A common clinical manifestation of metal allergy is allergic contact dermatitis, however, there are some other exceptional manifestations such as lichen planus, pustulosis palmaris et plantaris including dyshidrotic eczema and severe form of alopecia areata. Evidence for such exceptional cases are: reproducible positive patch test reactions to various metal ions; analytical results of dental metal testing demonstrating the presence of metals to which the patients are undoubtedly hypersensitive; and dramatic curative effects of allergenic metal elimination. These dental metals are presumed to elute thus leading to the disease when they electrochemically turn to be a cathode. Cases which could not have been cured by antisymptomatic treatment but by allergen elimination are reported.