A case of severe methemoglobinemia caused by hair dye poisoning

Abstract

Hair dyes are widely used and very popular xenobiotics. Most of these products contain paraphenylenediamine (PPD) that can cause methemoglobinemia. We here report a case of severe methemoglobinemia that we treated using large amounts of methylene blue. A 30-year-old man visited a regional hospital with cyanosis. He was congenitally blind and had autism. For several weeks, he had mistaken hair dye for toothpaste. When he arrived at a regional hospital, he was drowsy with cyanosis and his initial serum methemoglobin (MetHb) level was 59.5%. After being treated with 2 mg/kg methylene blue (1 mg/kg × 2 administrations), he was transferred to a tertiary university hospital. Upon presentation at the Emergency Department in the tertiary hospital, his MetHb level was found to be 49.4% and his oxygen saturation was 80%. He was then admitted to the intensive care unit. After treatment with 4 mg/kg methylene blue (1 mg/kg × 4 administrations), he successfully recovered. Because PPD can result in serious methemoglobinemia, clinicians should test it in cyanotic patients who have been exposed to hair dye for an extended period.