What Are the Types of Sickle Cell Disease?
1. Sickle Cell Anemia (HbSS)
Commonly known as sickle cell anemia, hemoglobin SS disease (HbSS) is a severe form and the most common type of SCD, accounting for over 70 percent of all SCD cases worldwide. The patients inherit two genes, one from each parent, coding for abnormal hemoglobin “S.” This results in rigid, sickle-shaped red blood cells. When people talk about SCD, this is the form they are typically referring to. HbSS is the type of SCD discussed throughout the rest of the guide.2. Combined Sickle Cell Hemoglobin C (HbSC)
The second most common SCD, HbSC, is a milder form, where individuals inherit a hemoglobin S gene from one parent and a gene for a different abnormal hemoglobin called “C” from the other parent. Since hemoglobin C doesn’t clump together like hemoglobin S, there’s not much “sickling” of the red blood cells in this case.3. HbS Beta-Thalassemia
HbS beta-thalassemia is a form of SCD where individuals inherit a hemoglobin S gene from one parent and a gene for beta-thalassemia from the other. Beta-thalassemia has two subtypes:- “Zero” (HbS beta-zero): HbS beta-zero-thalassemia typically results in severe SCD and is very similar to HbSS.
- “Plus” (HbS beta+): HbS beta+-thalassemia tends to have milder symptoms.
- Hemoglobin SD (HbSD).
- Hemoglobin SE (HbSE).
- Hemoglobin SO (HbSO).
What Are the Symptoms and Early Signs of Sickle Cell Disease?
Early Signs and Symptoms
The early signs and symptoms include the following:- Jaundice: Jaundice is a common sign of SCD. Sickle-shaped cells are prone to hemolysis (rupture), where sickle cells live only about 10 to 20 days instead of the usual 120. The spleen, responsible for filtering blood and preventing infections, may trap sickle cells in its filter due to their shape and stiffness, and, as a result, sickle cells suffer premature death. This faster breakdown of sickle cells can overwhelm the liver’s filtering capacity, causing the accumulation of bilirubin, a reddish-yellow pigment generated from the breakdown of red blood cells. This results in a yellowish discoloration of the skin or the whites of the eyes.
- Extreme fatigue: This is the result of anemia caused by SCD.
- Dactylitis (Hand-foot syndrome): This is often one of the first noticeable symptoms of SCD and is characterized by significant pain and swelling in the hands and/or feet. This is due to the blockage of small blood vessels by the deformed rigid blood cells, depriving the bone marrow in the hands and feet of adequate blood flow.
Splenic Sequestration (Pooling) Crisis
Due to hemolysis, the spleen enlarges (splenomegaly) as it captures rigid sickle cells. Crises occur when sickle cells accumulate in the spleen, leading to a sudden drop in hemoglobin, a protein responsible for transporting oxygen in the blood. This condition can be life-threatening without prompt treatment. The spleen can also become painful and enlarged due to increased blood volume. The signs of splenic sequestration include the following:- Pale appearance.
- Feelings of weakness or extreme fatigue.
- Enlarged spleen.
- Abdominal pain.
Aplastic Crisis
An aplastic crisis occurs when the production of red blood cells in the bone marrow stops, especially during a severe infection caused by the human parvovirus. This can lead to acute erythroblastopenia, a sudden life-threatening decrease in red blood cells. Aplastic anemia is marked by the near absence of even immature red blood cells (reticulocytes) in the bloodstream.Pain Crisis (Vaso-Occlusive Crisis)
A pain crisis, or sickle crisis, is the most common type of acute SCD crisis. It occurs when blood flow is blocked because sickle-shaped cells clump together, causing blockages in small blood vessels. This obstruction disrupts normal blood flow, leading to a range of complications. Pain can occur anywhere but is most common in the arm, leg, chest, and spine bones. Infants and toddlers may experience dactylitis as a result. Any disruption in blood flow can lead to pain, swelling, dysfunction, and potential tissue damage or death due to insufficient blood and oxygen supply. The pain can be intense and endure for days or even weeks. In addition, pain crises’ frequency can vary, with some people experiencing one every week while others may have fewer than one per year.- Anemia: Anemia occurs due to the short lifespan or destruction of sickle cells, leading to a decreased number of red blood cells. Severe anemia can cause dizziness, extreme fatigue, shortness of breath, and irregular heartbeat.
