Aplastic anaemia is a rare but potentially life-threatening condition where your bone marrow stops producing enough blood cells — red cells, white cells, and platelets. It affects roughly 2 per million people annually in Europe and North America, though rates are 2-3 times higher in East Asia. Without treatment, severe aplastic anaemia has a mortality rate exceeding 70% within two years. With modern therapy — particularly bone marrow transplantation or immunosuppressive regimens — the 5-year survival rate now exceeds 75%.
If you’re reading this because you or someone you know was just diagnosed, here’s the bottom line: aplastic anaemia is serious, but it’s treatable. The key is getting to a haematologist quickly, because outcomes are dramatically better when treatment starts early and is matched to the patient’s age, disease severity, and donor availability.
What Exactly Happens in Aplastic Anaemia?
Your bone marrow is a factory that produces roughly 200 billion red blood cells, 10 billion white blood cells, and 400 billion platelets every single day. In aplastic anaemia, that factory shuts down — often because the immune system mistakenly attacks the stem cells responsible for blood production.
A bone marrow biopsy in a healthy person shows about 40-70% cellularity (meaning 40-70% of the marrow space is occupied by blood-forming cells). In severe aplastic anaemia, cellularity drops below 25%, and sometimes below 5%. The marrow is replaced by fat cells, and the blood counts plummet across all three cell lines — a finding called pancytopenia.
Symptoms: What Aplastic Anaemia Actually Feels Like
Symptoms reflect whichever cell line is most depleted. Most patients notice a combination of:
- Fatigue and breathlessness — from anaemia (low red blood cells). Haemoglobin often drops below 80 g/L at presentation.
- Recurrent or unusual infections — from neutropenia (low neutrophils). A neutrophil count below 0.5 × 10⁹/L puts you at serious infection risk.
- Easy bruising, petechiae, or prolonged bleeding — from thrombocytopenia (low platelets). Platelet counts often fall below 20 × 10⁹/L.
- Pale skin and dizziness — classic signs of significant anaemia.
The onset is usually gradual over weeks to months, though some cases — especially those triggered by viral infections — can present acutely. Many patients initially attribute their fatigue to stress or poor sleep before a routine blood test reveals the problem.
What Causes Aplastic Anaemia?
In about 60-70% of cases, the cause is idiopathic — meaning we can’t identify a specific trigger. The underlying mechanism, however, is usually autoimmune: cytotoxic T-cells attack haematopoietic stem cells for reasons we don’t fully understand.
Known causes and triggers include:
- Medications: Chloramphenicol, carbamazepine, phenytoin, sulfonamides, and certain NSAIDs
- Chemical exposure: Benzene (found in industrial solvents, petrol), pesticides, and insecticides
- Viral infections: Hepatitis (non-A, non-B, non-C), Epstein-Barr virus, CMV, parvovirus B19, and HIV
- Inherited conditions: Fanconi anaemia, dyskeratosis congenita, Shwachman-Diamond syndrome
- Radiation exposure
- Pregnancy — rare, but aplastic anaemia can develop during pregnancy and sometimes resolves after delivery
How Aplastic Anaemia Is Diagnosed
Diagnosis requires both blood work and a bone marrow biopsy. There’s no shortcut around the biopsy — it’s essential.
Diagnostic Criteria and Severity Classification
| Severity | Bone Marrow Cellularity | Blood Count Criteria (at least 2 of 3) |
|---|---|---|
| Non-severe | <25% (or 25-50% with <30% residual haematopoietic cells) | Does not meet severe criteria but has cytopenia |
| Severe (SAA) | <25% | Neutrophils <0.5 × 10⁹/L, Platelets <20 × 10⁹/L, Reticulocytes <20 × 10⁹/L |
| Very Severe (vSAA) | <25% | Same as SAA but neutrophils <0.2 × 10⁹/L |
Other tests your haematologist will order include reticulocyte count, flow cytometry (to rule out paroxysmal nocturnal haemoglobinuria, which coexists in up to 50% of aplastic anaemia patients), cytogenetics, and chromosomal breakage studies if an inherited form is suspected.
