Myelosuppression: Symptoms, Causes, Treatment and Safety
Updated: 3 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 2026
Quick Answer: What is myelosuppression?
Myelosuppression is reduced production of blood cells or platelets by the bone marrow, most commonly caused by chemotherapy. Symptoms depend on the cells affected, including fatigue, infections, bruising or bleeding. A complete blood count diagnoses it, and treatment may involve monitoring, transfusions or supportive medicines. Fever, severe breathing symptoms or uncontrolled bleeding need prompt attention. [1]
What the research says
Febrile neutropenia is common during chemotherapy: about one in five adults with diffuse large B-cell lymphoma on first-line R-CHOP-type treatment developed it in routine practice. A systematic review and meta-analysis of 15 studies (5,440 patients; 885 events) found a pooled incidence of 19.0% across ten observational cohorts (4,020 patients; 95% CI 17.1–21.1). Five clinical trials (1,420 patients) reported 11.7%, but their results varied widely (2.4% to 20.0%), so trial figures may understate what happens in everyday care (Reyes & Reyes, Supportive Care in Cancer, 2026). [2]
Protecting the marrow before chemotherapy can reduce severe neutropenia; one such medicine, trilaciclib, is FDA-approved for small-cell lung cancer. In a pooled analysis of four randomized, double-blind, placebo-controlled studies in 325 people with extensive-stage small-cell lung cancer (164 on trilaciclib, 161 on placebo), giving trilaciclib before chemotherapy reduced the duration of severe neutropenia in cycle 1 and the incidence of severe neutropenia and febrile neutropenia. Median progression-free survival was 5.3 vs 4.9 months and median overall survival 10.9 vs 10.1 months. Whether any such medicine is appropriate is a decision for the oncology team (Liu et al., Cancer Treatment and Research Communications, 2025). [3]
What does bone marrow do?
Bone marrow is soft, spongy tissue inside bones. Every day, it produces and releases billions of red blood cells, white blood cells and platelets. [1]
Each cell type has a different role. Red blood cells carry oxygen throughout the body. White blood cells, including neutrophils, help destroy germs that cause infection. Platelets help control bleeding. [1]
Bone marrow adjusts production as the body’s needs change. Myelosuppression occurs when something interferes with that process. [1]
What are the three blood-cell effects?
The symptoms of myelosuppression depend on which blood cells or platelets are low. One person may have one low cell line, while another may have more than one. [1]
Red blood cells: anemia
Anemia happens when there are not enough red blood cells. Because red blood cells carry oxygen, anemia can cause fatigue, shortness of breath, dizziness, a fast or irregular heartbeat, a pounding or whooshing sound in the ear, headache, paler-than-usual skin or chest pain. [1]
White blood cells: neutropenia
Neutrophils are white blood cells that destroy germs that cause infections. A lower-than-normal neutrophil level is called neutropenia. [1]
Neutropenia itself does not cause symptoms. The infections that may occur when neutrophil levels are low can cause symptoms. Repeated infections may also be a sign. Possible infection symptoms include fever, fatigue, sore throat, swollen lymph nodes, ulcers in the mouth or around the anus, diarrhea and burning, urgency or increased frequency when urinating. [1]
Platelets: thrombocytopenia
Platelets help control bleeding. A low platelet level is called thrombocytopenia. [1]
Possible signs include a cut or nosebleed that will not stop, bruises that appear more often than usual, petechiae that may look like a rash on the lower legs and purpura that may appear as red, purple or brown spots on the skin. [1]
All three: pancytopenia
When red blood cells, white blood cells and platelets are all low, the pattern is called pancytopenia. Pancytopenia is not a disease by itself, but it may be a sign of an underlying condition. [1]
Cell or component | Main role | Low level may be called | Common concern |
Red blood cells | Carry oxygen through the body. | Anemia. | Fatigue, shortness of breath, dizziness or chest pain. |
Neutrophils | Help destroy germs that cause infections. | Neutropenia. | Increased risk of infection. |
Platelets | Help control bleeding. | Thrombocytopenia. | Bruising, petechiae, purpura or bleeding. |
All three lines | Red cells, white cells and platelets are low. | Pancytopenia. | May signal an underlying condition and needs clinical evaluation. |
What causes myelosuppression?
