Sickle Cell Disease

: What to Know

Sickle Cell Disease (SCD) affects countless people all over the world. The CDC estimates that 100,000 people in America alone have the disease.

It was first discovered in 1910 by Dr. James Herrick, who, while teaching a course on laboratory medicine, saw that one of his students who had originated from the West Indies had a strange “crescent” shaped and “sickle” shaped blood cells interspersed with normal, healthy red blood cells. He noted that the student was also anemic and breathless, with occasional bouts of jaundice. After this discovery, many similar cases were found, particularly from individuals of African ancestry. Most of the patients complained of attacks of severe pain. This was the first time “sickle cells” were observed in the medical field.

The US National Library of Medicine officially defines SCD as “a group of disorders that affects hemoglobin, the molecule in red blood cells that delivers oxygen to cells throughout the body.” What this means is that people that have this disorder have atypical hemoglobin molecules, which are called Hemoglobin S. They distort the hemoglobin blood cells, causing the hemoglobin to form stiff rods within the red blood cells. This results in transforming the cells into the namesake “sickle” or crescent shape.

What makes this a disorder is that healthy red blood cells are typically disc-like in shape, round with a concave center. They’re similar to a doughnut but without a hole. Their form enables them to make their way through the blood vessels. Their job is to transport oxygen through the various parts of the body. But for someone with SCD, their crescent-shaped cells prevent their bodies from doing this properly.

Sickle cells are not flexible, and they’re unable to change shape as quickly as typical, healthy red blood cells. As a result, the sickle cells die early, lasting only 10 to 20 days in the body, instead of the expected 90 to 120 days from healthy red blood cells. This rapid degeneration of cells, therefore, creates a constant deficit of healthy red blood cells, and the body is continuously having trouble making up new cells to make up for the lost ones. This results in the condition known as anemia, wherein the body’s bone marrow is unable to make enough red blood cells to make up for the deficit. The body then feels tired constantly from the loss of healthy red blood cells.

Another critical challenge is that when the sickle cells do travel around the body’s blood vessels, they often get stuck onto the walls of the blood vessels, or get clumped together and get lodged, causing a blockage. The blood flow then stops, and oxygen is unable to reach the nearby tissues that need it. No healthy, oxygenated blood will flow through the body’s organs and tissues. This generates what is called “pain crises,” which are onsets of sudden, severe pain, and can occur without warning. While some incidences can be treated at home, they often cause a person to be taken to a hospital for treatment. Also, the blockages and clogs put the person at risk of several other complications:

  • Acute chest syndrome – Characterized by inflammation, infection, and blockages within the small blood vessels around the lungs. The signs include chest pain, difficulty in breathing, and fever.
  • Aplastic crisis – Characterized by severe anemia brought on by the body’s temporary inability to make enough red blood cells. Paleness, extreme exhaustion or lethargy, and a rapid heartbeat are key indications.
  • Priapism – Men who have sickle cell disease can be susceptible to priapism, which causes extremely painful, long-lasting erections. Lack of immediate treatment can cause problems later in life.
  • Stroke – Because the sickle-shaped cells adhere to the walls of the blood vessels, they can clog up the blood vessels in the brain itself, causing a stroke. The signs include headaches, seizures, weakness of the limbs, facial droop and speech problems, and finally, loss of consciousness.

Apart from these complications, the lack of healthy red blood cells also makes people with SCD more susceptible to certain bacterial infections. If a person suffering from SCD starts getting 101°F fevers, it’s important to contact medical professionals right away. This situation is incredibly crucial, particularly for young children who can be easily overwhelmed by bacterial infections.

Other complications that people with SCD are at risk include leg ulcers, joint damage, gallstones, kidney and eye damage, and growth delays.

SCD is also a lifelong condition. People who have this disorder will have it from birth through the rest of their lives. Early diagnosis is crucial to the treatment and management of SCD, as it gives doctors opportunities to curb or slow down the devastating effects that SCD can have on a body. Preventative steps may be able to dramatically increase the life expectancy of a patient, as well as decrease the risk of infections and other risky complications.