Treatment Options and Survival Rates
Treatment depends on severity, patient age, and whether a matched donor is available. Here’s how the two main treatment pathways compare:
| Treatment | Best Candidates | 5-Year Survival | Key Considerations |
|---|---|---|---|
| Matched sibling bone marrow transplant (BMT) | Age <40 with HLA-matched sibling | 80-90% | Curative; risk of graft-versus-host disease |
| Matched unrelated donor BMT | Age <50, failed IST, or no sibling donor | 70-80% | Improving outcomes with better HLA matching |
| Immunosuppressive therapy (IST) | Age >40, or no suitable donor | 60-75% | Uses horse ATG + cyclosporine; ~60-70% response rate |
| Eltrombopag + IST | Severe/very severe AA | Under study; promising | Addition of eltrombopag to IST improved overall response to ~85% in NIH trials |
Immunosuppressive Therapy (IST)
The standard IST regimen combines horse antithymocyte globulin (ATG) given intravenously over 4 days with cyclosporine taken orally for at least 12-18 months. About 60-70% of patients respond, typically within 3-6 months. However, roughly 30-40% of responders eventually relapse, and there’s a 10-15% risk of evolving into myelodysplastic syndrome or acute leukaemia over 10 years.
The thrombopoietin receptor agonist eltrombopag has been a game-changer. When added to standard IST as first-line therapy, the NIH showed complete response rates jumping from about 10% to 40%.
Bone Marrow Transplantation
For young patients (under 40) with a matched sibling donor, transplant is the treatment of choice. It offers the best chance of a permanent cure. The conditioning regimen typically uses cyclophosphamide with or without ATG. Outcomes with haploidentical (half-matched family) donors are improving rapidly and expanding transplant access.
Supportive Care
Regardless of definitive treatment, most patients need:
- Red cell and platelet transfusions (using irradiated, CMV-negative, leucodepleted products)
- Prophylactic antifungals and antibiotics when neutrophils are critically low
- Iron chelation therapy if they become transfusion-dependent (typically after 20+ red cell transfusions)
When to See a Doctor — Urgently
See a doctor immediately if you experience:
- Unexplained fatigue that worsens over days to weeks, especially with pallor
- Spontaneous bruising, petechiae (tiny red spots on skin), or bleeding that won’t stop
- Recurrent fevers or infections without an obvious cause
- A combination of any of the above — this triad is a red flag for bone marrow failure
If a complete blood count shows pancytopenia, insist on a haematology referral. Don’t accept a “wait and recheck” approach if counts are significantly low — particularly if neutrophils are below 1.0 × 10⁹/L or platelets are below 50 × 10⁹/L.
Frequently Asked Questions
Is aplastic anaemia a type of cancer?
No. Aplastic anaemia is a bone marrow failure syndrome, not a malignancy. However, it can evolve into myelodysplastic syndrome (MDS) or acute myeloid leukaemia (AML) in roughly 10-15% of cases over a decade, particularly after immunosuppressive therapy. This is why long-term monitoring with regular blood counts is essential.
Can you live a normal life with aplastic anaemia?
Many patients do, particularly after successful bone marrow transplantation or a good response to immunosuppressive therapy. Patients who achieve complete remission — normalisation of all blood counts — can return to normal activities, work, and exercise. Those with partial responses may need to manage ongoing mild cytopenias but can still live full lives with appropriate monitoring.
How quickly does aplastic anaemia progress?
It varies widely. Some patients present with a gradual decline over months, while others — especially those with post-hepatitis aplastic anaemia — can deteriorate within weeks. Severe aplastic anaemia left untreated carries a median survival of about 3-6 months due to infection and bleeding risk.
Is aplastic anaemia hereditary?
Most cases (acquired aplastic anaemia) are not inherited. However, inherited bone marrow failure syndromes like Fanconi anaemia and dyskeratosis congenita account for roughly 5-10% of cases and are more common in children and young adults. Genetic testing is recommended for patients diagnosed before age 40, as inherited forms require different treatment approaches — particularly avoiding radiation-based transplant conditioning regimens.
What’s the difference between aplastic anaemia and iron-deficiency anaemia?
They’re fundamentally different conditions. Iron-deficiency anaemia affects only red blood cells and is caused by insufficient iron. Aplastic anaemia affects all three blood cell lines (red cells, white cells, and platelets) and is caused by bone marrow failure. Iron supplements won’t help aplastic anaemia. If your blood test shows low white cells and platelets alongside anaemia, iron deficiency is not the explanation.
