Introduction
Cobalt is an essential element to humans in the form of cobalamin (vitamin B12). The human body contains approximately 1 mg of cobalt, which around eighty percent is a component of vitamin B12. Human dietary intake of inorganic cobalt including green leafy vegetables, dairy products, liver and cereal grains varies between 5 and 50 μg/day, while vitamin B12 represents cobalt only in minute amounts. Cobalt does not accumulate in the body and is rapidly excreted in urine. (1, 2)
We report a case of systemic pigmented contact dermatitis, presenting as hyperpigmented lesions on face, neck and upper back caused by ingesting cobalt (cobalamin, vitamin B12). This patient had a history of ingesting cobalamin (vitamin B12) to treat her neuropathic pain 2 years earlier.