Nickel is contained in many objects that may come into contact with the skin: metal clothing accessories, glass frames, bijouterie, coins, keys, tableware and others.
Nickel is also contained in most foods of plant origin. In particular, those with the highest content are nuts, chocolate, tomatoes and legumes.
Nickel can cause both eczematous skin manifestations such as Allergic Contact Dermatitis (ACD) and clinical pictures with systemic involvement, such as urticaria, angioedema, erythema, gastrointestinal disorders, called Systemic Nickel Allergy Syndrome (SNAS).