- Acute chest syndrome: Acute chest syndrome is a frequent cause of death in SCD, resulting from blockages in lung blood vessels. It is most common in childhood, with mortality rates of up to 10 percent. Repeated episodes increase the risk of chronic pulmonary hypertension. This life-threatening condition mimics pneumonia, occurring suddenly during stress from infection, fever, or dehydration. Sickle cells clump together, obstructing oxygen flow in the lungs’ tiny vessels, leading to symptoms such as fever, pain, a severe cough, and respiratory failure.
- Stroke: Sickle-shaped cells can block major blood vessels supplying oxygen to the brain, causing severe brain damage. Individuals with sickle cell anemia who experience one stroke are at a higher risk of subsequent strokes. In this case, patients need ongoing preventive treatment through regular and continuous blood transfusions for the rest of their lives. Warning signs of a stroke include sudden weakness, numbness on one side, confusion, or difficulties with vision, speech, or movement.
- Hepatic sequestration: Hepatic sequestration can occur in both children and adults, leading to pain in the upper right part of the abdomen. The liver might swell quickly, which could be associated with issues such as bile flow blockage in the liver and kidney failure.
- Infections: By toddlerhood, most children with SCD have a permanently damaged spleen, increasing the risk of life-threatening bacterial infections. It’s crucial to monitor for fevers above 101 F as potential signs of infection and seek prompt medical attention.
- Priapism: Priapism is a painful and unwanted erection that lasts for four hours or longer, resulting from obstruction of the blood vessels in the penis due to sickling. When this condition occurs, a patient should see a hematologist and urologist immediately. Without prompt treatment, it can lead to impotence. Young children (boys) can also experience this condition.
- Stunted growth and delayed puberty: Children with SCD often grow more slowly, reaching puberty later than their peers due to having fewer red blood cells. Adults with the condition are typically shorter and thinner than the general population.
- Gallstones: SCD is linked to a higher risk of gallstones resulting from increased red blood cell breakdown and a subsequent rise in serum bilirubin.
- Leg ulcers: Adolescents and adults may experience painful ulcers on the lower legs. This is due to poor blood circulation.
- Vision issues: People with SCD may experience eyesight issues, including spots in vision, blurry or uneven eyesight, reduced night vision, and occasional sudden vision loss.
- Kidney/urinary problems: Individuals with SCD may experience kidney or urinary issues, such as blood in the urine and nighttime bedwetting.
What Causes Sickle Cell Disease?

It’s important to note that the chances remain the same with each child, regardless of the outcome with previous children. If the first child has SCD, there is still a 25 percent chance the second child will also have it. Both boys and girls can inherit the sickle cell trait or SCD.
Most individuals with only the sickle cell trait lead normal lives without symptoms. While some may experience complications, further research is needed to understand when and how the sickle cell trait might impact health. Over 2 million people in the United States have the sickle cell trait.

Who Is at Risk of Sickle Cell Disease?
- People from certain ethnic groups: SCD affects approximately 1 in 365 black or African American births. About 1 in 13 black or African American babies are born with the sickle cell trait. Around 1 in 16,300 Hispanic births are affected by SCD. People of Middle Eastern, Mediterranean, Southern European, and South Asian ancestry are also at risk.
- People with a family history of SCD: You may be a sickle cell trait carrier if you have a family member or relative with SCD.
