 0.11% (44 μg/cm2), 0.037% (15 μg/cm2), 0.012% (4.9 μg/cm2), 0.0041% (1.6 μg/cm2) and pure vehicle (petrolatum) were used for the patch test. Doses of TETD 1% (39 μg/cm2), 0.33% (13 μg/cm2), 0.11% (4.3 μg/cm2) and pure vehicle (99:1 ethanol: water) were used for the repeated occluded application test.

RESULTS

Three patients (3/8) reacted to the lowest TETD dose of 0.0041% (1.6 μg/cm2) in the patch test. All patients reacted to all doses of TETD in the repeated occluded application test, none to the vehicle. The patch test dose of TETD that elicited allergic contact dermatitis in 10% of the patients (ED10) was estimated to be 0.75 μg/cm2.

CONCLUSION

A content of 0.75 μg/cm2 TETD in rubber gloves may elicit allergic contact dermatitis. We suggest that future studies investigating contact allergy to rubber accelerators should base their methodology on the repeated occluded application test design presented in this study.

TRIAL REGISTRATION: ClinicalTrial.gov identifier: NCT06042309.