Anaemia is defined as a low concentration of haemoglobin in the blood. This is the consequence of an underlying disease, not a disease itself. An- means without, and -aemia refers to blood.
Haemoglobin is a protein found in red blood cells. Haemoglobin is responsible for picking up oxygen in the lungs and transporting it to the body’s cells. Iron is essential in producing haemoglobin and forms part of its structure.
The normal ranges for haemoglobin in a child are determined by the local haematology lab, depending on their age.
| Age | Haemoglobin (g/L) |
| Birth | 140-240 |
| 1-2 months | 90-140 |
| 6 months – 6 years | 110-140 |
| 6 – 12 years | 115-155 |
| Female ≥12 years | 120-155 |
| Male ≥12 years | 130-170 |
Causes
The most common causes of anaemia in children are:
- Iron deficiency anaemia secondary to dietary insufficiency (most common overall)
- Blood loss (most frequently from menstruation in adolescent girls)
Less common causes of anaemia in children include:
- Sickle cell disease
- Thalassaemia
- Leukaemia
- Hereditary spherocytosis
- Hereditary elliptocytosis
- Sideroblastic anaemia
- Anaemia of chronic disease
Worldwide, a common cause of blood loss causing chronic anaemia and iron deficiency is helminth infection, particularly with hookworms. This is common in low and middle-income settings. It is less common in the UK. Treatment is with a single dose of albendazole or mebendazole.
Symptoms
Mild anaemia may be asymptomatic. Generic symptoms of anaemia are non-specific:
- Tiredness
- Dizziness
- Palpitations
- Headaches
Symptoms specific to iron deficiency anaemia include:
- Pica (dietary cravings for abnormal things, such as dirt, soil, paper or soap)
- Hair loss
Signs
Generic signs of anaemia include:
- Pale skin
- Conjunctival pallor
- Tachycardia (raised heart rate)
Signs of specific causes of anaemia include:
- Koilonychia refers to spoon-shaped nails and can indicate iron deficiency anaemia
- Angular cheilitis can indicate iron deficiency anaemia
- Atrophic glossitis is a smooth tongue due to atrophy of the papillae and can indicate iron deficiency anaemia
- Brittle hair and nails can indicate iron deficiency anaemia
- Jaundice can indicate haemolytic anaemia
- Bone deformities can occur in severe thalassaemia
Investigating Anaemia
Blood tests for anaemia include:
- Full blood count for haemoglobin and mean corpuscular volume
- Reticulocyte count (indicates red blood cell production)
- Blood film for abnormal cells and inclusions
Reticulocytes are immature red blood cells. Raised reticulocytes indicate active production of red blood cells to replace lost cells (e.g., in haemolysis or blood loss). Low reticulocytes suggest reduced production (e.g., iron deficiency or leukaemia).
Blood tests for the underlying cause (depending on clinical features) include:
- Renal profile
- Liver function tests for liver disease and bilirubin (raised in haemolysis)
- Ferritin (low in iron deficiency, but may be raised with inflammation)
- B12 and folate
- Thyroid function tests for hypothyroidism
- Coeliac disease serology (e.g., anti-tissue transglutaminase antibodies)
- Haemoglobin electrophoresis for thalassaemia and sickle cell disease
- Direct antiglobulin test (DAT) for autoimmune haemolytic anaemia
Further investigation will depend on the suspected underlying cause.
Management
Management depends on establishing the underlying cause and directing treatment accordingly. For example, iron deficiency can be treated with iron supplements. Severe anaemia may require blood transfusions.
Last updated March 2026
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