- People living in malaria-infected regions: Although people with the severe form of SCD tend to have shorter life expectancy than average, carriers of the sickle cell trait possess a protective advantage against malaria. Research indicates that the sickle cell trait offers around 60 percent protection against malaria mortality. This protection is most significant between 2 and 16 months of life, occurring before the development of clinical immunity in regions with high malaria transmission. Consequently, the prevalence of the sickle cell trait is increased in malaria-endemic areas or areas that used to be infected by malaria. These include sub-Saharan Africa and parts of Oceania.
How Is Sickle Cell Disease Diagnosed?
Prenatal Tests
Prenatal diagnostic tests include the following:- Chorionic villus sampling (CVS): Also called chorionic villus biopsy, CVS is a prenatal test for chromosomal and genetic abnormalities. It involves taking placental tissue, specifically tiny, finger-like projections called chorionic villi, which share the same genetic material as the fetus. This test is usually performed between the 10th and 12th weeks of pregnancy.
- Amniocentesis: Amniocentesis is a procedure to extract a small sample of amniotic fluid surrounding the fetus. The clear and pale yellow amniotic fluid contains cells with genetic information shed by the fetus. This information is used to diagnose genetic disorders.
Newborn Screening Tests
For children born in the United States, SCD or the sickle cell trait is most commonly identified shortly after birth as part of routine newborn screening tests conducted at the hospital. These include the following:- Newborn screening blood test: This test involves pricking the baby’s heel to obtain a blood sample and screens for conditions aside from SCD. A positive newborn screening test suggests a potential condition, but further testing is needed to confirm the baby’s sickle cell status (i.e., SCD or sickle cell trait).
- Hemoglobin electrophoresis: Also known as the sickle cell screen test, hemoglobin electrophoresis measures various types of hemoglobin in the blood, including abnormal ones. A health provider uses a small needle to obtain a blood sample from the baby’s heel. Then, the lab applies an electric current to separate the different hemoglobin types for individual measurement.
Tests in Adulthood
Tests for adults to establish sickle cell status usually include hemoglobin electrophoresis and the following:- Complete blood count (CBC): This blood test measures the levels of white blood cells, red blood cells, and platelets in the blood and evaluates the patient’s oxygen-carrying capacity. A Mean Corpuscular Volume (MCV) is included in the CBC, as abnormalities can signal the presence of other abnormal hemoglobins, such as the beta-thalassemia trait.
- High-performance liquid chromatography (HPLC): This test is usually performed if a screening test determines the possibility of abnormal hemoglobin. It determines the type of hemoglobin present in a blood sample. A health care professional typically uses a needle to draw the blood sample, usually from the arm. A genetic test may be conducted to validate HPLC results.
- DNA test: Genetic testing clarifies the type of SCD or confirms a diagnosis if blood test results are ambiguous. It also indicates whether an individual possesses one or two copies of the sickle hemoglobin gene. Some researchers advocate that molecular genetic testing should be incorporated into universal newborn screening for SCD.
What Are the Complications of Sickle Cell Disease?
- Avascular necrosis (bone tissue death): Sickle cells can obstruct blood flow to bones, leading to avascular necrosis, also known as osteonecrosis. Inadequate blood supply can cause joint narrowing and bone collapse, commonly seen in the hip joint but also other areas. This condition may start without symptoms, but as it advances, it can cause varying degrees of joint pain in the affected area.
- Deep vein thrombosis (DVT): Deep vein thrombosis is characterized by the formation of blood clots in the deep veins of the body, especially in the legs, thighs, pelvis, and arms. These clots can obstruct blood flow, causing pain, swelling, and red-blue discoloration of the skin. If a clot breaks loose and travels through the bloodstream, it can lead to a potentially life-threatening condition known as a pulmonary embolism (PE), where it lodges in the lungs. Symptoms of PE include difficulty breathing, irregular heartbeat, chest pain, coughing up blood, very low blood pressure, and lightheadedness. Both DVT and PE can lead to severe illness, disability, and death.
