People with type 1 methemoglobinemia and hemoglobin M disease usually do well. Type 2 methemoglobinemia is much more serious, and usually causes death within the first few years of life.
People with acquired methemoglobinemia usually do very well once the drug, food, or chemical that caused the problem is identified and avoided.
What to expect if I have Methemoglobinemia  (Outlook/Prognosis)?
People with type 1 methemoglobinemia and hemoglobin M disease usually do well. Type 2 methemoglobinemia is much more serious, and usually causes death within the first few years of life.
People with acquired methemoglobinemia usually do very well once the drug, food, or chemical that caused the problem is identified and avoided.