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Sickle Cell Anaemia Symptoms That Should Not Be Ignored
Certain symptoms can indicate an acute sickle cell complication involving the lungs, brain, spleen, blood or other tissues. Prompt medical assessment is particularly important when symptoms appear suddenly or worsen rapidly.
The table below highlights important symptoms and what they may indicate:
| Symptom | What It May Indicate |
| Severe or persistent pain | A vaso-occlusive pain crisis caused by blocked blood flow |
| Fever | A potentially serious infection or another sickle cell complication |
| Chest pain, cough or breathing difficulty | Acute chest syndrome affecting the lungs |
| Sudden weakness, numbness or speech difficulty | Possible stroke caused by disrupted blood flow to the brain |
| Extreme tiredness, dizziness or fainting | Severe anaemia caused by a sudden reduction in circulating red blood cells |
| Sudden abdominal swelling or pain | Splenic sequestration, where blood becomes trapped in the spleen |
| Sudden changes in vision | Reduced blood flow or damage affecting the retina |
| A painful erection lasting several hours | Priapism caused by impaired blood flow in the penis |
Why Do Sickle Cell Anaemia Symptoms Occur?
Sickle cell anaemia symptoms occur because abnormal haemoglobin S can make red blood cells rigid, sticky and sickle-shaped. These fragile cells break down earlier than normal red blood cells, causing haemolytic anaemia. Reduced red blood cell count and oxygen delivery can lead to tiredness, weakness, dizziness, and breathlessness.
The breakdown of red blood cells also increases bilirubin, causing jaundice. Sickled cells can block small blood vessels and reduce oxygen supply to tissues, producing severe pain and sometimes damaging the lungs, brain, spleen, kidneys, eyes or bones. Repeated vaso-occlusion explains many of the acute and long-term complications of sickle cell anaemia.
Sickle Cell Anaemia Symptoms That Require Immediate Medical Attention
Sickle cell anaemia can cause complications that progress quickly and require emergency treatment.
It is recommended to seek urgent medical attention if you notice the following:
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Severe pain that is unusual, persistent or not improving
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Fever, particularly 38.0°C or higher, or the threshold advised by the treating sickle cell team
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Chest pain, cough, fever or difficulty breathing
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Sudden weakness or numbness on one side of the body
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Sudden confusion or difficulty speaking, walking or seeing
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Severe dizziness, fainting, extreme tiredness or an irregular heartbeat
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Sudden abdominal swelling with weakness or pallor
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A painful erection lasting four hours or longer
Fever can sometimes be the only obvious sign of serious infection, particularly in children with sickle cell disease.
Symptoms of Sickle Cell Anaemia Based on Type
Sickle cell disease includes several inherited haemoglobin disorders. Although many symptoms overlap, their severity can differ depending on the specific haemoglobin variant.
The table below summarises the major types of sickle cell disease and their typical symptom patterns:
| Type of Sickle Cell Disease | Common Symptoms |
| Haemoglobin SC (HbSC) | Can cause pain crises, tiredness, jaundice and other sickle cell complications similar to sickle cell anaemia, but severe anaemia is generally less common and symptoms may be milder overall. |
| Haemoglobin Sβ⁰-Thalassaemia (HbSβ⁰) | Usually causes severe symptoms similar to HbSS, including recurrent pain episodes, significant anaemia, jaundice and complications caused by blocked blood flow. |
| Haemoglobin Sβ⁺-Thalassaemia (HbSβ⁺) | Usually causes milder symptoms than HbSS or HbSβ⁰, although pain crises, anaemia and other complications can still occur. |
| Rare Types such as HbSD, HbSE and HbSO | Symptoms vary depending on the haemoglobin variant and may range from mild to moderate disease, including anaemia, pain episodes and other sickle cell-related complications. |
Symptoms of Sickle Cell Anaemia-Specific Conditions
Sickle cell anaemia can cause several recognised acute complications with characteristic symptom patterns.
The table below summarises important sickle cell-related presentations:
| Condition | Common Symptoms |
| Vaso-occlusive pain crisis | Sudden or severe pain that may affect the back, chest, abdomen, arms, legs or joints |
| Acute chest syndrome | Chest pain, cough, fever and difficulty breathing |
| Splenic sequestration crisis | Sudden abdominal swelling, pallor, weakness, rapid heartbeat, breathlessness or fainting |
| Stroke | Sudden weakness or numbness, confusion, difficulty speaking, seeing or walking |
| Priapism | Persistent and often painful erection; episodes lasting four hours or longer are emergencies |
These complications need prompt assessment because acute chest syndrome, stroke and severe splenic sequestration can become life-threatening.
Sickle Cell Anaemia Symptoms in Men
Men experience the same general symptoms of sickle cell anaemia, including pain crises, anaemia, jaundice and infections. However, sickle cell disease can also cause priapism, a male-specific complication.