- Multiorgan failure: This potentially fatal condition is caused by insufficient blood flow reaching multiple organs.
- Sleep-related disorders: SCD can result in lung problems leading to breathing and sleep disorders, including sleep apnea in the absence of obesity. Sleep disorders have been noted in SCD both in the presence and absence of large tonsils. Lower airway disease may also be a contributor.
- Pulmonary hypertension: Pulmonary hypertension, high blood pressure in the lungs, has a 6 percent to 10 percent incidence rate and 2 percent to 5 percent mortality rate. It can originate from several causes, including chronic blood clots forming in the lungs, lung tissue scarring, or heart damage that impedes easy blood flow from the lungs to the heart. This also manifests as reduced exercise capacity.
- Lung fibrosis: Individuals experiencing frequent episodes of acute chest syndrome may develop scattered areas of lung fibrosis, typically found in the lower parts of the lungs. Lung fibrosis is when lung scarring obstructs oxygen transfer from air sacs to the bloodstream.
- Chronic kidney failure: Kidney problems are prevalent in SCD, with 30 percent of adults experiencing chronic kidney failure. This is because central kidney tissue is normally a low oxygen environment with higher acidity and has a high concentration of solutes. All of this dehydrates the abnormal sickle cells, leading to blockage of the kidneys’ blood vessels.
- Proliferative retinopathy: Proliferative retinopathy is a common eye issue in SCD, occurring when the small blood vessels on the edge of the retina get blocked.
- Neurological complications: SCD is associated with a higher incidence of neurological complications, including seizures and epilepsy. Seizures are 10 times more likely in child SCD patients than in the general population.
- Infections: Over time, as the spleen loses functionality, individuals with SCD experience different types of infections, including bone (osteomyelitis), gallbladder (cholecystitis), lung (pneumonia), and urinary tract infections.
- Reduced life expectancy: In the United States, individuals with SCD covered by public insurance have an average life expectancy of 52.6 years. At birth, males have a life expectancy of 49.3 years, and females have one of 55 years.
What Are the Treatments for Sickle Cell Disease?
1. Blood or Bone Marrow Transplantation
Blood and bone marrow transplants, also called hematopoietic stem cell transplants, can be performed for some SCD patients. Hematopoietic stem cells are versatile, primitive cells that can differentiate into various blood cell types. They can be found in bone marrow.2. Blood Transfusion
For SCD, blood transfusion is a standard and safe procedure. It may include several types, including simple blood transfusion or exchange transfusion. In a simple blood transfusion, the patient receives donor blood, which helps increase the overall hemoglobin levels. In an exchange transfusion, some of the patient’s blood is removed and replaced with donor blood, aiming to reduce the concentration of sickle red blood cells and improve overall blood composition. Blood transfusions can help prevent and treat certain SCD complications, including stroke, severe anemia, and acute chest syndrome. However, they are unhelpful in some cases, such as an uncomplicated pain crisis.3. Medications
The following medications are often used to treat SCD:- Voxelotor: Voxelotor is an oral medication for individuals aged 4 and older that helps prevent the formation and fusing of sickle-shaped red blood cells.
- Crizanlizumab-tmca: Administered through an IV, crizanlizumab-tmca is approved for individuals aged 16 and older to prevent blood cells from catching on vessel walls and causing blockages, inflammation, and pain crises.
- Hydroxyurea and L-glutamine: Hydroxyurea is generally recommended for daily use in individuals with hemoglobin SS or S beta-thalassemia to reduce complications, such as frequent painful crises, acute chest syndrome, and severe anemia. It is not recommended for use during pregnancy. Patients who don’t respond to hydroxyurea can take L-glutamine, an oral medication that can reduce the frequency of pain crises, the number of hospital stays, and the incidence of acute chest syndrome in individuals age 5 and older.
