Anemia in Children

Anemia in Children: When Is It Just Iron Deficiency, and When Does It Need Further Evaluation?

Anemia is one of the most common hematologic problems in childhood. In many children, particularly infants and adolescents, iron deficiency is an important and treatable cause. However, not every child with anemia has iron deficiency.

Anemia can result from inadequate iron intake, blood loss, inherited disorders, destruction of red blood cells, chronic inflammation, nutritional deficiencies, or disorders affecting the bone marrow. For this reason, the correct approach is not simply to prescribe iron whenever a child's hemoglobin is low. The first step is to understand why the child is anemic.

The American Academy of Pediatrics published an updated clinical report in 2026 addressing prevention, screening, diagnosis, and treatment of iron deficiency and iron-deficiency anemia from infancy through adolescence. The recommendations emphasize clinical risk factors, appropriate laboratory evaluation, and reassessment of children who have recurrent or treatment-resistant anemia.

What is anemia in children?

Anemia occurs when the hemoglobin concentration is lower than expected for a child's age and physiologic characteristics. Hemoglobin is the protein in red blood cells responsible for carrying oxygen to tissues. Because normal hemoglobin values change throughout childhood, anemia should always be interpreted using age-appropriate reference ranges rather than a single universal cutoff.

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Why Is Iron Important?

Iron is essential for hemoglobin production, cellular metabolism, and normal neurodevelopment. Iron deficiency can occur before anemia develops. This is particularly important during infancy and adolescence, when iron requirements are increased. Iron deficiency has also been associated with impaired neurocognitive development.

Risk factors include:

• Inadequate dietary iron;
• Excessive milk intake in young children;
• Restricted diets;
• Malabsorption;
• Chronic blood loss;
• Heavy menstrual bleeding in adolescents; and
• Increased requirements during periods of rapid growth.

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What causes anemia in a child?

Anemia has three main causes:

• Loss of red blood cells
• Inability to make enough red blood cells
• Destruction of red blood cells

Decreased red blood cells or hemoglobin levels may be due to:

• Inherited red blood cell defects
• Infections
• Some diseases
• Certain medicines
• Lack of some vitamins or minerals in the diet

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Which children are at risk for anemia?

Risk factors for anemia include:

• Premature or low birth weight
• Living in poverty or immigrating from developing country
• Too much cow’s milk
• Diet low in iron, or some vitamins or minerals
• Surgery or accident with blood loss
• Long-term illnesses, such as infections, or kidney or liver disease
• Family history of an inherited type of anemia, such as sickle cell anemia

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What are the symptoms of anemia in a child?

Most symptoms of anemia are due to the lack of oxygen in the cells. Many of the symptoms don't occur with mild anemia.

These are the most common symptoms:

• Increased heart rate
• Breathlessness, or trouble catching a breath
• Lack of energy, or tiring easily
• Dizziness, or vertigo, especially when standing
• Headache
• Irritability
• Irregular menstrual cycles
• Absent or delayed menstruation
• Sore or swollen tongue
• Pale skin
• Yellowing of skin, eyes, and mouth (jaundice)
• Enlarged spleen or liver
• Slow or delayed growth and development
• Poor wound and tissue healing

Many of these symptoms may be caused by other blood problems or health conditions. Anemia is often a symptom of another disease. Report any symptoms to your child’s healthcare provider. Always see your child's provider for a diagnosis.

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How is anemia diagnosed in a child?

A complete blood count provides much more information than hemoglobin alone.

The pediatrician or hematologist may evaluate:

• Hemoglobin and hematocrit;
• MCV and MCH;
• RDW;
• Reticulocyte count;
• White blood cell count;
• Platelet count; and
• Peripheral blood smear.

These findings help classify anemia as microcytic, normocytic, or macrocytic and provide important clues about its underlying mechanism.

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Why Is the Reticulocyte Count Important?

Reticulocytes are newly produced red blood cells. The reticulocyte count helps determine whether the bone marrow is responding appropriately to anemia. A high reticulocyte response may occur when red blood cells are being destroyed or lost and the bone marrow is compensating. A low or inappropriately normal response may suggest inadequate red-cell production. This distinction can significantly narrow the differential diagnosis.

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How Is Iron Deficiency Diagnosed?

Depending on the clinical situation, evaluation may include:

• Serum ferritin;
• Serum iron;
• Transferrin or total iron-binding capacity;
• Transferrin saturation;
• Reticulocyte hemoglobin content when available;
• CBC and red-cell indices; and
• Markers of inflammation.

