Association of Methylmalonic Acidemia and Erythema Nodosum

Methylmalonic acidemia, one of the organic acidemias, is associated with a variety of clinical presentations ranging from very sick newborn infants to asymptomatic adults, regardless of the nature of the enzymatic defect or the biochemical abnormalities.1 A 6-year-old boy with a past history of methylmalonic acidemia presented to the emergency room with a one-week history of inflammatory nodular lesions on the anterior aspects of his legs. He had been on sodium bicarbonate, carnitine, vitamins B6 and B12, and biotin for a period of about 5 years. In physical examination, there was no fever, no lymphadenopathy or sign of arthritis. There were multiple erythematous tender nodules (3-6 cm) in diameter on both legs especially on the right one. In repeated examinations within the next 3 days the nodules became darker, harder and tenser and were still extremely tender to touch (figure 1).