People who have SCD typically begin showing signs and symptoms of the disease right away. During their first year of life, around the age of five months, the signs will start to show. However, not all people with SCD will have similar symptoms and complications. If a child starts showing signs of SCD, it’s important to get them to a doctor right away to determine if they have the disease, or if both parents are carriers of the gene.

While the signs and symptoms may vary from person to person, the common signs and symptoms of SCD include:

  • Anemia – By far, anemia is the most prominent symptom in SCD. Since sickle cells easily break apart and die, the person with SCD is left with too few blood cells at a time, and the body has trouble keeping up. Without enough red blood cells, the body can’t get an ample supply of oxygen, resulting in fatigue.
  • Pain crises – Pain crises are another major symptom and complication of SCD. These periodic episodes of pain develop from blocked blood flow throughout your body’s blood vessels. They can occur in the chest, abdomen, the joints, and even your bones. The pain will vary in intensity as well as duration. Some sufferers of SCD will have a few pain crises a year, while others may have a dozen or more. More severe instances of pain crises require hospital stays.
  • Chronic pain – Unlike pain crises, this pain is more or less constant in some people with SCD. This can come from damaged bones and joints, ulcers, and more.
  • Swelling of the hands and feet – Sickle cells can block blood flow to the hands and feet, causing unusual swelling.
  • Infections – People with SCD are more susceptible to infections, as sickle cells damage the spleen. Doctors typically give infants and children who have been diagnosed with SCD anemia and antibiotic vaccinations to prevent life-threatening diseases as well as pneumonia.
  • Delayed growth – Since blood is what brings the rest of the body oxygen and nutrients needed for growth, children with SCD have a shortage of healthy red blood cells that enable them to develop. This can result in delayed growth among infants and children or issues with puberty among teenagers.
  • Vision problems – Sickle cells can clog veins and blood vessels that supply your eyes. This can lead to retinal damage and therefore lead to problems with one’s vision.

Adults with SCD might have a host of symptoms, which include fatigue, dizziness, headaches, jaundice (a yellow tint in the skin or the whites of the eyes), rapid heartbeat, being short of breath, unusually pale skin and mucous membranes (which are the tissues in the nose, mouth, and other areas of the body).

SCD is a genetic condition, meaning it is inherited from parents through the genes in one’s DNA. A child will develop sickle cell disease if he or she receives two sickle cells “S” genes from each parent.

SCD is common among people with a sub-Saharan African ancestry, along with people who hail from Spanish-speaking regions in South America, the Caribbean and Central America, Saudi Arabia, India, and the Mediterranean (Turkey, Greece, and Italy.) 

Because of this genetic background, SCD occurs in roughly 1 of every 365 African-American births and about 1 in every 16,300 Hispanic-American births. The condition is inherited in an autosomal recessive pattern. This means that both copies of the gene in each cell have mutations. Parents of a person who has an autosomal recessive pattern each carry a copy of the mutated gene, but they would not show symptoms of the condition itself. This is known as having a sickle cell trait; 1 in 13 African-American babies is born with a sickle cell trait. SCD is seen as one of the commonly inherited blood disorders in the United States.

There are different types of SCD:

  • HbSS refers to the type of SCD where a person inherits two sickle cell genes (S), which come from both parents. This is one of the most common variants of SCD and is called “sickle cell anemia.”

Sickle cell anemia is an inherited red blood cell disorder that causes the body to be unable to carry oxygen throughout its different parts due to a shortage of healthy red blood cells. There is no cure for this disease, though there are treatments to prevent complications.