Ferritin reflects iron stores but can increase during inflammation. Therefore, iron studies should be interpreted together with the child's clinical history and other laboratory findings. The 2026 AAP report emphasizes using clinical risk factors and appropriate laboratory testing rather than relying on a single laboratory value.

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When Is an Iron Trial Reasonable?

When the clinical picture strongly suggests iron deficiency, oral iron therapy may be appropriate.

However, the child's response should be monitored.

1. If the hemoglobin does not improve as expected, it is important to reassess:
2. Was the diagnosis correct?
3. Was the medication taken consistently?
4. Was the dose appropriate?
5. Is there ongoing blood loss?
6. Is there malabsorption?
7. Could the child have thalassemia or another hematologic disorder?

Failure to respond appropriately should therefore lead to reassessment rather than indefinite continuation of iron therapy.

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Heavy Menstrual Bleeding in Adolescents

Heavy menstrual bleeding is an important and sometimes overlooked cause of iron deficiency in adolescents.

Warning features include:

• Prolonged or very heavy menstrual periods;
• Frequent pad or tampon changes;
• Large blood clots;
• Bleeding through clothing or bedding;
• Symptoms of anemia; or
• A personal or family history of abnormal bleeding.

Iron deficiency may result from menstrual blood loss, but heavy menstrual bleeding can also be the first manifestation of an inherited bleeding disorder such as von Willebrand disease. A hematologic evaluation may therefore be necessary.

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When Should We Think Beyond Iron Deficiency?

Further evaluation is particularly important when:

• Anemia is severe or persistent;
• Anemia recurs after treatment;
• There is no appropriate response to iron therapy;
• Significant bleeding is present;
• Other blood-cell lines are abnormal;
• The peripheral smear is abnormal;
• There is jaundice or evidence of hemolysis;
• Microcytosis persists despite normal iron stores;
• There is a family history of anemia or hemoglobinopathy;
• Systemic symptoms such as fever, weight loss, bone pain, or lymphadenopathy are present.

Anemia accompanied by abnormalities in white blood cells or platelets deserves particular attention because it may indicate a broader bone marrow disorder.

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Anemia Does Not Automatically Mean Cancer

This is an important message for parents. Most children with anemia do not have leukemia or another cancer. Iron deficiency, inherited hemoglobin disorders, blood loss, and other conditions are much more common explanations. However, pediatric hematology is not simply about identifying cancer. It is about accurately determining the cause of an abnormal blood count and ensuring that children receive the appropriate treatment.

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When Should You See a Pediatric Hematologist?

Specialist evaluation may be appropriate for children with:

• Unexplained or persistent anemia;
• Severe or recurrent anemia;
• Anemia that does not respond appropriately to iron therapy;
• Persistent microcytosis despite adequate iron stores;
• Suspected thalassemia or another hemoglobin disorder;
• Abnormal bleeding or bruising;
• Heavy menstrual bleeding;
• Persistent thrombocytopenia or neutropenia;
• Multiple abnormal blood-cell lines; or
• A family history suggesting an inherited blood disorder.

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The Bottom Line: If your child has been diagnosed with anemia, the most important question is not simply: “Which iron supplement should we give?”

It is: “Why is my child anemic?” For many children, the answer will be iron deficiency, which is usually treatable. But severe, persistent, recurrent, or unexplained anemia deserves a more detailed evaluation.

Early assessment can establish the correct diagnosis, prevent unnecessary treatment, and identify children who require specialist care.

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References

1. Powers JM, Heeney MM, Hord J, et al. Prevention, Screening, Diagnosis, and Treatment of Iron Deficiency and Iron Deficiency Anemia in Infants, Children, and Adolescents: Clinical Report. Pediatrics. 2026;158(1):e2026077414.
2. Baker RD, Greer FR; Committee on Nutrition, American Academy of Pediatrics. Diagnosis and prevention of iron deficiency and iron-deficiency anemia in infants and young children. Pediatrics. 2010;126(5):1040–1050.
3. Georgieff MK. Iron assessment to protect the developing brain. Am J Clin Nutr. 2017;106(Suppl 6):1588S–1593S.
4. Lanzkowsky P, Lipton JM, Fish JD. Lanzkowsky's Manual of Pediatric Hematology and Oncology. 7th ed. Elsevier.

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