Allergic contact dermatitis due to sodium metabisulfite in a bleaching cream

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.

Topical sodium metabisulfite for the treatment of calcinosis cutis: a promising new therapy

Calcinosis cutis is a chronic calcium-mediated disease that causes significant morbidity. Multiple treatments have been tried, with varying results; indeed, to date, no standard treatment has been generally accepted. Sodium metabisulfite is an inorganic compound that, when it reacts with oxygen, becomes sodium sulfate, a metabolite of sodium thiosulfate that has a similar ability to inhibit calcium oxalate agglomeration. Four women diagnosed with calcinosis cutis, secondary to dermatomyositis, systemic sclerosis and radiodermatitis after breast cancer, were evaluated for their response to topical 25% sodium metabisulfite. In all patients a decrease in lesion size, erythema and pain from injuries was shown, with complete resolution of the associated ulcers. One patient had a complete response. None experienced adverse effects. Topical sodium metabisulfite is a promising emerging therapy that should be considered as a valid alternative treatment in calcinosis cutis. Randomized prospective studies are required to evaluate its true efficacy.

Sodium metabisulfite allergy is common but is it relevant?

Positive patch tests to sodium metabisulfite (SMB) are frequent. Standard series patch testing to SMB in 1751 patients showed 71 reactions interpreted as positive and allergic. 33 (46.5%) reactions were originally reported as relevant and 38 (53.5%) were of unexplained relevance depending on the presence or absence of identifiable sources responsible for the presenting dermatitis. A breakdown of these findings is presented. An additional detailed study of the sources of SMB in the environment and a retrospective analysis of these results have been undertaken to identify further, possibly overlooked sources of SMB exposure based on the occupational and recreational history. Most of the positive reactions in the relevant group were attributed to the use of Trimovate cream (63%). 5 patients (13%) with positive reactions in the unexplained relevance group were potentially exposed to SMB in local anaesthetic solutions while at work. 3 patients in the unexplained relevance group (7.8%) and 4 (12.1%) in the relevant group had potential for occupational exposure to SMB as bakers or caterers. Overall, occupational exposure was considered as a possible source of sensitization in 10 (26.3%) patients in the unexplained relevance group. We propose that sensitization to SMB from parenteral solutions and occupational exposure from food handling may account for some of the otherwise unexplained positive patch test reactions. A detailed occupational history should be therefore be sought in otherwise unexplained positive reactions to SMB. We also propose that it is worthwhile including SMB in our standard series in the UK.