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.