Symptoms of sickle cell anaemia in men may include:
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Persistent or painful erection without sexual stimulation
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Recurrent shorter episodes of painful erection
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An erection lasting four hours or longer
Priapism lasting four hours or more requires emergency treatment because prolonged interruption of normal blood flow can damage penile tissue and contribute to erectile dysfunction.
Sickle Cell Anaemia Symptoms in Women
Women experience the same main sickle cell anaemia symptoms as men. However, hormonal and reproductive changes may influence symptoms in some women.
Women may experience the following sickle cell anaemia symptoms:
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Recurrent pain crises
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Increased pain crises around menstrual periods
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Worsening tiredness or anaemia when menstrual bleeding is heavy
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Frequent pain crises or severe anaemia during pregnancy
Pregnancy can increase the risk of sickle cell complications, including acute chest syndrome, serious infection and severe anaemia, so new or worsening symptoms require medical assessment.
Sickle Cell Anaemia Symptoms in Children
Sickle cell anaemia symptoms usually begin after the first few months of life, commonly around 5–6 months of age. Painful swelling of the hands and feet, known as dactylitis, can be one of the earliest noticeable signs.
Parents or carers may notice the following sickle cell anaemia symptoms in their children:
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Painful swelling of the hands and feet
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Unusual tiredness, weakness or irritability
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Yellowing of the skin or whites of the eyes
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Recurrent fever or infections
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Episodes of unexplained pain
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Poor or delayed growth
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Delayed puberty in older children
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Sudden abdominal swelling from the enlargement of the spleen
Sudden abdominal swelling with pallor, weakness or extreme tiredness can indicate splenic sequestration and requires urgent medical assessment.
Can You Have Sickle Cell Anaemia Without Symptoms?
Sickle cell anaemia is inherited and is present from birth, but noticeable symptoms may not appear for several months. A person may also have periods when symptoms are mild or absent between pain crises.
This is different from sickle cell trait. People with sickle cell trait generally do not experience the symptoms of sickle cell disease because they carry one sickle haemoglobin gene rather than having sickle cell anaemia. Newborn screening can identify sickle cell disease before symptoms begin.
When Can Sickle Cell Anaemia Symptoms Become Life-Threatening?
Sickle cell anaemia can become life-threatening when blocked blood flow, severe anaemia or infection affects vital organs such as the lungs or brain. Certain symptoms, therefore, require immediate assessment.
The table below highlights serious symptoms and why they are dangerous:
| Symptom | Why It Is Serious |
| Chest pain, cough, fever and difficulty breathing | May indicate acute chest syndrome, which can reduce oxygen levels and cause severe lung injury |
| Sudden one-sided weakness, numbness, confusion or speech difficulty | May indicate a stroke caused by interrupted blood flow to the brain |
| Fever, particularly with marked weakness or illness | May indicate a serious infection that can progress rapidly |
| Extreme tiredness, dizziness, fainting or rapid heartbeat | May indicate severe anaemia or splenic sequestration |
| Sudden abdominal swelling with pallor or weakness | May indicate rapid trapping of blood in the spleen and a dangerous fall in circulating red blood cells |
| A painful erection lasting four hours or longer | May indicate prolonged priapism and can cause permanent tissue damage |
| Severe breathing difficulty or an irregular heartbeat | May indicate serious anaemia, acute chest syndrome or another major organ complication |
How are Sickle Cell Anaemia Symptoms Diagnosed?
Symptoms alone cannot confirm sickle cell anaemia. Blood testing identifies haemoglobin S and other haemoglobin variants, while genetic testing may be used when further confirmation is needed.
The following tests and assessments may be used to diagnose sickle cell anaemia symptoms:
| Diagnostic Test or Assessment | Purpose |
| Complete blood count (CBC) | Measures haemoglobin and other blood cells and helps identify anaemia |
| Haemoglobin analysis | Identifies haemoglobin S and other haemoglobin variants and helps determine the sickle cell genotype |
| Genetic testing | Detects relevant HBB gene variants when blood-test findings require confirmation |
| Newborn screening | Detects abnormal haemoglobin soon after birth before symptoms may become noticeable |
| Reticulocyte count | Assesses how actively the bone marrow is replacing red blood cells |
FAQs
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Q1. What is usually the first symptom of sickle cell anaemia?
Ans: Sickle cell anaemia may first cause painful swelling of the hands and feet in babies. Tiredness and jaundice can also appear early. -
Q2. What are the common symptoms of sickle cell anaemia?
Ans: Sickle cell anaemia commonly causes pain crises, tiredness, jaundice, infections and breathlessness. Symptoms vary between individuals. -
Q3. Can sickle cell anaemia be present without noticeable symptoms?
Ans: Sickle cell anaemia is present from birth, but symptoms may not appear until around 5–6 months of age and may be mild between crises.
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References
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https://www.nhlbi.nih.gov/health/sickle-cell-disease/symptoms
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https://medlineplus.gov/ency/article/000527.htm
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https://pmc.ncbi.nlm.nih.gov/articles/PMC8148117/
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