Aluminum—Allergen of the Year 2022

Abstract

Exposure to elemental aluminum and its salts is unavoidable. Aluminum as a metal is present in transport, construction, packaging, and electronic equipment. Aluminum salts are present in consumer products, food items and drinking water, vaccines, drugs, and antiperspirants. Aluminum in vaccines and preparations for allergen-specific immunotherapy are the major sensitization sources. The predominent clinical manifestations of aluminum allergy are pruritic subcutaneous nodules and eczematous dermatitis. Patch testing shall be performed with aluminum chloride hexahydrate (ACH) in petrolatum. The preparation with ACH 10% detects substantially more aluminum allergy than ACH 2%. A patch test with elemental aluminum, for example, an empty Finn Chamber, is only positive when there is a strong aluminum allergy. A patch test reading should be performed 1 week after the application so as not to miss 15% to 20% of aluminum allergy. Aluminum should be included in any baseline patch test series for children and investigated for a possible inclusion in baseline series for adults. Aluminum test chambers can interfere with the testing resulting in both false-negative and false-positive patch test reactions to nonaluminum contact sensitizers.A luminum has within the periodic system the symbol Al and atom number 13. Its weight is 26.98. Aluminum is the third most abundant element in the Earth's crust; approximately 8% of the crust consists of aluminum. It is rare to find aluminum in its elemental form because it is too reactive. Pure aluminum virtually always forms compounds by bonding to other elements, oxygen being a favorite. In our environment, aluminum is present as oxides. EXPOSUREAluminum is widely used and contact with its elemental form or its salts is unavoidable. The metal form of aluminum has many advantages because it is soft, nonmagnetic, light, corrosion resistant, and recyclable. Aluminum as a metal is, therefore, used in applications such as in transport, packaging, construction, electronic equipment, household goods, and as alloys in medicine and dentistry. Aluminum as a trivalent metal cation, Al 3+ , can be found in many different aluminum salts with various properties. These salts are, therefore, used in industry, cosmetics, sunscreens, dental restorations, food, and medicine. [1][2][3] Aluminum is also found in drinking water. 3 Examples of the use of aluminum salts include aluminum sulfate, which is used in water purification and paper production. Aluminum acetate and aluminum acetotartrate are used as astringents in solutions. Aluminum chloride hexahydrate (ACH) and aluminum chlorohydrate are used in antiperspirants. In antacids, aluminum hydroxide can be used. Aluminum hydroxide and aluminum phosphate are added to many vaccines to enhance the immune response in the treated individuals. Aluminum may also be found in tattoo pigments. 4

Aluminum: The 2022 American Contact Dermatitis Society Allergen of the Year

“…As the third most common element in the Earth's crust, aluminum can be found quite literally everywhere. 1 However, aluminum rarely is found in its pure elemental form; instead, it reacts with other elements around it, most commonly oxygen, to form aluminum-containing compounds. Known for their stability and safety, aluminum and its salts are incorporated in myriad products ranging from electronic equipment to foods and their…”

“…Contact allergy to elemental aluminum is rare; on the other hand, aluminum salts (the forms we are likely to encounter in daily life) are now recognized in the field of contact dermatitis as allergens of significance, particularly in the pediatric population. 1,6 First reported as a possible occupational allergen in 1944, 7 aluminum allergy came to prominence in the 1990s in association with vaccines. Aluminum is included in some vaccines as an adjuvant that bolsters the immune response 8 ; the eTable lists currently available aluminumcontaining vaccines in the United States; of note, none of the COVID-19 vaccines approved in the United States or Europe contain aluminum.…”

“…22 With this evidence in mind, it has been recommended by contact dermatitis experts that aluminum be included in pediatric baseline patch test series and also investigated for potential inclusion in baseline series for adults. 1…”

“…Due to its physicochemical properties, patch testing for aluminum allergy is complicated, and historically there has been a lack of consensus on the ideal test formulation. 1,27,28 At this time, it appears that the most sensitive formulation for patch testing to aluminum is ACH 10% in petrolatum. 1 Some contact dermatitis experts recommend that children younger than 8 years should be tested with ACH 2% in petrolatum to minimize the risk of extreme patch test reactions.…”

“…The 2022 Allergen of the Year is likely to be lurking in your kitchen drawer at this very moment, as this year aluminum was chosen for this most prestigious honor. 1 But do not throw out your aluminum foil just yet-aluminum allergy tends to be confined to specific scenarios. In this article, we highlight the growing recognition of aluminum contact allergy, particularly in the pediatric population, focusing on distinct presentations of aluminum ACD, unique sources of exposure, and nuances of patch testing to this metal.…”