Haemolytic Anaemia: Causes, Symptoms, Diagnosis, Treatment & More

Introduction

Feeling unusually tired, weak, pale, or short of breath even after resting can be worrying, especially when there is no clear reason. Sometimes, these symptoms may be linked to anaemia, a condition in which the blood cannot carry enough oxygen around the body¹. Around 1.9 billion people worldwide are affected by anaemia². This article explains haemolytic anaemia in simple terms, including its causes, symptoms, diagnosis, treatment, prevention, and when to seek medical help. 

What is Haemolytic Anaemia?

Anaemia means the body does not have enough healthy red blood cells (RBCs) to carry oxygen well. Haemolytic anaemia is a type of anaemia that happens when RBCs are destroyed faster than the bone marrow can make new ones. RBCs carry oxygen from the lungs to the rest of the body³. When too many RBCs break down too early, the body may not get enough oxygen. This can cause symptoms such as tiredness, weakness, dizziness, or shortness of breath⁴. 

Haemolytic anaemia can start suddenly or develop slowly over time. Some people have mild symptoms, while others may need urgent care. The seriousness depends on the cause and how quickly RBCs are being destroyed⁵. 

Types of Haemolytic Anaemia

Haemolytic anaemia is usually grouped into two main types: 

1. Inherited Haemolytic Anaemia

This type is present from birth and is passed down through families. It happens because of changes in genes that affect RBCs. Examples include: 

• Sickle cell disease: RBCs become sickle-shaped instead of disc-shaped. This can make them break apart faster and sometimes block blood flow^5,7. 
• Thalassaemia: The body makes less haemoglobin than it needs. Haemoglobin is the protein in RBCs that carries oxygen. This can cause RBCs to be destroyed faster^5,8. 
• Hereditary spherocytosis: RBCs become round instead of disc-shaped. This makes them less flexible and more likely to be removed by the spleen^6,9. 
• Glucose-6-phosphate dehydrogenase (G6PD) deficiency: In this inherited condition, RBCs do not have enough of an enzyme called G6PD, which helps protect them from damage. Certain medicines, infections, or foods such as fava beans can trigger RBCs to break down quickly in some people¹⁰. 

2. Acquired Haemolytic Anaemia

Develops after birth. People are not born with it; instead, healthy RBCs are destroyed because of another medical condition or an external trigger. 

• Autoimmune haemolytic anaemia: The immune system mistakenly attacks and destroys the body’s own RBCs, causing anaemia¹¹. 
• Microangiopathic haemolytic anaemia: In this condition, RBCs are damaged as they pass through very small blood vessels. This may happen in serious conditions such as thrombotic thrombocytopenic purpura, which can cause small blood clots, or haemolytic uremic syndrome, which can affect the kidneys and blood vessels¹². 
• Paroxysmal Nocturnal Haemoglobinuria (PNH):  a complement-mediated form of acquired haemolytic anaemia. A rare, acquired condition in which RBCs lack certain protective proteins on their surface, making them vulnerable to being destroyed by part of the immune system called the complement system²¹. 
• Medicine-induced haemolytic anaemia: Certain medicines can trigger RBC destruction in some people and contribute to anaemia^1,5. 
• Infection-related haemolytic anaemia: Certain bacterial, viral, or parasitic infections can damage RBCs^1,5. 

Haemolytic Disease of the Newborn

Haemolytic disease of the newborn happens when a mother’s immune system produces antibodies against her baby’s red blood cells, usually because of a blood group mismatch between them (most often involving the Rh factor or ABO blood groups). These antibodies can cross the placenta and cause the baby’s RBCs to break down faster than normal, leading to anaemia and jaundice in the newborn²⁵. 

Doctors can often screen for this risk during pregnancy through routine blood group and antibody testing, and preventive treatment (such as Rh immunoglobulin) may be given to at-risk mothers to reduce the chance of this happening in future pregnancies. After birth, affected babies are monitored closely and may need treatment such as phototherapy or, in more severe cases, a blood transfusion. 

What Causes Haemolytic Anaemia?

