An allergy is a hypersensitive reaction to an allergen, or triggering agent. Allergens like pollen and dust cause hay-fever like allergy symptoms such as sneezing, running nose and watering eyes. Metal allergies do not typically cause these hay-fever type effects. Symptoms of metal allergies usually take the form of negative reaction on the skin due to physical contact with the metal allergen material.

Contact Dermatitis

Contact dermatitis symptoms can include:

• a skin rash
  
• itching
  
• redness
  
• blisters that may lead to dry
  
• scaly patches
  
• according to the University of Alabama at Birmingham Health System

Contact dermatitis symptoms will appear between six and 24 hours after exposure to a metal allergen, advises the UAB Health System. People who are highly sensitive to nickel may also exhibit allergic reaction symptoms when eating foods which contain nickel, like fish or chocolate. Removing the item creating the reaction usually relieves the allergic symptoms in short order, and hydrocortisone cream can help bring relief from itching while waiting for the symptoms to dissipate.

Copper and Mercury Allergies

While most allergy-causing contact with metals occurs on the surface of the body, metal can also be inserted in the body for medical purposes, including copper intrauterine devices for birth control, and amalgam metal fillings in dental cavities. While rare, each of these can cause allergy symptoms in some individuals. Italian doctors in 1985 reported a case study, published in English by the U.S. National Library of Medicine, of a woman who exhibited swelling and itchiness in her eyelids and around her mouth after having a copper IUD inserted. After a few months, she experienced symptoms of intense itching and rash all over her body during menstruation. Blood tests revealed the cause of these symptoms to be heightened sensitivity to copper. Dental fillings contain an amalgam, or mix of metals, including mercury. In a small number of people, these metals can cause localized allergy symptoms similar to a contact dermatitis, according to the American Dental Association 1.

Metal Implant Allergic Responses

Metal joint implants can cause allergic reactions in some recipients, according to Dr. Sam Nasser, writing at the OrthoSuperSite, the website of "Orthopedics Today" magazine. Symptoms of allergies to one or more of the metals contained in orthopedic implants include swelling, itching and rashes on the skin around the site of the implant. Some patients also report symptoms of fatigue and weakness. Most instances of allergic reaction have involved implants including nickel or cobalt. Other metals used in the manufacture of implants -- titanium, tantalum and zirconium -- have not been shown to create allergic symptoms. Ceramic or ceramic-coated metal implants are being developed to help alleviate the potential for metal allergy reactions in orthopedic implant patients.