The co‐occurrence of acute hemolysis and methemoglobinemia secondary to favism in G6PD deficient individuals is rare. Identifying it promptly is of high clinical significance as treating methemoglobinemia (with methylene blue) can worsen hemolysis.

We report a 56-year-old man with methemoglobinemia and hemolytic anemia, secondary to fava bean ingestion. Methylene blue administration worsened the hemolysis as he was G6PD deficient but not diagnosed before. We have discussed the mechanism of hemolysis in such patients and the management of such cases.Hemolytic anemia, a form of anemia that causes premature rupture of erythrocytes, accounts for five percent of anemias. 1 Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a well-known cause of hemolysis and currently affects around 400 000 000 individuals globally. It has a notable prevalence in African, Asian, and Mediterranean countries. 2 Favism is a common trigger of oxidative stress in G6PD deficient people, which can lead to hemolysis. Additionally, fava bean ingestion can cause methemoglobinemia. 3 Methemoglobin is an abnormal variation in the hemoglobin in which the ferrous (Fe2 + ) iron in heme is oxidized to the ferric (Fe3 + ) state. The condition is usually acquired, secondary to oxidative stress in the body such as favism or infections, but can rarely be congenital. 4 The first-line treatment for methemoglobinemia is methylene blue. However, in G6PD deficient patients, methylene blue can potentiate hemolysis because of its oxidative effects. 3 It is vital to take a detailed history of patients presenting with hemolysis to identify the potential causes and avoid any additional oxidative stress.

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Mast cells are found in bone marrow, blood, mucosal, and connective tissues. They migrate into the loose connective tissue of all organs. They play a major role in many physiologic processes however as discussed in this article they can become an aggressive force which can damage the natural biological balance