Sulfites: No Longer a Zebra?

Sulfites: Allergen of the Year 2024

Sodium disulfite, also known as sodium metabisulfite or sodium pyrosulfite, is an inorganic compound, which may cause allergic contact dermatitis. Sulfites act as antioxidants and preservatives; common sources include food/beverages, pharmaceuticals, and personal care products. Importantly, sulfites are not included in most screening patch test series and thus may be missed as a relevant contact allergen. The American Contact Dermatitis Society chose sulfites as the Allergen of the Year for 2024 to raise awareness about this significant allergen.

Sulfites

The Expert Panel for Cosmetic Ingredient Safety reviewed newly available studies since their original assessment in 1998, along with updated information regarding product types and concentrations of use, and confirmed that Sodium Sulfite, Potassium Sulfite, Ammonium Sulfite, Sodium Bisulfite, Ammonium Bisulfite, Sodium Metabisulfite, and Potassium Metabisulfite are safe as cosmetic ingredients in the practices of use and concentration as described in this report.

Patch Test Reactions Associated With Topical Medications: A Retrospective Analysis of the North American Contact Dermatitis Group Data (2001-2018)

BACKGROUND/OBJECTIVES

Topical medications may lead to allergic contact dermatitis. This study characterized positive patch test reactions associated with medications in patients evaluated by the North American Contact Dermatitis Group (NACDG).

METHODS

This study is a retrospective analysis of the NACDG data (2001-2018). Patients with at least 1 positive patch test reaction associated with a medication source were included. Allergens, reaction characteristics, clinical relevance, and source details were tabulated.

RESULTS

Of 43,722 patients, 6374 (14.6%) had positive allergic patch test reactions associated with 1 or more topical medication sources. Patients with versus without allergic reactions to medications were more likely to be older than 40 years (P < 0.0001) and/or have primary sites of dermatitis on the legs, anal/genital region, or trunk (P < 0.0001). There were 8787 reactions to NACDG allergens; the most common were neomycin (29.4%), bacitracin (29.1%), propylene glycol 100% (10.6%), tixocortol-17-pivalate (10.0%), lidocaine (7.9%), budesonide (4.9%), and dibucaine (4.4%). Propylene glycol 100% was the most common inactive ingredient (10.6%). Current relevance was present in 61.0%. A total of 6.5% of the individuals with medication allergy would have had 1 or more positive patch test reactions missed if only tested to the NACDG screening series.

CONCLUSIONS

Positive patch test reactions associated with topical medications were common (14.6%), and most were clinically relevant. Patients with topical medication allergy were twice as likely to have anal/genital involvement. Active ingredients, especially neomycin, bacitracin, and tixocortol-17-pivalate, were frequent culprits.

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.

Isothiazolinone in Residential Interior Wall Paint: A High-Performance Liquid Chromatographic-Mass Spectrometry Analysis

BACKGROUND

There is limited information regarding isothiazolinone content in residential wall paints in the United States.

OBJECTIVE

The aim of this study was to evaluate the prevalence of 5 isothiazolinones-methylisothiazolinone (MI), methylchloroisothiazolinone, benzisothiazolinone (BIT), butyl BIT, and octylisothiazolinone-in US residential wall paints.

METHODS

Forty-seven paints were obtained from retailers in Minneapolis/St Paul, Minnesota. Paint samples were assessed for the presence of the 5 isothiazolinones using high-performance liquid chromatographic-mass spectrometry.

RESULTS

At least 1 isothiazolinone was detected in all 47 paints. However, no paint contained butyl BIT, and only 1 paint had octylisothiazolinone. The MI and BIT were found in 96% and 94% of the paints, respectively. Methylisothiazolinone ranged in concentration from 17 to 358 ppm, whereas BIT varied from 29 to 1111 ppm. Methylchloroisothiazolinone was found solely in oil-based paints. Isothiazolinones were declared in 15% of Safety Data Sheets but did not correlate with high-performance liquid chromatographic-mass spectrometry. One "preservative-free" paint had BIT at 71.5 ppm. Paint sheen was not statistically associated with BIT or MI concentrations. Unpigmented paints and paints with volatile organic compound claims had significantly lower concentrations of MI, but not BIT.

CONCLUSIONS

All paints contained at least 1 isothiazolinone. Methylisothiazolinone and BIT were the most common. Safety Data Sheets are insufficient for ascertaining isothiazolinone content in US paints.