Chemotherapy for cancer is the most common cause. Some blood cancers, viruses and immunotherapies can also affect bone marrow and reduce production of blood cells or platelets. [1]
Chemotherapy and immunotherapy
Several chemotherapy medicines can cause myelosuppression. Examples include fluorouracil, oxaliplatin, irinotecan and capecitabine. [1]
CAR T-cell therapy is a type of immunotherapy that may affect bone marrow so it produces fewer blood cells and platelets. The risk and timing depend on the treatment and the person’s situation, so the oncology team monitors blood counts throughout care. [1]
Never stop, skip or change cancer treatment because of a symptom or lab result without speaking with the treatment team.
Blood cancers
Blood cancers can interrupt normal blood-cell production. In leukemia, lymphoma and myeloma, abnormal blood cells may multiply in bone marrow and keep it from producing healthy blood cells and platelets. [1]
Viruses
Some viruses can disrupt blood-cell production. Viruses linked with myelosuppression include Epstein-Barr virus, hepatitis C virus, parvovirus 19, cytomegalovirus, chickenpox or varicella zoster, HIV and dengue fever.
A virus associated with myelosuppression is not necessarily the cause of a particular person’s low counts. Testing and interpretation belong to a healthcare professional.
Cause group | Examples described in clinical care |
Cancer treatment | Chemotherapy and CAR T-cell therapy. |
Blood cancers | Leukemia, lymphoma and myeloma. |
Viruses | Epstein-Barr virus, hepatitis C, parvovirus 19, cytomegalovirus, chickenpox, HIV and dengue fever. |
What complications can occur?
Myelosuppression can cause serious or life-threatening complications. Acute anemia can reduce oxygen delivery. Low platelets can lead to uncontrollable bleeding. Low neutrophils can increase the risk of infection. [1]
The severity of risk depends on the blood counts, the underlying condition, treatment and overall health. A symptom that seems minor during cancer treatment can deserve a prompt call because low counts may change how the body responds.
Seek prompt medical guidance for
Fever of 100.4°F (38°C) or higher, or other signs of infection: call right away, day or night.
A sore throat with illness or repeated infections. [1]
Mouth or anal ulcers.
Diarrhea or burning, urgency or increased frequency with urination. [1]
A cut or nosebleed that will not stop.
Frequent new bruises, petechiae or purpura.
Chest pain, severe shortness of breath, dizziness or a fast or irregular heartbeat.
If there is severe breathing difficulty, chest pain, uncontrolled bleeding, collapse or another immediate emergency, use local emergency services. Do not wait for the next scheduled treatment visit.
How is myelosuppression diagnosed?
Myelosuppression is diagnosed with blood tests, such as a complete blood count, that show whether bone marrow is producing normal numbers of blood cells and platelets. Tests may include:
A complete blood count, or CBC.
Mean corpuscular volume, or MCV.
Red cell distribution width, or RDW.
Reticulocyte count.
Peripheral blood smear.
Mean platelet volume, or MPV.
The results are interpreted together with symptoms, medications, cancer treatment, infections and other clinical information. One test result does not explain every cause of low counts.
What a CBC can help show
A CBC can show the levels of red blood cells, white blood cells and platelets. Additional blood measures can help healthcare professionals examine red-cell size, variation in red-cell size, newly produced red cells, blood-cell appearance and platelet size. [1]
Ask the care team which numbers are low, what symptoms to watch for and when the next blood test will happen. Avoid comparing a personal result with a standard range found online without clinical interpretation.
How is myelosuppression treated?
