Sickle Cell Crisis: Treatment, Pain Relief, and Prevention Options

A sickle cell crisis can cause severe pain that begins suddenly and may require urgent medical treatment. For people living with sickle cell disease, these episodes can disrupt school, work, sleep, family life, and daily activities. Some episodes can be managed according to an established home pain plan, while others require treatment in an emergency department or hospital.

The medical term often used for an acute sickle cell pain crisis is a vaso-occlusive episode, or VOE. The term vaso-occlusive crisis, or VOC, is also widely used. These episodes occur when sickled red blood cells and other cellular and inflammatory processes contribute to impaired blood flow and tissue injury.

Treatment depends on pain severity, symptoms, previous complications, and the individual’s established care plan. Acute management can include pain medication and other supportive measures, while longer-term strategies may involve hydroxyurea, other disease-modifying treatments, transfusion programs for specific indications, or advanced therapies such as hematopoietic stem cell transplantation and gene therapy.

Sickle cell disease care has changed substantially. There is still no single treatment appropriate for every person, but the options now extend far beyond simply enduring recurrent episodes of pain.

A sickle cell crisis can cause severe pain that begins suddenly and may require urgent medical treatment. For people living with sickle cell disease, these episodes can disrupt school, work, sleep, family life, and daily activities. Some episodes can be managed according to an established home pain plan, while others require treatment in an emergency department or hospital.

The medical term often used for an acute sickle cell pain crisis is a vaso-occlusive episode, or VOE. The term vaso-occlusive crisis, or VOC, is also widely used. These episodes occur when sickled red blood cells and other cellular and inflammatory processes contribute to impaired blood flow and tissue injury.

Treatment depends on pain severity, symptoms, previous complications, and the individual’s established care plan. Acute management can include pain medication and other supportive measures, while longer-term strategies may involve hydroxyurea, other disease-modifying treatments, transfusion programs for specific indications, or advanced therapies such as hematopoietic stem cell transplantation and gene therapy.

Sickle cell disease care has changed substantially. There is still no single treatment appropriate for every person, but the options now extend far beyond simply enduring recurrent episodes of pain.

What Is a Sickle Cell Crisis?

Sickle cell disease, or SCD, is a group of inherited blood disorders affecting hemoglobin, the protein in red blood cells that carries oxygen.

In SCD, abnormal hemoglobin can cause red blood cells to become rigid and take on a sickled shape under certain conditions. The disease involves more than abnormal cell shape alone. Hemolysis, inflammation, activation of blood vessel lining, cellular adhesion, and impaired blood flow all contribute to its complications.

A vaso-occlusive episode occurs when this complex process disrupts blood flow and causes tissue ischemia and pain.

Pain can occur in different parts of the body, including the:

• back;
• chest;
• arms;
• legs;
• abdomen;
• hands;
• feet; and
• joints or bones.

The experience varies considerably. One person may have relatively infrequent episodes, while another may experience recurrent acute pain, chronic pain, or both.

Pain intensity can also vary between episodes in the same person.

What Can Trigger a Sickle Cell Pain Crisis?

Not every vaso-occlusive episode has an identifiable trigger. A crisis may occur even when a person has followed their treatment and self-care plan carefully.

However, some people identify circumstances associated with their own episodes. Potential contributors can include:

• dehydration;
• infection or illness;
• temperature extremes or sudden temperature changes;
• low-oxygen environments;
• significant physical overexertion;
• emotional or physiological stress; and
• other individual factors.

Triggers are not identical for everyone, and avoiding every possible trigger cannot guarantee that a crisis will not occur.

The original version of this article listed “moodiness” as a cause of sickle cell crisis. That characterization is inappropriate and unsupported. Emotional stress may affect health and pain experiences, but a vaso-occlusive episode is a biological complication of sickle cell disease, not a consequence of a person’s attitude or mood.

What Does a Sickle Cell Crisis Feel Like?

Sickle cell pain can be severe and difficult to describe.

People may describe the pain as:

• sharp;
• stabbing;
• throbbing;
• aching;
• crushing;
• deep;
• burning; or
• difficult to localize.

The pain may begin suddenly or build over time. It can affect one location or several areas simultaneously.

A person’s own report of pain is central to assessment. Laboratory tests and imaging do not provide a direct measurement of how much pain someone is experiencing.

This matters because people with SCD can face delays, disbelief, or stigma when seeking treatment for acute pain. Effective care requires prompt assessment and an individualized approach rather than assumptions based on appearance alone.

What Should You Do During a Sickle Cell Pain Crisis?

