Symptoms to recognise
Many people with mild anaemia have no symptoms. As haemoglobin falls further, the body compensates by increasing heart rate and redirecting blood to vital organs — which produces a characteristic constellation of symptoms.
- Persistent fatigue disproportionate to activity level
- Breathlessness with light exertion
- Pallor — pale skin, pale inner eyelids or pale nail beds
- Rapid or irregular heartbeat (palpitations)
- Headaches and difficulty concentrating
- Cold hands and feet
- Dizziness or lightheadedness, especially on standing
- Brittle nails and hair loss (in iron deficiency specifically)
- Cravings for ice, clay or non-food substances (pica) — a striking symptom of iron deficiency
Types and causes
What the blood test shows
A full blood count (FBC or CBC) is the starting point. It gives haemoglobin, red cell count, haematocrit and — critically — the MCV (mean corpuscular volume), which tells the doctor whether red cells are small (microcytic), normal or large (macrocytic). This narrows the cause significantly before other tests are done.
Iron studies (ferritin, serum iron, transferrin saturation) confirm or exclude iron deficiency. B12 and folate levels identify nutritional anaemias. A reticulocyte count reveals whether the bone marrow is responding appropriately or failing.
Treatment depends on the cause
Iron deficiency is treated with oral iron supplements — most commonly ferrous sulphate. Oral iron works well but takes 3–6 months to replenish stores fully; improvement in haemoglobin is usually visible within 4–8 weeks. Intravenous iron is used when oral iron is not tolerated, not absorbed, or the deficiency is severe.
B12 deficiency is treated with intramuscular injections or high-dose oral B12, depending on the cause. If pernicious anaemia is diagnosed — where the gut cannot absorb B12 — injections are required lifelong.
When to seek urgent care
Seek same-day assessment if anaemia is causing chest pain, severe breathlessness at rest, fainting, or if you notice blood in your stool or urine — these suggest either a cardiac complication or an ongoing source of blood loss that needs immediate investigation.