The cause of haemolytic anaemia depends on whether it is inherited or develops later in life. Common causes and triggers include: 

• Inherited blood conditions⁵ 
• Immune system problems 
• Problems with haemoglobin, the oxygen-carrying protein inside RBCs 
• Certain infections 
• Exposure to certain toxins, chemicals or medicines 
• Problems with proteins that help RBCs keep their shape and strength 
• Blood transfusion from an unmatched donor 
• Formation of blood clots in small blood vessels 
• Damaged or artificial heart valves that harm RBCs¹ 
• Bone marrow conditions that make it harder for the body to replace lost RBCs⁵ 

Symptoms of Haemolytic Anaemia

Mild haemolytic anaemia may not cause noticeable symptoms. When symptoms do occur, they may include: 

• Unusual weakness or tiredness (more after exercise) 
• Trouble concentrating or thinking clearly 
• Fast or racing heartbeats 
• Unusual headaches³ 
• Dark-coloured urine¹³ 

Symptoms that indicate a more severe condition include: 

• Pale skin or yellowing of the skin or eyes (jaundice)^1,7 
• Swelling of the hands and feet with pain⁷ 
• Tongue soreness 
• Shortness of breath
• Enlarged Spleen (Splenomegaly) 
• Abdominal pain (due to an enlarged spleen) 
• Dizziness/light-headedness when standing⁵ 

How Chronic Haemolysis Affects the Body?

• High-Output Cardiac Failure²¹ 
• Pigment Gallstones 
• Acute Kidney Injury 
• Iron Overload (secondary Hemochromatosis)²² 
• Aplastic Crisis 

Red Flag Triggers to Avoid

For individuals with hereditary or acquired susceptibility, certain environmental triggers can rapidly induce a haemolytic crisis: 

• Fava Beans & certain drugs (G6PD deficiency): ingesting fava beans or medications like rasburicase, nitrofurantoin, or dapsone can cause oxidative stress and rapid haemolysis 
• Cold temperature exposure v(cold agglutinin disease): cold weather, unheated liquids, or cold shower can trigger agglutination in extremities. 
• Infection: viral illnesses (e.g.: Epstein-Barr Virus, Parvovirus B19) or bacterial infections can trigger immune reactivity or transient aplastic crisis²⁴. 

How Is Haemolytic Anaemia Diagnosed?

A doctor will ask about your symptoms, medical history, recent infections, medicines, blood transfusions, and any family history of blood disorders. They may also examine you for signs such as pale skin, yellowing of the eyes or skin, or an enlarged spleen. If haemolytic anaemia is suspected, blood and sometimes urine tests may be recommended. Common tests include: 

• Complete Blood Count: This test measures different blood cells, including RBCs, as well as haemoglobin and haematocrit. 
• Reticulocyte Count Test: This test measures young RBCs, called reticulocytes. A high count can mean the body is working harder to replace RBCs that are being destroyed¹⁴. 
• Peripheral Blood Smear: In this test, the shape and appearance of RBCs are checked under a microscope. Changes in shape can help doctors look for certain types of anaemia¹⁵. 
• Pyruvate Kinase Test: This test checks for low levels of pyruvate kinase, an enzyme that helps RBCs work properly. Low levels may point to an inherited cause of haemolytic anaemia³. 
• Bilirubin Test: This test measures bilirubin, a substance made when RBCs break down. Higher bilirubin levels may be a sign that RBCs are being destroyed too quickly. 
• Lactate Dehydrogenase (LDH) Test: This test measures LDH, an enzyme released when cells are damaged. High LDH levels in the blood can be a sign of increased RBC breakdown. 
• Serum Haptoglobin Test: This test measures Haptoglobin in blood because haptoglobin binds to free haemoglobin released during cell breakdown. Low haptoglobin levels can be a sign of increased RBC breakdown²³. 
• Direct Antiglobulin Test (or Coombs Test): This test checks whether immune system proteins are attached to RBCs. A positive result may suggest autoimmune haemolytic anaemia¹⁶. 
• Haemoglobin Electrophoresis: This test checks for unusual types or amounts of haemoglobin. It can help diagnose conditions such as sickle cell disease and thalassaemia⁷. 
• Osmotic Fragility Test: This test checks whether RBCs break too easily when placed in a special solution. Cells that burst more easily than normal may suggest certain inherited types of haemolytic anaemia, such as hereditary spherocytosis¹⁶. 

