How Does Nickel Cause Allergic Reactions?
Allergic reactions occur when the immune system reacts adversely to a foreign substance (antigen). Nickel induces a contact dermatitis, which is a Type IV delayed hypersensitivity immune response.[2] There are 2 phases to this process. The sensitization phase occurs the instant the allergen (nickel) enters the body and causes a response. The elicitation phase occurs after the body is re-exposed to the antigen (nickel) a second time which causes the appearance of the full clinical manifestations. The initial exposure usually does not elicit symptoms, but subsequent contact with the antigen is usually enough to cause a more visible reaction.