- Pain medications: Over-the-counter pain relievers such as acetaminophen and ibuprofen can be used for mild to moderate pain and fever. Severe or intense pain may require hospital treatment.
- Antibiotics: Penicillin, given twice daily, reduces children’s risk of severe bloodstream infections. While some health care providers may discontinue this antibiotic after age 5, others may continue prescribing it for individuals with hemoglobin SS or those who have undergone spleen removal or had a previous pneumococcal infection. Those with impaired or absent spleen function should consider staying current on pneumococcal vaccines.
- Iron chelators: These medications are for SCD patients with too much iron.
4. Potential Genetic Therapies
Genetic therapies altering a person’s hematopoietic stem cells could potentially cure SCD for those without a suitable bone marrow donor. Modified stem cells injected into the bloodstream travel to the bone marrow, generating healthy red blood cells, thus preventing sickling. In November, the United Kingdom became the first country to approve one gene treatment to cure SCD. The FDA approved CRISPR gene-editing therapies in the United States on Dec. 8.How Does Mindset Affect Sickle Cell Disease?
- Support emotional well-being: A positive mindset can contribute to emotional well-being, helping individuals cope better with the challenges associated with SCD. Cultivating a positive outlook can also assist in managing stress, which is crucial for individuals with SCD, as stress can exacerbate symptoms and trigger crises.
- Encourage better physical health: Positivity can benefit physical health for many conditions. Specifically, negative emotions have been associated with increased opioid use in individuals with SCD, which further damages patients’ physical health. According to one study, patients reported frequently having intense emotions prior to pain crises. Since a positive mindset can reduce negative emotions, it contributes to enhanced physical health for people with SCD.
- Foster social support: A positive outlook can attract and foster social support, reducing the SCD burden for both patients and their caregivers.
What Are the Natural Approaches to Sickle Cell Disease?
1. Nutrition and Supplements
- Omega-3 fatty acids: Omega-3 fatty acids, found in fatty fish such as salmon, may serve as a beneficial, safe, and cost-effective treatment for sickle cell anemia. In one study involving 140 patients, omega-3 treatment reduced the frequency of pain crises, severe anemia, blood transfusions, and related school absenteeism in individuals with sickle cell anemia.
- Zinc: Individuals with SCD often suffer from zinc deficiency. Research indicates that taking zinc supplements might alleviate symptoms of the condition. It may also enhance zinc levels in plasma, red blood cells, and white blood cells, increasing growth and body weight in teenage SCD patients. One study found that, while zinc didn’t prevent infections in children with SCD, researchers found a lower incidence of stroke or death in the zinc cohort.
- Magnesium: In SCD, insufficient magnesium levels are linked to increased sickling, enhanced polymerization, and blood vessel blockage due to cell dehydration. Intravenous magnesium has been found to reduce the length of hospital stays for children experiencing SCD pain crises. In another study, taking dietary magnesium pidolate supplements for four weeks helped decrease dehydration. Taking the supplements for six months reduced the number of painful days for people with SCD.
- Vitamin D: In one study, subjects were given a six-week course of high-dose cholecalciferol (vitamin D3) supplements. During the six months after supplement intake, the subjects experienced higher levels of vitamin D in their blood and fewer days of pain per week, and they reported better quality of life in terms of physical activity. This indicates a potential positive effect of vitamin D in reducing the frequency of pain days in SCD.
- Dietary nitrates: According to one animal study, nitrite plays a role in reducing damage to red blood cells caused by calcium influx and the clumping together of circulating blood cells. The researchers suggested that nitrite could be used as a focused carrier for nitric oxide, especially in areas with low oxygen levels, such as small blood vessels and veins. This focused activation of nitrite may offer benefits in SCD, where oxygen availability is a concern. Thus, nitrite has potential healing effects in SCD. Dietary nitrate (NO3) is primarily found in green, leafy vegetables. Nitrates in the diet can transform into nitrites (NO2) with the help of bacteria in the mouth or stomach. Subsequently, nitrites are converted into nitric oxide (NO) through a nonenzymatic process. Nitric oxide serves as a vital signaling molecule in the body and acts as a vasodilator, relaxing blood vessels to enhance blood flow and improve circulation.
