Metahemoglobinemia has been described in cases with severe reactions which may require treatment with bicarbonate. Although the cause is unknown, it has been proposed that intestinal inflammation leads to diminished catalytic activity and increased nitrates.
En 35% existe metahemoglobinemia, estos niños tienen apariencia pálida grisácea, se ha descrito en casos en casos de reacciones severas, pudiendo requerir tratamiento con bicarbonato; sin embargo, se desconoce la causa, se propone que la inflamación intestinal determina la disminución de la actividad catalasa e incremento de los nitratos.