Paeds · haematology-oncology-and-transfusion
Iron deficiency anaemia
Also known as Iron deficiency anaemia · Iron deficiency · Microcytic anaemia · Cow's milk anaemia · Nutritional anaemia
Fellowship guide to iron deficiency anaemia in children, beginning with the dietary and growth-driven demand that outstrips supply in toddlers and adolescent girls, the microcytic hypochromic blood film with a low ferritin, the WHO age-banded haemoglobin thresholds, the hepcidin-ferroportin axis that traps iron in inflammation, the Mentzer index that splits iron deficiency from thalassaemia trait, oral elemental iron at 3 to 6 mg per kg per day given once daily or on alternate days for at least three months, the reticulocyte response by day 7 to 10 and haemoglobin rise of about 10 g per litre per week, intravenous iron when oral fails, restrictive transfusion for the severely compromised child, the cow's milk history, the refractory case that demands coeliac serology and a search for occult blood loss, and the neurodevelopmental harm of iron deficiency in infancy.
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- A child with severe anaemia and tachycardia, a gallop, hepatomegaly or respiratory distress has cardiovascular compromise and may need a cautious, slow transfusion rather than oral iron alone — fluid overload in a hypoxic, anaemic heart can precipitate pulmonary oedema
- Iron deficiency anaemia that fails to correct after four weeks of compliant oral iron is refractory — re-check adherence, send coeliac serology, look for ongoing occult blood loss, and reconsider the diagnosis, because thalassaemia trait and anaemia of chronic disease will not respond to iron
- Iron deficiency in a child over three years or in any boy without menorrhagia is unusual from diet alone — pursue gastrointestinal blood loss from inflammatory bowel disease, a Meckel diverticulum, polyps or, in endemic regions, hookworm
- Do not give parenteral iron to a child with an active infection without weighing the risk, because iron feeds pathogens and the hepcidin-driven iron sequestration is partly a host defence
- Pica, especially pagophagia (compulsive ice eating), is a striking and specific clue to iron deficiency — ask for it directly, because families rarely volunteer it
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- Definition and WHO age-banded haemoglobin thresholds for anaemia in children
- Dietary causes of iron deficiency in toddlers: excessive cow's milk, early weaning, prematurity
- Oral elemental iron at 3 to 6 mg per kg per day for at least three months
- Hepcidin-ferroportin axis and functional iron deficiency in inflammation
- Refractory iron deficiency anaemia: coeliac disease, occult blood loss, malabsorption
- Alternate-day oral iron dosing and intravenous iron in children
- Investigation of microcytic anaemia: ferritin, iron studies, Mentzer index
- Distinguishing iron deficiency from thalassaemia trait and anaemia of chronic disease
- Response to iron: reticulocytes at 7 to 10 days, haemoglobin rise of 10 g per litre per week
- Short case: a pale toddler with a heart murmur and microcytic anaemia
- Long case: an adolescent girl with menorrhagia, fatigue and iron deficiency
- Communication: dietary counselling and iron therapy for a family
- Haematology and oncology: iron deficiency anaemia in children
- Nutrition: iron requirements and the prevention of deficiency
- Gastroenterology: coeliac disease as a cause of refractory iron deficiency
- Iron metabolism, hepcidin and the causes of iron deficiency
- Interpretation of ferritin and iron studies in the presence of inflammation
- Pharmacology of oral and intravenous iron preparations
- Assessment of the pale child and the workup of microcytic anaemia
- Communication: explaining iron deficiency, diet and treatment to a family
- Iron deficiency anaemia: causes, evaluation and management
- Screening for anaemia and the AAP universal haemoglobin at 12 months
- Dietary prevention and iron supplementation in infancy
- Patient Care: evaluation and management of the child with iron deficiency anaemia
- Medical Knowledge: iron homeostasis and the differential of microcytic anaemia
- Systems-Based Practice: screening, nutrition and health equity in iron deficiency
- Haematology: iron deficiency anaemia in infants and children
- Investigation of microcytic anaemia and refractory iron deficiency
- Oral and intravenous iron therapy and preventive strategies
The discipline of this topic is that the diagnosis is easy to make and easy to miss for the same reason: every microcytic anaemia looks alike on the full blood count. The ferritin is the gatekeeper, but ferritin is an acute-phase reactant, so a normal ferritin in a sick or inflamed child does not exclude iron deficiency. [1] [7] This page owns the diagnostic fork for the microcytic anaemias, the hepcidin-driven mechanism that traps iron, the age-banded thresholds, the oral iron regimen, the intravenous and transfusion pathways for the severe case, and the refractory workup. The companion anaemia diagnostic approach page carries the broader differential.