  • HbSC is a type of SCD where a person will inherit the sickle cell gene “S” from one parent while they inherit from another parent an abnormal hemoglobin gene called “C.” Hemoglobin itself is a protein that helps red blood cells carry oxygen to various parts of the body. This type of SCD is considered “milder” than others.
  • HbS beta-thalassemia refers to the form of SCD wherein a person will inherit one sickle cell gene “S” from one parent, and a gene for beta-thalassemia from the other parent. This is another form of anemia, of which there are two types: “0” and “+.” HbS beta 0-thalassemia is seen as a severe form of SCD, while people who suffer from HbS beta +-thalassemia have the milder form.
  • HbSD, HbSE, and HbSO are all the rarer forms of SCD. People who suffer from this disorder have inherited one sickle cell gene “S” and one gene that signals an abnormal type of hemoglobin (which are the “D,” “E,” and “O” respectively.) The severity of these types of SCD will vary among individuals.

While a person may have SCD, their parents may have the Sickle Cell Trait (SCT) without showing signs of the illness itself. SCT is HbAS, where a person inherits one sickle cell gene “S” from one parent and a normal gene from the other. The people with SCT are free of the signs of the disease and typically lead normal lives. However, they are able to pass the trait down to their children.

One can calculate the likelihood that a child will inherit SCD if one or both parents have the SCT as follows:

  • Assuming both parents have SCT, there is approximately 1 in 2 or a 50% chance that their child would also have SCT themselves if they inherit one gene from either parent. These children are unlikely to develop symptoms of SCD, but being SCT themselves means that they can pass the trait on to their children as well.
  • However, as both parents have SCT, this means that there is a 1 in 4, or 25% chance that their offspring will also develop SCT. There is also a 25% chance that their child would have neither SCD or SCT.

Even with only SCT, some complications may arise. Though people with SCT don’t have the symptoms of SCD, rare complications might arise if brought about by difficulties in adapting to specific environments.

While this happens only in the most extreme and rare cases, people with SCT might find themselves at risk during:

  • Increase pressure in the atmosphere (e.g., scuba diving)
  • Low oxygen levels in the air (e.g., during mountain climbing, arduous physical training or exertion)
  • Dehydration
  • High altitudes (experienced during flying, mountain climbing, hiking, or even visiting a high-altitude city)

There are a variety of methods that modern medicine uses to diagnose and test for SCD. The primary method to do it is through a simple blood test. Most often, SCD can be flagged during a routine blood test for a newborn in the hospital. All states now screen newborns for SCD and other genetic diseases as part of standard screening programs. This enables doctors and parents to diagnose the disorder at the earliest possible time and begin treatment as early as possible.

During the blood test, the sample is analyzed to determine what type of hemoglobin is present. This can be done through hemoglobin electrophoresis or other methods. What they’re looking for in particular is hemoglobin S, the defective type. Human confirmation can also be done, wherein the blood sample is viewed under a microscope to check for the hallmark “sickle” cells. This type of test can diagnose most cases of SCT and SCD. However, should further tests be needed or if the result is unclear, genetic testing can be performed to make a diagnosis.

It’s also possible to test if a baby has SCD before birth. Both parents can have themselves tested to check if they have SCT and see the likelihood of their producing a child with the trait or the disorder. Doctors can also diagnose SCD on a baby in utero through amniocentesis, which is when a sample of amniotic tissue or fluid is taken from the placenta. 
Genetic testing is another (voluntary) method to determine markers or indicators of genetic conditions such as SCD. There are several methods available for parents and children. Molecular genetic tests or gene tests will study single genes or short lengths of DNA variations. They look into the mutations that could lead to a genetic disorder.


There is no single most effective treatment for people suffering from SCD. However, certain medications may alleviate some issues.

  • Hydroxyurea is generally considered a safe medication to treat SCD when administered by medical specialists that have long experience in caring for patients with SCD. However, pregnant women may want to consult with their doctors before taking this medication.
  • Endari (an L-glutamine oral powder) has also been approved by the Food and Drug Administration for reducing the number of sickle cell crises within adults and children aged five-years-old and up.
  • Antibiotics are recommended to prevent infections from taking hold in younger children.
  • Pain relievers are available for pain crises and chronic pain. Still, when the pain is so severe that not even standard medication can alleviate them, it’s recommended that the patient seek emergency services.
  • Childhood immunizations are also recommended for babies and young children to protect them from life-threatening diseases.

