Summary
Iron-deficiency anemia is the most common nutritional deficiency in young children and matters beyond the hematologic picture because iron is required for normal neurodevelopment during the same window [1][2]. It remains common in the United States, and its prevalence in toddlers has been documented across recent decades, including current estimates [4][5].
- Iron deficiency and iron-deficiency anemia are a spectrum. Iron stores fall first, then transport iron, and anemia is the late finding, so a normal hemoglobin does not exclude deficiency [2][3].
- Universal screening for anemia is recommended around 12 months of age, paired with an assessment of dietary and social risk factors [1].
- The typical picture is a microcytic, hypochromic anemia in a toddler with a history of excessive cow's milk intake or prolonged exclusive breastfeeding without iron supplementation [1][2].
- A therapeutic trial of oral iron is a reasonable first step in a well child with a compatible history. The guideline defines a hemoglobin increase of at least 1 g/dL after one month of supplementation as confirming iron-deficiency anemia [1].
Caution. Not every microcytic anemia is iron deficiency. Thalassemia trait produces microcytosis with a normal or high red cell count and a disproportionately low mean corpuscular volume for the degree of anemia. Screen appropriately by ancestry and family history before committing a child to prolonged iron therapy, and reassess if the hemoglobin does not respond [2].
Diagnosis
Screening begins with hemoglobin, and abnormal values are then characterized with iron studies [1]. Ferritin is the most useful single marker of iron stores but rises with inflammation, so interpret a normal ferritin cautiously in an acutely ill child [2][3].
| Marker |
Pattern in iron deficiency |
Caveat |
| Hemoglobin |
Low, late finding |
Normal despite depleted stores early [2][3] |
| Mean corpuscular volume |
Low (microcytic) |
Also low in thalassemia trait [2] |
| Ferritin |
Low |
Falsely normal or high with inflammation [2][3] |
| Reticulocyte response |
Rises after iron started |
Supports a therapeutic trial |
The reticulocyte response to iron confirms the diagnosis when it is uncertain. A rising corrected reticulocyte count within a week or two of starting iron supports iron deficiency as the cause.
Correct the reticulocyte count for the degree of anemia in Corrected Reticulocyte →
When the count is drawn with a concurrent leukocytosis or nucleated red cells, correct the white cell count so the differential is not misread.
Adjust the white count for nucleated red cells in Corrected WBC →
In a child on chemotherapy or with a suppressed marrow, the absolute neutrophil count frames the infection risk that accompanies any cytopenia.
Calculate the absolute neutrophil count in ANC →
Management
Oral iron is first-line, given as elemental iron at a commonly used 3 to 6 mg per kilogram per day, and the guideline's benchmark of response is a hemoglobin rise of at least 1 g/dL after one month of therapy [1]. Once-daily dosing, sometimes on alternate days, is often as effective as divided dosing and is better tolerated, since large frequent doses raise hepcidin and limit further absorption [2].
Address the underlying cause alongside supplementation. Limit cow's milk, which displaces iron-rich foods and can cause occult gastrointestinal blood loss in the youngest children, and increase dietary iron [1][2]. Standard practice is to continue iron for two to three months after the hemoglobin normalizes to replete stores, and to confirm the response rather than assuming it.
Reserve intravenous iron and further hematologic evaluation for children who cannot tolerate or do not respond to oral iron, or in whom the initial assumption of simple dietary deficiency proves wrong [2].
References
- Baker RD, Greer FR; Committee on Nutrition. Diagnosis and prevention of iron deficiency and iron-deficiency anemia in infants and young children (0-3 years of age). Pediatrics. 2010;126(5):1040-1050. doi:10.1542/peds.2010-2576
- Camaschella C. Iron-deficiency anemia. N Engl J Med. 2015;372(19):1832-1843. doi:10.1056/NEJMra1401038
- Lopez A, Cacoub P, Macdougall IC, Peyrin-Biroulet L. Iron deficiency anaemia. Lancet. 2016;387(10021):907-916. doi:10.1016/S0140-6736(15)60865-0
- Brotanek JM, Gosz J, Weitzman M, Flores G. Secular trends in the prevalence of iron deficiency among US toddlers, 1976-2002. Arch Pediatr Adolesc Med. 2008;162(4):374-381. doi:10.1001/archpedi.162.4.374
- Weyand AC, McGann PT, et al. Prevalence of iron deficiency and iron deficiency anemia in US children. Am J Hematol. 2026. doi:10.1002/ajh.70207