The teaching spine is four questions. First, is it iron deficiency — low ferritin, low transferrin saturation, raised soluble transferrin receptor? Second, why — what is demanding or losing the iron? Third, will oral iron work, or does this child need intravenous iron or a transfusion? Fourth, will it correct — and if not, what is being missed? [2] [3]
Overview & Definition
Iron deficiency anaemia is the anaemia that results when the body's iron stores fall too low to sustain normal haemoglobin synthesis, producing small, pale, under-haemoglobinised red cells. The World Health Organization defines anaemia in children by age-banded haemoglobin thresholds: below 110 g per litre from 6 to 59 months, below 115 g per litre from 5 to 11 years, and below 120 g per litre from 12 to 14 years. [1] [3] Iron deficiency is the commonest cause across all these ages, and it exists on a spectrum from depleted stores without anaemia through to frank, symptomatic disease.
The distinction between iron deficiency and iron deficiency anaemia matters clinically and in counselling. A child can be iron-deficient — low ferritin, raised soluble transferrin receptor, no anaemia yet — and already be experiencing the non-haematological effects of deficiency, including fatigue, poor concentration and, in infancy, developmental concern. [11] [2] Anaemia is the late, haematological end of the same process. This is why the workup uses ferritin and iron studies, not the haemoglobin alone, and why the treatment repletes stores rather than merely lifting the haemoglobin into range.
Iron is in constant demand for growth, for the expanding red-cell mass, and to replace the small obligate losses through skin desquamation and, in menstruating adolescents, menstrual blood. A child needs to absorb about 1 mg of iron per day against the 90 percent of dietary iron that is normally lost, so the margin for a poor diet or increased loss is thin. [1] [5] When intake or absorption cannot keep up with demand, the stores empty first, the transport iron falls next, and the haemoglobin drops last.
References12ShowHide
- [1]Lopez A; Cacoub P; Macdougall IC; Peyrin-Biroulet L Iron deficiency anaemia. Lancet, 2016.PMID 26314490
- [2]Camaschella C Iron deficiency. Blood, 2019.PMID 30401704
- [3]Mattiello V; Schmugge M; Hengartner H; von der Weid N; Renella R; SPOG Pediatric Hematology Working Group Diagnosis and management of iron deficiency in children with or without anemia: consensus recommendations of the SPOG Pediatric Hematology Working Group. Eur J Pediatr, 2020.PMID 32020331
- [4]Leung AKC; Lam JM; Wong AHC; Hon KL; Li X Iron Deficiency Anemia: An Updated Review. Curr Pediatr Rev, 2024.PMID 37497686
- [5]Wang M Iron Deficiency and Other Types of Anemia in Infants and Children. Am Fam Physician, 2016.PMID 26926814
- [6]Cappellini MD; Musallam KM; Taher AT Iron deficiency anaemia revisited. J Intern Med, 2020.PMID 31665543
- [7]Cappellini MD; Comin-Colet J; de Francisco A; Dignass A; Doehner W; Lam CS; Macdougall IC; Rogler G; Camaschella C; Kadir R; Kassebaum NJ; Spahn DR; Taher AT; Musallam KM; IRON CORE Group Iron deficiency across chronic inflammatory conditions: International expert opinion on definition, diagnosis, and management. Am J Hematol, 2017.PMID 28612425
- [8]Stoffel NU; Cercamondi CI; Brittenham G; Zeder C; Geurts-Moespot AJ; Swinkels DW; Moretti D; Zimmermann MB Iron absorption from oral iron supplements given on consecutive versus alternate days and as single morning doses versus twice-daily split dosing in iron-depleted women: two open-label, randomised controlled trials. Lancet Haematol, 2017.PMID 29032957
- [9]Stoffel NU; Zeder C; Brittenham GM; Moretti D; Zimmermann MB Iron absorption from supplements is greater with alternate day than with consecutive day dosing in iron-deficient anemic women. Haematologica, 2020.PMID 31413088
- [10]Pasricha SR; Hasan MI; Braat S; Larson LM; Tipu SMM; Hossain SJ; Shiraji S; Baldi A; Bhuiyan MSA; Tofail F; Fisher J; Grantham-McGregor S; Simpson JA; Hamadani JD; Biggs BA Benefits and Risks of Iron Interventions in Infants in Rural Bangladesh. N Engl J Med, 2021.PMID 34496174
- [11]Larson LM; Phiri KS; Pasricha SR Iron and Cognitive Development: What Is the Evidence? Ann Nutr Metab, 2017.PMID 29268256
- [12]Low M; Farrell A; Biggs BA; Pasricha SR Effects of daily iron supplementation in primary-school-aged children: systematic review and meta-analysis of randomized controlled trials. CMAJ, 2013.PMID 24130243