Patch testing with sodium disulfite: North American Contact Dermatitis Group experience, 2017 to 2018.

Background: Sodium disulfite (SD), also known as sodium metabisulfite, is an increasingly recognized cause of allergic contact dermatitis.

Objectives: The objective of this work was to characterize individuals with positive patch test reactions to SD as well as analyse reaction strength, clinical relevance, and sources.

Methods: This is a retrospective analysis of patients patch tested with SD (1% petrolatum) by the North American Contact Dermatitis Group (NACDG), 2017 to 2018.

Results: Of 4885 patients patch tested with SD, 132 (2.7%) had a positive reaction. Common primary anatomic sites of dermatitis were face (28.8%), hands (20.5%), and a scattered/generalized distribution (13.6%). Compared with SD-negative patients, SD-positive patients were more likely male (odds ratio 2.81, 95% confidence interval 1.98-4.00) and/or over 40 years (odds ratio 1.95, 95% confidence interval 1.30-2.94). Reactions were most commonly + (50.4%) or ++ (34.1%); 65.2% were considered currently relevant. About 15.2% were definitively confirmed in sources, commonly personal care products (18.9%, especially hair dye), and drugs/medications/alcoholic beverages (9.1%). Only 2.3% of positive reactions were linked to occupation.

Conclusions: Positive reactions to SD occurred in 2.7% of tested patients. Reactions were often clinically relevant and linked to personal care products and drugs/medications/alcoholic beverages.