Metal Allergy

There are two types of metal allergies: contact allergies and systemic metal allergies. Metal contact allergy is a delayed-type (type IV) hypersensitivity reaction in which T cells play an important role. Nickel allergy is the most common type of allergy. Patch testing is a standard method for treating skin metal allergies (contact dermatitis). A patch test alone is not sufficient for diagnosing systemic metal allergy, and the test is controversial for hypersensitivity to implants and is not suitable for the diagnosis of metal allergy to artificial joints; however, accurate diagnostic methods for metal allergy after arthroplasties have not been established. The lymphocyte stimulation test is commonly used for metal allergies to artificial joints.