Anaemia is a reduction in the number of red blood cells or their haemoglobin content, impairing oxygen delivery to tissues — causing fatigue, pallor, and breathlessness.
Anaemia is defined as a haemoglobin concentration below normal for age and sex: <130 g/L in adult men, <120 g/L in adult women (WHO). It results from reduced red blood cell (RBC) production, increased RBC destruction (haemolysis), or blood loss. The most common type globally is iron-deficiency anaemia — caused by inadequate dietary iron intake, chronic blood loss (menstruation, GI bleeding), malabsorption (coeliac disease), or increased demand (pregnancy).
Other important types include vitamin B12 and folate deficiency anaemia (megaloblastic — producing abnormally large RBCs), haemolytic anaemia (from thalassaemia, aplastic conditions, or autoimmune destruction), anaemia of chronic disease (from inflammatory conditions, cancer, kidney disease), and aplastic anaemia (bone marrow failure). Aplastic anaemia has a notably higher incidence in East Asian populations, including Korea, than in Western populations.
Symptoms depend on severity and rate of onset: fatigue, pallor (pale conjunctivae, nail beds, and palmar creases), breathlessness on exertion, palpitations, headache, and reduced concentration. Diagnosis requires a full blood count (FBC) with indices (MCV — mean cell volume), ferritin (iron stores), B12, folate, and further tests as indicated. Treatment is directed at the cause.
Key Points
- Most common cause: iron deficiency
- Ferritin is the best indicator of iron stores
- B12 deficiency causes large (macrocytic) RBCs
- Aplastic anaemia has a higher incidence in East Asian populations
- Treatment: address the underlying cause
Causes & Risk Factors
- Iron deficiency
- Vitamin B12 or folate deficiency
- Haemolysis (sickle cell, thalassaemia)
- Bone marrow failure
- Chronic kidney or inflammatory disease
When to See a Doctor
- Persistent fatigue with pallor
- Haemoglobin below normal on blood test
- Suspected blood loss (dark stools, heavy periods)
For emergencies in Korea, call 119
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This article is published by DoctorsInKorea.com for educational and informational purposes only. It does not replace a professional clinical evaluation by a licensed healthcare provider. For accurate medical diagnosis and personalised treatment paths, please book an appointment with a licensed KMA physician. For immediate life-threatening medical emergencies in Korea, please call 119.
Sources & References
Last reviewed: March 1, 2025