Doctors may also recommend additional tests to find the exact cause. They may suggest tests such as urine tests, genetic tests, or bone marrow tests, if needed⁵. 

Note: Not everyone with haemolytic anaemia needs all of these tests. Your doctor will recommend the tests based on your condition. 

Treatment Options for Haemolytic Anaemia

Treatment depends on the cause, how severe the anaemia is, and how quickly symptoms develop. A doctor may recommend one or more of the following: 

• Treating the underlying cause: If haemolytic anaemia is linked to an infection, medicine, or another health condition, treating that problem may help. A doctor may stop or change a medicine if it is causing the anaemia⁵. 
• Medicines: Doctors may recommend medicines such as corticosteroids as first-line therapy for autoimmune haemolytic anaemia. These medicines help reduce the immune system’s attack on RBCs¹⁷. Monoclonal Antibodies & Immunosuppressants: Therapies like Rituximab²⁶ or advanced complement inhibitors like Eculizumab (for PNH) are increasingly used when steroids alone are insufficient or to reduce long-term steroid exposure²⁰. 
• Blood transfusions: People with severe anaemia or significant symptoms may need a blood transfusion. This helps restore healthy RBCs and improves oxygen delivery to the body’s tissues^3,6,7. 
• Intravenous immunoglobulin: In some cases of autoimmune haemolytic anaemia, doctors may give IVIG as a rapid, short-term bridge therapy to temporarily block immune receptors and slow down cell destruction²⁶. 
• Vitamin supplements: Supplements such as folic acid may be recommended because the body may need extra folic acid to make new RBCs. This supports healthy RBC production, especially when blood cells are being destroyed quickly³. 
• Surgery (splenectomy): In some severe or long-term cases, doctors may recommend removing the spleen as a 2^nd line intervention effective primarily in Extravascular Haemolysis. This is usually considered only when other treatments are not enough or when a specific condition makes it helpful¹. 
• Emerging, Novel Therapies: Rilzabrutinib, an oral BTK inhibitor, received FDA Breakthrough Therapy designation in February 2026 specifically for warm autoimmune haemolytic anaemia,  a subtype that currently has no FDA-approved targeted treatment. It is not yet approved for this use; a Phase 3 trial is ongoing¹⁹. 

Prevention Tips for Haemolytic Anaemia

Not all causes of haemolytic anaemia can be prevented, especially inherited forms. However, some steps may reduce the risk of acquired haemolytic anaemia or help avoid complications. 

• Follow the doctor’s advice. 
• Avoid known triggers such as eating fava beans and certain medications if you have underlying conditions like G6PD deficiency. 
• Lower your risk of infections where possible and seek treatment promptly if an infection develops¹⁰. 
• Eat a healthy, balanced diet to support RBC production. 
• If you need a blood transfusion, healthcare professionals will check that the donated blood is compatible with your blood type¹. 
• Get regular check-ups for autoimmune diseases. 

When Should You See a Doctor?

See a doctor if you have ongoing tiredness, weakness, dizziness, headaches, trouble concentrating, or a sore tongue^1,3. Seek medical help promptly if you have shortness of breath, yellowing of the skin or eyes, dark urine, severe abdominal pain, a fast or irregular heartbeat, or painful swelling of the hands or feet^3,7. Early diagnosis and treatment can help prevent serious complications. 

Also Read: High GGT Levels: Normal Range, Causes, Symptoms, Risks & Treatment

Conclusion

Haemolytic anaemia happens when RBCs are broken down faster than the body can replace them. It can have many causes, including inherited blood conditions, infections, medicines, immune system problems, or transfusion reactions. With the right diagnosis and treatment, many people can manage the condition well. If you notice symptoms such as persistent tiredness, yellowing of the skin or eyes, dark urine, or shortness of breath, speak with a doctor for proper evaluation and care. 

Frequently Asked Questions (FAQs)

References

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