Methemoglobinemia (blue people): symptoms, causes and treatment

Our skin is an organ that is often undervalued and unrecognized, Which protects our body against many harmful elements such as bacteria, fungi and solar radiation.

This important part of our body, however, in addition to protecting us sometimes also warns us of the presence of alterations in other areas of our body which can have serious health implications. This is the case, for example, with jaundice, in which the skin acquires yellowish tones.

Another of the disorders in which abnormal coloring of the skin appears is methemoglobinemia, an alteration of the blood origin in which the skin becomes bluish and depending on its type can have fatal consequences.

    Methemoglobinemia: what it is and symptoms

    We call metahemoglobinemia a strange blood disorder characterized by the presence of an excessive level of a subtype of hemoglobin called metahemoglobin. This particular type of hemoglobin does not have the ability to carry oxygen, And at the same time interferes with hemoglobin, which is able to do so in such a way that the latter cannot release it normally in different organs and tissues. This reduces the oxygenation of the body.

    One of its most obvious and easily visible symptoms of this disorder is cyanosis, or blue discoloration of the skin (although the tones may vary, it is usually an intense bluish color). This is probably due to the aforementioned decrease in oxygenation of the body.. And not just the skin: the blood also changes color, losing its characteristic red as it turns brown.

    However, discoloration of the skin is not the only problem that can arise: if the excess of methemoglobin is too much, the lack of oxygen in the rest of the body can lead to organ problems and even death. It is not uncommon for breathing problems to appear as well, which is usually one of the main causes of hospitalization.

    In addition to the above, depending on the type of methemoglobinemia we may experience headaches, fatigue, seizures and breathing problems with fatal potential (in the case of acquired causes) or the appearance of an intellectual disability and delays in maturation in the case of congenital methemoglobinemia type 2 which we will discuss later.

      Typologies according to their causes

      The causes of the appearance of this disorder can be multiple and can appear both congenital and acquired.

      Acquired metahemoglobinemia is the most common and usually occurs derived from consumption or exposure to oxidizing drugs or chemicals such as bismuth nitrate, as well as items used to treat certain illnesses such as nitroglycerin or certain antibiotics.

      As for congenital methemoglobinemia, it is generally due to gene transmission or the appearance of certain mutations. We can find two basic types.

      The first of these is generated by genetic inheritance from both parents, both parents carrying (although most did not express the disorder) a mutation in certain genes that causes a problem with the enzyme citrochrome b5 reductase. This enzyme does not work properly in the body, causing oxidation of hemoglobin.

      In this type of congenital methemoglobinemia we can find two main types: congenital methemoglobinemia type 1 is that the aforementioned enzyme does not appear in the red blood cells of the body and type 1 in which the enzyme does not appear directly instead of the body.

      The other option in congenital metahemoglobinemias is the so-called hemoglobin M disease, in which this alteration appears because the hemoglobin is structurally altered at the base. In these cases we are faced an autosomal dominant disorder in which only one parent is a carrier of the gene and pass it on to generate the change (something similar to what happens with Huntington’s Korea).

      Treatment of this condition

      Although it may seem hard to believe, methemoglobinemia is a medical condition that has curative treatment in some cases.

      In most cases, the prognosis is positive and the patient can make a full recovery. The treatment is mainly to generate a reduction in methemoglobin levels and an increase in hemoglobin with oxygen carrying capacity, methylene blue injection (Except in patients at risk of G6PD deficiency, in which it may be dangerous) or other substances with a similar effect.

      If that doesn’t work, you can use hyperbaric chamber treatment. Vitamin C intake can also be helpful, although its effect is less.

      In the case of acquired methemoglobinemia, removal of the substance that caused the deterioration is also required. Mild cases may not require more than that, but in people with breathing or heart problems if the treatment described above is needed.

      The changes with these treatments can be dramatic, High speed change in skin color.

      However, in the case of congenital methemoglobinemia type 2 the disease is much more complicated and its prognosis much more serious, being common in the death of the minor during the first years.

      Bibliographical references:

      • Hoffman R, Benz EJ Jr, Silberstein LE, Heslop HE, Weitz JI, Anastasi J, eds. Hematology: basic principles and practice. 6th ed. Philadelphia, PA: Elsevier Saunders; 2013: Chapter 41. Available at:
      • Goldfrank, R. L, (2006). Goldfrank toxicological emergencies. 8th. Editing. New York. UNITED STATES.
      • Roman, L. (2011). 18-year-old woman with methemoglobinemia after using topical anesthetic cream. Journal of the Clinical Laboratory, 4 (1) .: 45-49.

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