16/05/2024
Sulfites, present in food, drinks, pharmaceuticals and personal care products, have been named the "Allergen of the Year" for 2024 by the American Contact Dermatitis Society (ACDS). Sulfites are currently not in most screening patch test series, so may be missed as a relevant contact allergen, Donald Belsito, MD, emeritus professor in the Department of Dermatology at Columbia University, New York City, said in his presentation on the Allergen of the Year on March 7 at the ACDS Annual Meeting in San Diego. Sulfites, he noted, are distinct from sulfates, and the groups do not cross-react with each other.
Sodium disulfite, an inorganic compound, belongs to a group of sulfiting agents, which contain the sulfite ion SO32β and include ammonium sulfite, potassium sulfite, and sodium sulfite. They function as antioxidants and preservatives in a range of products including food and beverages (especially wine), personal care products and pharmaceuticals.
The type of sulfite allergy diagnosed by patch testing is type IV hypersensitivity or delayed-type hypersensitivity, where patients present with pruritic, red, scaling macules, papulovesicles, and patches, Belsito told Medscape Medical News. "It is not the type I, immediate hypersensitivity that causes hives and, in some cases, anaphylaxis," he said. But sulfites also can cause these side effects, so correct labeling of food and beverages is important.
Some common nonoccupational sulfite sources include hair colouring and bleach products, hairspray, tanning lotions, makeup, sunscreens and deodorants, Belsito said in his presentation. Medications including topical antifungals, topical corticosteroids, and nasal solutions can be culprits, as can water in swimming pools.
High-sulfite food products (> 100 ppm) to be aware of include dried fruit (raisins and prunes are exceptions), bottled lemon or lime juice (but not frozen products), wine, molasses, grape juice (white, or white, pink, and red sparkling) and pickled cocktail onions.
"Like other contact allergens, the clinical presentation correlates with exposure," he added. A study by the North American Contact Dermatitis Group (NACDG) found that 28.8% of patients positive for sulfite allergy on patch testing presented with facial dermatitis, which was not only related to cosmetics and medications used on the face, but also from products, such as shampoo used on the scalp that dripped onto the face. "The scalp is relatively resistant to the expression of contact allergy and may not be involved at all," he said.
According to the NACDG study, the hands were the second most common site of dermatitis associated with sulfites (20.5%) followed by a generalised distribution (13.6%). These sites are to be expected, given the sources of food and beverage, personal care products, and occupational materials, Belsito said.
"Eczematous dermatitis of the lips is also common in patients with ingested food sources of sulο¬tes," he said.
Systemic contact dermatitis to sulο¬tes has been documented following oral, re**al, and parental exposure, Belsito told Medscape Medical News. "Systemic dermatitis may present as a scattered/generalised dermatitis, symmetrical drug-related intertriginous and flexural exanthema (also referred to as baboon syndrome), or erythroderma," he said.
For more information see https://www.medscape.com/viewarticle/sulfites-selected-acds-allergen-year-2024a10004hd