People with SCD should follow the individualized pain plan developed with their healthcare team.

The appropriate response depends on the severity of the episode and whether other symptoms are present.

For an episode that the person’s clinical plan identifies as appropriate for home management, the plan may include prescribed pain medicines and other supportive measures recommended by the treating team.

People should not take more medication than prescribed or combine medicines in ways that have not been reviewed by a healthcare professional.

If pain is severe, rapidly worsening, different from usual episodes, or not responding to the established home treatment plan, medical evaluation may be necessary.

Certain symptoms can indicate complications that require urgent or emergency care rather than continued home management.

When Is a Sickle Cell Crisis an Emergency?

Severe pain is not the only reason a person with SCD may need urgent evaluation.

Seek urgent medical care according to the patient’s emergency plan and local emergency services when serious symptoms occur, particularly symptoms such as:

• difficulty breathing or significant shortness of breath;
• chest pain;
• fever;
• sudden weakness or numbness;
• facial drooping;
• difficulty speaking or understanding speech;
• sudden confusion;
• severe headache with neurological changes;
• seizure;
• loss of consciousness;
• severe abdominal swelling or pain;
• sudden marked paleness or extreme weakness;
• a prolonged painful erection;
• rapidly worsening symptoms; or
• severe pain that cannot be controlled with the established home plan.

SCD can cause serious complications including acute chest syndrome, severe infection, stroke, splenic sequestration, and other organ-related emergencies.

Symptoms should not automatically be attributed to an ordinary pain crisis without appropriate assessment.

How Is an Acute Sickle Cell Crisis Treated?

Treatment of an acute vaso-occlusive episode is individualized.

The goals are to relieve pain, identify complications, address contributing medical problems, and support recovery.

Rapid Pain Assessment and Treatment

Acute SCD pain requires timely assessment.

The treatment plan may use nonopioid analgesics, opioid medications, or combinations of therapies depending on pain severity, previous response, contraindications, and the patient’s individualized plan.

For severe acute pain, opioids may be clinically appropriate. Treatment should be individualized and monitored rather than delayed because of generalized assumptions about people seeking care for recurrent pain.

The patient’s previous effective treatment plan can be particularly valuable because SCD pain experiences vary widely.

Hydration and Fluid Management

Dehydration may contribute to sickling and can require correction, but fluid treatment needs to be individualized.

Some patients may need oral fluids, while others may receive intravenous fluids when clinically indicated.

More fluid is not automatically better. Excessive intravenous fluid can be harmful in some clinical situations, particularly when cardiopulmonary complications are present.

Fluid management should therefore be based on clinical assessment rather than a one-size-fits-all approach.

Evaluation for Infection and Other Complications

Fever and signs of infection require prompt attention in people with SCD because the disease can impair splenic function and increase susceptibility to serious infection.

Clinicians may also evaluate for other complications depending on the symptoms and examination findings.

Chest symptoms, for example, require careful evaluation because acute chest syndrome can develop during hospitalization for a pain episode and can become life-threatening.

Oxygen When Clinically Indicated

Oxygen therapy is used when a patient has hypoxemia or another clinical indication.

It is not a universal treatment for every uncomplicated pain crisis. Clinicians assess oxygen saturation and the overall respiratory condition when deciding whether supplemental oxygen is needed.

Acute Chest Syndrome Is Different From an Uncomplicated Pain Crisis

Acute chest syndrome is a serious pulmonary complication of SCD.

It may involve symptoms and findings such as:

• chest pain;
• fever;
• cough;
• breathing difficulty;
• low oxygen levels; and
• a new pulmonary infiltrate on chest imaging.

It can occur during or after the beginning of a vaso-occlusive episode.

Treatment depends on severity and the clinical situation and may involve respiratory support, treatment of suspected infection, pain management that balances adequate analgesia with respiratory safety, and transfusion therapy in selected cases.

Because acute chest syndrome can progress rapidly, new chest or breathing symptoms during a pain crisis require prompt medical assessment.

How Can Future Sickle Cell Crises Be Reduced?

Acute treatment addresses the immediate episode. Disease-modifying treatment aims to reduce future complications or change the underlying disease process.

The appropriate strategy depends on factors including:

• SCD genotype;
• age;
• frequency and severity of vaso-occlusive episodes;
• previous acute chest syndrome;
• stroke risk;
• anemia and hemolysis;
• organ function;
• previous treatments;
• pregnancy considerations;
• access to specialized care; and
• patient goals and preferences.

Treatment decisions should be made with clinicians experienced in SCD.

