Alergic contact dermatitis is one of the most frequent skin disorders, with still increasing prevalence also in children. Predisposing factors are genetic factors, environment conditions, atopy and smoking cigarettes. Metal ions are most frequent allergens. Among them most important is nickel, because of its often and easy contact in metal jewellery. Increasing incidence of sensitivity is caused by popular habit of piercing body. Nickel is also allergen of occupational skin sensitivity. Nowadays allergy to nickel is a problem in dentistry and prosthetics. In Europe legislation regulate contains of nickel ions in everyday used objects.

Next important contact allergen is chromium, previously very frequent among construction workers. Actually is still present as a cause of “shoe dermatitis”. The last one of the most essential metals is cobalt. Sensitivity to cobalt is associated with allergy to other metals.