Cobalt is a shiny silvery metal known for its hardness, wear-resistance and ability to create hard metal.1, 2 The prevalence of allergic contact dermatitis to cobalt is 1%–4% among the general population and 4%–11% among dermatitis patients.1 Several occupational groups, such as healthcare workers, electronics, construction and hard metal industry workers, are especially exposed and affected.1, 3 We present a rare case of occupational allergic contact dermatitis to cobalt due to direct skin exposure to a metal nut.