1. Hydroxyurea

Hydroxyurea is a foundational disease-modifying treatment for sickle cell disease.

Among its effects, hydroxyurea can increase fetal hemoglobin, or HbF. Higher HbF levels can reduce the tendency of sickle hemoglobin to polymerize and contribute to red blood cell sickling.

Hydroxyurea has been shown to reduce important complications, including pain crises and acute chest syndrome, in appropriate patient populations.

The original article described hydroxyurea as the only FDA-approved drug for SCD. That statement is outdated. The SCD treatment landscape has expanded considerably since the original article was written.

Hydroxyurea nevertheless remains a major component of SCD care because of its established evidence base and clinical experience.

Treatment requires appropriate prescribing and monitoring. Blood counts and other laboratory tests may be checked according to the treatment protocol and individual clinical situation.

Patients should discuss benefits, potential adverse effects, reproductive considerations, adherence, and monitoring with their hematology team.

2. Other Disease-Modifying Medications

The medication landscape for SCD has evolved beyond hydroxyurea.

In the United States, additional therapies have been approved for specific SCD populations and indications, including treatments intended to reduce acute complications or vaso-occlusive events.

Medication selection is individualized. A therapy appropriate for one patient may not be suitable for another because of differences in age, disease manifestations, previous treatment, access, contraindications, and treatment goals.

The treatment landscape can also change as regulators review new evidence.

One important example is voxelotor, formerly marketed as Oxbryta. It was voluntarily withdrawn from the market in 2024 after emerging safety data led to concerns that its benefits no longer outweighed its risks in the SCD population.

This history illustrates why medication information for SCD should be based on current regulatory and clinical guidance rather than older lists of approved treatments.

Patients should not start, stop, or switch SCD medication based solely on general online information. Changes should be discussed with the treating clinician.

3. Blood Transfusion Therapy

Red blood cell transfusion is an important treatment for specific complications and clinical situations in SCD.

Transfusion may be used in contexts including:

• treatment of selected severe acute complications;
• stroke prevention in certain high-risk patients;
• management of some cases of acute chest syndrome;
• severe anemia in appropriate clinical settings;
• selected perioperative situations; and
• chronic transfusion programs for specific indications.

There are different transfusion approaches, including simple transfusion and red cell exchange.

Transfusion is not a routine treatment for every uncomplicated pain episode. The decision depends on the clinical indication.

Repeated transfusions also carry potential risks, including alloimmunization and iron overload. Transfusion support in SCD therefore requires careful blood matching, monitoring, and specialist management.

4. Hematopoietic Stem Cell Transplantation

Allogeneic hematopoietic stem cell transplantation can offer a curative treatment pathway for selected people with SCD.

The procedure replaces the patient’s blood-forming system with hematopoietic stem cells from a donor.

Historically, the best-established approach involved a suitably matched sibling donor. Advances in transplantation have expanded research and clinical experience with other donor strategies, but transplantation remains a complex treatment with significant potential risks.

Possible complications include:

• graft-versus-host disease;
• graft rejection or failure;
• serious infection;
• organ toxicity;
• infertility;
• treatment-related complications; and
• death.

The balance of benefits and risks differs from person to person.

Transplantation should therefore be evaluated through specialized multidisciplinary care and shared decision-making. The question is not simply whether transplantation can cure SCD, but whether a particular transplant strategy offers an acceptable risk-benefit balance for a specific patient.

5. Gene Therapy for Sickle Cell Disease

Gene therapy has transformed the treatment landscape for SCD.

In December 2023, the FDA approved the first cell-based gene therapies for sickle cell disease: Casgevy and Lyfgenia.

These treatments use a patient’s own blood-forming stem cells, which are collected and genetically modified before being returned to the patient after a conditioning regimen.

The therapies use different strategies.

Casgevy uses CRISPR/Cas9 genome editing to modify a regulatory region involved in fetal hemoglobin production. The goal is to increase fetal hemoglobin and reduce sickling-related complications.

Lyfgenia uses a lentiviral vector to introduce a modified form of the beta-globin gene into the patient’s blood-forming stem cells.

These are not simple injections or routine outpatient medications. Treatment involves specialized centers, stem cell collection, manufacturing, conditioning chemotherapy, infusion of modified cells, and prolonged follow-up.

Potential risks differ between products and treatment pathways. Patients considering gene therapy need detailed counseling about:

• eligibility;
• expected benefits;
• conditioning treatment;
• short- and long-term risks;
• fertility considerations;
• hospitalization and recovery;
• long-term monitoring; and
• uncertainty about very long-term outcomes.

