aniline have been reported to cause cyclic or rebound methemoglobinemia Consultation with toxicology or poison control is advised INEFFECTIVE OR DECREASED RED BLOOD CELL PRODUCTION CLINICAL PEARLS AND PITFALLS Decreased RBC production may be due to congenital abnormalities (e.g., Diamond–Blackfan anemia [DBA]), marrow infiltrative processes (e.g., malignancy, fibrosis, lysosomal storage disease), or acquired insults (e.g., viral suppression, toxins, nutritional deficiency) β-Thalassemia major usually presents only after to months of age with the switch from γ- to β-globin chain production; it may present with severe anemia causing a hematologic emergency Iron replacement therapy for iron-deficiency anemia consists of to mg/kg/day of elemental iron given orally as ferrous sulfate at night on an empty stomach (and ideally with ascorbic acid) as a single daily dose IV or SQ formulations not provide a clinical advantage in the absence of malabsorption The goal of transfusion for chronic, severe anemia is relief of symptoms, not restoration of a normal hemoglobin level If transfusion is necessary, provide small aliquots of RBCs (5 mL/kg) slowly with close monitoring and consideration of furosemide administration Current Evidence Thalassemia The thalassemias are mutations or deletions of the globin genes that result in reduced or loss of production of α- or β-globin chains, the building blocks of hemoglobin Hemoglobin A (normal adult hemoglobin α2β2) begins rising just prior to birth as the body switches production from γ- to β-globin chains, and increases steadily over the first year of life to become the predominant hemoglobin The β-thalassemia gene mutations occur most commonly in populations living in regions bordering the Mediterranean, North Africa, the Middle East, Central and Southeast Asia, and India In β-thalassemia, reduced (β+ ) or no (β0) β-globin chains are produced β-Thalassemia major phenotype results from β0/β0 or β0/β+ , intermedia phenotype from β+ /β+ , and carrier state from β/β+ In the first year of life, infants with β-thalassemia major usually develop a sallow complexion, increased fatigue, and poor weight gain and linear growth Physical examination shows pallor, icterus, and enlargement of the liver and spleen In thalassemia major, the hemoglobin level may decrease to or g/dL, and the mean