BOSTON – The . Aluminum salts, which are the major cause of allergic reactions, are “ubiquitous,” Donald Belsito, MD, professor of dermatology at Columbia University, New York, said at the annual meeting of the American Contact Dermatitis Society.
These salts can be found in sunscreen, cosmetics, dental restorations, and food, to name a few, though the most commonly identified reactions are from aluminum hydroxide, which can be found in some vaccines or preparations for allergen-specific immunotherapy. “It’s the aluminum hydroxide that seems to be more allergenic than other aluminum salts,” Dr. Belsito said in an interview.
“It’s not a dangerous allergy; It’s not a threat,” he said, “but it’s something that dermatologists need to be aware of.”
These reactions normally present as itchy nodules that can last for months and even years, like some reactions from patch testing. “We’re not talking about a vaccine allergy in such a way where people are getting anaphylaxis,” JiaDe Yu, MD, a pediatric dermatologist specializing in allergic contact dermatitis at Massachusetts General Hospital, Boston, said in an interview. “An itchy rash is what we tend to see.”
There have also been occasional reports of atopic dermatitis from aluminum in antiperspirants, astringents, as well as from the metallic aluminum.
Dr. Yu noted that aluminum allergies are not thought to be very common, but the overall prevalence is not known. Studies do suggest, however, that the allergy may be more prevalent in children. In one recent study in Sweden, 5% of children and 0.9% of adults who underwent patch testing had an aluminum contact allergy.
Recommendations for testing
Aluminum is not included in baseline patch testing in the United States, though a recent report about the allergen in the journal Dermatitis argued for its inclusion for pediatric patch testing. Both Dr. Belsito and Dr. Yu agreed that the best approach is to do targeted testing. “If there is a suspicion for it, absolutely test for it,” Dr. Yu said, but if a patient comes in with something like eyelid dermatitis or a rash after a hair care appointment, an aluminum allergy is not very likely.
Because aluminum is also present in Finn Chambers for patch testing, Dr. Belsito advised using plastic chambers in people suspected of having an aluminum allergy. He now uses only plastic chambers in children, he said, as some patients have had reactions to the Finn Chambers even if they have no history of reactions to vaccines or other aluminum-containing products.
While aluminum chloride hexahydrate (ACH) 2% in petrolatum is the commercially available preparation in patch testing, a preparation with ACH 10% is more sensitive, Dr. Belsito said. If a physician strongly suspects an aluminum allergy in a patient but the test with the ACH 2% is negative, he or she should then try a 10% solution, he noted, adding that 7-day readings are also necessary to maximize accuracy.