ABSTRACT
Although there exist an abundance of different metals, most humans are only exposed to a minority of them, and only some cause sensitization. Metals are mainly allergenic as salts and not in their metallic form. Although type IV hypersensitivity reactions such as allergic contact dermatitis (ACD) to metals are well-documented and frequent,[1] type I hypersensitive reactions to metals including contact urticaria, asthma, rhinitis, and anaphylaxis have only occasionally been described and are considered to be rare. Interestingly, some metals are able to cause both type I and type IV hypersensitivity reactions (Table 25.1). In this chapter, we will review contact urticaria reactions to nickel, chromium, aluminum, iridium, platinum, and cobalt. Other metals that can induce asthma will only be discussed briefly. Metals Capable of Inducing Urticaria and Hypersensitivity Reactions https://www.niso.org/standards/z39-96/ns/oasis-exchange/table">
Metal
Type 1 Reactions (References)
Type 4 Reactions (References)
Nickel
Contact urticaria [2,3,7–11]
ACD [1,2]
Asthma [4,5,36,48–50]
Oral [51]
Rhinitis [6,37]
Chromium
Systemic urticaria [16]
ACD [1]
Asthma [33,35]
Anaphylaxis [16]
Iridium
Urticaria [27]
Oral [28] a
Rhinitis [27]
Asthma [27]
Platinum
Contact urticaria [17,19,24]
ACD [19]
Asthma [19,20]
Rhinitis [19]
Cobalt
Contact urticaria [32]
ACD [30]
Generalized urticaria [32]
Asthma [32]
Anaphylaxis [32]
The patients reacted to the patch test but did not have ACD.
Note: ACD = allergic contact dermatitis.