Diet & Lifestyle:

When it comes to the management of SCD, doctors recommend specific diets and lifestyle changes.

  • Eat a balanced diet, along with folic acid supplements. Folic acid is vital in the creation of healthy red blood cells and reduces the impact of anemia.
  • Stay hydrated; dehydration is a risk among individuals with SCD. Drink plenty of water every day to reduce risks of blood cells clumping together and leading to a sickle crisis.
  • Avoid excessive exercise as this may cause difficulty in breathing and accelerated heart rates, with oxygen in your body getting lowered.
  • During an acute sickle cell pain crisis, get in touch with your medical care team. Be observant of symptoms that should prompt a call to the doctor.
  • Avoid emotional and physical stress.
  • Avoid factors that can worsen your condition or lead to infection. These include tobacco, cocaine, methamphetamines, and alcohol.

Therapy and Procedures

One of the more common therapy procedures for SCD, and the only one that may cure it, is a stem-cell transplant or a bone marrow transplant. The procedure infuses healthy cells into the body to replace damaged and diseased bone marrow, where blood cells are made. There have been successful transplants of bone marrow or blood from healthy donors and have then successfully cured SCD. However, this requires a matched donor (someone with compatible bone marrow to the recipient). Transplants also run the risk of severe side effects, including life-threatening illness and death. It’s essential to consult with your doctor.

Blood transfusions are also a standard procedure for individuals with SCD as they are used to treat severe anemia. Sudden anemia resulting from infections, as well as an enlargement of the spleen, is a common cause for transfusion. Too many, however, may lead to iron overload or hemosiderosis, which damages the liver, heart, pancreas, and other internal organs. Iron chelation therapy can be implemented for patients who receive regular transfusions.

Emergency Care

Emergency care is often necessary for individuals with SCD if they exhibit the following:

  • Fever (usually at 101°F (38°C) or higher)
  • Severe pain that can’t be alleviated by over-the-counter medication
  • Chest pains
  • Severe headaches and dizziness
  • Seizures
  • Slurred speech
  • Loss of consciousness
  • Jaundiced or pale skin
  • Numbness and tingling
  • Swelling of the hands and feet
  • Abdominal swelling
  • Signs and symptoms of stroke

Digitization has played a role in the advancement of treatment and maintenance for people with SDC. It’s easier to keep track of treatments, medical information, and paperwork with the advent of EMRs or electronic medical records.

Further advancement in treatments for SCD has included annual screening, checking for stroke risks, and preventative treatments for high-risk children. More vigilant care of children with SCD from a young age has improved overall life expectancy.

There are also active studies looking for ways to prevent heart, lung, kidney problems, as well as the development of new medication against sickling and the duration of sickle cell pain crises. Gene therapy offers hope for a cure as well.

What precautions should an active person with SCD take?

Extra precautions for someone with SCD include avoiding excessive exertion, heat, humidity, and dehydration.

When should a person with SCD see a counselor?

People with SCD might be unaware of their status, and hematologists recommend that they are made aware of it as the soonest possible occasion. Primary-care providers, along with hematologists and genetic counselors, can provide care for both physical and mental wellbeing when it comes to coping with SCD.

How long is the life expectancy of a person with SCD?

The advancement of medicine has dramatically lengthened the lifespan of people with SCD. Now that all children are screened for it, life expectancy has increased to at least 40 years.

How can I get the right testing?

If you feel that you or your child has symptoms of SCD, visit a specialist immediately. 

Make sure to bring with you any personal medical records that can help verify whether or not the suspected individual might have SCD. If you would like help obtaining your medical records, PicnicHealth can do the hard work of collecting and organizing your medical records into a secure, digital Timeline. PicnicHealth also enables people to make their voice heard by contributing their records anonymously to research into new treatments for Sickle Cell Disease. Visit to learn more.

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