2. Medicinal Herbs and Plant-Based Medicines
People in West Africa, where SCD is common, have traditionally used medicinal herbs for treatment, a practice still observed in rural communities today. Niprisan is a pharmaceutical comprised of herbal medicine for sickle cell anemia and developed by an institute under Nigeria’s Federal Ministry of Health. It is derived from pepper seeds, clove flower buds, caprium stems, sorghum leaves, and trona. According to a Nigerian review, the medicine appears to be effective in reducing severe SCD pain crises without adverse events. However, further research is needed to confirm its efficacy. The FDA hasn’t approved it. The following are some of the components of Niprisan:- Clove (Eugenia caryophyllata): A substance called beta-caryophyllene, found in clove, can bind to cannabinoid receptors, the activation of which plays a role in pain regulation. Beta-caryophyllene showed similar effects to cannabinoids in mice. This suggests it may help alleviate pain in humans and benefit individuals with SCD.
- Sorghum (Sorghum bicolor): Sorghum leaf sheath, which includes dried leaves and stems, and its extract have been used in different forms such as infusions, colorants, and dyes to help treat anemia and SCD. Additionally, it has been used against malaria, parasites, and insects. The extract from sorghum leaves prevented the clumping together (polymerization) of hemoglobin S, the molecule responsible for sickle cell formation. Therefore, this extract could potentially decrease the number of sickle cells in the blood. However, more trials are needed to confirm the plant’s effectiveness for SCD.
- West African black pepper (Piper guineense): West African black pepper contains compounds such as Shikimic acid and cannabinoids, which can help alleviate painful SCD symptoms.
3. Physical Therapies
The following therapies might help reduce SCD symptoms:- Yoga: Yoga has been found to reduce pain in both adults and children with SCD. It also lowers inflammatory markers and increases beta-endorphin, which is linked to pain relief. Researchers suggest that individuals can learn and use yoga at home to manage pain.
- Massage therapy: Research shows that massage therapy can significantly reduce pain, stress, and anxiety for children and young adults with SCD. Even massage therapy performed by parents has similar effects.
- Acupuncture: As research on acupuncture’s effects on acute pain management for SCD is limited, it remains a promising yet understudied physical therapy for SCD pain crises in both children and adults with SCD. Although only a handful of small studies have been conducted on acupuncture as a therapy for SCD, the results have all been positive.
4. Self-Care
To minimize and reduce the frequency of pain crises and manage SCD, individuals can practice the following:- Stay hydrated.
- Avoid extreme temperatures, which can trigger a crisis.
- Steer clear of high altitudes and low oxygen environments.
- Prevent infections with frequent handwashing and practicing safe food preparation.
- Take folic acid supplements, as approved by their doctor.
- Perform mild-to-moderate exercise, as intense physical activity boosts blood flow and may result in severe complications.
- Avoid traveling in an unpressurized aircraft cabin, which may result in a lack of oxygen in the body.
- During air travel, stay well-hydrated by drinking plenty of water and fluids, especially at altitudes above 5,000 feet, to prevent potential issues.
- Consume fruits, vegetables, and whole grains while limiting saturated fats, sodium, and added sugars for better heart health.
- Avoid smoking and alcohol since they can decrease oxygen levels or the body’s oxygen-carrying capacity.
How Can I Prevent Sickle Cell Disease?
Though you cannot prevent the disease itself, it is essential with SCD to stay up to date on routine checkups to avoid complications. For instance, regular eye exams to check for retinal damage are crucial for preventing vision loss associated with SCD. Laser treatment is also commonly used to prevent SCD-induced vision loss if the retina experiences damage due to excessive blood vessel growth.