Gene therapy represents a major advance, but access, infrastructure, cost, eligibility, and long-term follow-up remain important practical considerations.

Stem Cell Transplant vs. Gene Therapy: What Is the Difference?

Both approaches aim to fundamentally change blood cell production, but they are not the same.

A stem cell transplant generally uses blood-forming stem cells from a donor. This creates risks related to donor compatibility, graft rejection, and graft-versus-host disease.

Current gene therapy approaches use the patient’s own stem cells. Those cells are genetically modified outside the body and returned after conditioning.

Using autologous cells avoids the need to find a donor and avoids graft-versus-host disease, but gene therapy has its own risks and complexities.

Both approaches require specialized evaluation. Neither should be presented as an easy or universally appropriate cure.

What About Chronic Pain Between Crises?

Not all SCD pain occurs as separate acute crises.

Some people develop chronic pain that persists on most days or recurs frequently. The mechanisms can be complex and may involve tissue damage, avascular necrosis, chronic inflammation, neuropathic mechanisms, and changes in pain processing.

Chronic pain management differs from treatment of an isolated acute vaso-occlusive episode.

A comprehensive plan may involve:

• treatment of underlying SCD;
• individualized pharmacologic management;
• evaluation of specific pain generators;
• physical or rehabilitative approaches;
• behavioral health support;
• sleep assessment;
• functional goals; and
• coordinated care among appropriate specialists.

The presence of chronic pain does not make acute pain episodes less real. A person can experience chronic pain and still develop superimposed vaso-occlusive episodes requiring acute treatment.

Why Individualized Pain Plans Matter

People with SCD often know which treatments have helped or failed during previous crises.

An individualized pain plan can document clinically relevant information such as:

• usual home treatments;
• previous effective emergency treatments;
• medication allergies;
• relevant complications;
• preferred routes of medication administration;
• monitoring requirements; and
• contact information for the treating SCD team.

The plan does not remove the need for clinical assessment. Instead, it can help reduce unnecessary delays and support continuity between outpatient specialists and emergency care teams.

Timely treatment is particularly important because people with SCD have historically experienced inequities and stigma in pain care.

Can Sickle Cell Crises Be Completely Prevented?

No available strategy can guarantee that every vaso-occlusive episode will be prevented in every person with SCD.

However, modern care can substantially reduce disease burden for many patients.

Depending on the individual, prevention strategies may include:

• disease-modifying medication;
• appropriate vaccination and infection prevention;
• regular specialist follow-up;
• stroke risk assessment and prevention strategies;
• transfusion therapy for specific indications;
• attention to hydration and individual triggers;
• management of coexisting medical problems;
• reproductive and genetic counseling when desired;
• stem cell transplantation for selected patients; and
• gene therapy for eligible patients.

Access to comprehensive SCD care remains uneven. A treatment that exists scientifically may still be difficult to obtain because of geography, specialist availability, healthcare infrastructure, insurance coverage, or cost.

Living With Sickle Cell Disease Beyond the Crisis

SCD is a lifelong systemic disease, not simply a series of isolated pain episodes.

Potential complications can affect multiple organ systems and may include:

• acute chest syndrome;
• stroke and silent cerebral infarction;
• anemia;
• kidney disease;
• pulmonary complications;
• eye disease;
• avascular necrosis and other bone problems;
• leg ulcers;
• priapism;
• gallstones;
• liver complications; and
• other forms of organ damage.

Regular comprehensive care is therefore important even during periods when a person is not experiencing severe pain.

Mental health, education, employment, family support, reproductive planning, and transition from pediatric to adult care can also affect long-term health and quality of life.

The Bottom Line

A sickle cell crisis, also called a vaso-occlusive episode, can cause sudden and severe pain when the complex disease processes of SCD impair blood flow and injure tissues.

Acute treatment should be individualized and timely. Depending on severity and clinical circumstances, care may include pain medication, carefully selected supportive treatment, and evaluation for complications such as infection or acute chest syndrome.

Long-term treatment has changed dramatically. Hydroxyurea remains a foundational therapy, while other disease-modifying treatments, transfusion strategies, stem cell transplantation, and gene therapy have expanded the options available to selected patients.

The most important distinction is between treating today’s crisis and reducing tomorrow’s risk. People living with SCD benefit from an individualized plan developed with a healthcare team experienced in the disease, including clear instructions for home treatment, emergency warning signs, and long-term disease-modifying care.

Anyone experiencing severe or unusual symptoms should seek appropriate medical evaluation rather than assuming every new symptom is an uncomplicated pain crisis.