Treatment focuses on what is affecting the bone marrow and which blood cells or platelets are low. Depending on the situation, healthcare professionals may reduce or temporarily stop the chemotherapy that caused myelosuppression, provide a blood transfusion to increase red blood cell or platelet levels, provide treatment that helps bone marrow produce more blood cells and platelets, and monitor blood counts while the marrow recovers.
If myelosuppression occurs during chemotherapy, the oncology team may recommend a brief treatment break while blood-cell levels build back up. A pause or adjustment is a medical decision; do not make it independently. [1]
Treatment approach | Purpose |
Monitoring | Track blood-cell and platelet levels and watch for symptoms. |
Treatment adjustment | Reduce or temporarily pause the treatment affecting bone marrow when clinically appropriate. |
Transfusion | Increase red-cell or platelet levels when indicated. |
Marrow-supporting treatment | Help bone marrow produce more blood cells and platelets when appropriate. |
Cause-directed care | Address the cancer, infection or other condition affecting marrow production. |
Can myelosuppression be prevented?
Myelosuppression commonly happens during cancer treatment. Healthcare professionals reduce risk by monitoring treatment side effects and blood counts. [1]
You may be able to reduce infection and bleeding risk by following the care team’s vaccination guidance, washing your hands regularly, avoiding people who are sick when the care team recommends it and protecting yourself from situations where you could be injured or cut.
Vaccination decisions can depend on cancer treatment, immune status and timing. Ask the oncology team which vaccines are appropriate and when to receive them.
Do not take a new medicine, supplement or over-the-counter product for low counts without checking with the care team. Do not change cancer treatment on your own.
How can people live with myelosuppression during treatment?
Myelosuppression can make an already difficult treatment period feel uncertain. The goal is not to memorize every possible symptom; it is to know which changes deserve a call and how to reach the treatment team.
Keep a written list of medicines, treatment dates, recent blood-test results and symptoms. Ask whether the oncology service has a dedicated number for fever, bleeding or sudden changes.
Follow the team’s instructions about hand hygiene, contact with people who are ill, injury prevention, vaccines and when to repeat blood tests. The plan may change as counts recover or treatment changes.
Questions to ask the care team
Which blood-cell line is low: red cells, neutrophils, platelets or more than one?
What are my current blood counts, and how are they changing?
Which symptoms should prompt a same-day call?
What temperature or fever instructions should I follow?
Should I avoid certain activities because of infection or bleeding risk?
What should I do if I have a cut, nosebleed, bruising or a rash-like spot?
Could my treatment schedule or dose change?
Would a transfusion or marrow-supporting treatment be appropriate?
When is my next CBC or other blood test?
Which vaccines are appropriate during my treatment?
Which medicines, supplements or over-the-counter products should I avoid?
Conclusion: Low counts deserve a clear plan
Myelosuppression means the bone marrow is not making enough blood cells or platelets. It most often happens during chemotherapy, but blood cancers, viruses and CAR T-cell therapy can also affect marrow production. [1]
The pattern of low counts shapes the concern. Anemia can cause fatigue and shortness of breath. Neutropenia raises infection risk. Thrombocytopenia can cause bruising or bleeding. When all three cell lines are low, the pattern is called pancytopenia. [1]
Healthcare professionals use blood tests to diagnose and monitor myelosuppression. Treatment may include a clinician-guided adjustment in cancer therapy, transfusions or treatment that supports blood-cell production. Good hand hygiene, avoiding illness when advised and reducing injury risk can help lower complications. [1]
If you are receiving cancer treatment and develop fever, infection symptoms, chest pain, severe breathing symptoms or bleeding that will not stop, contact your oncology team promptly or use local emergency services for an immediate emergency. Ask your care team for a written low-count safety plan. [1]
Frequently Asked Questions
Is myelosuppression the same as anemia?
No. Myelosuppression is reduced production of blood cells or platelets by bone marrow. Anemia is the low-red-blood-cell effect that can result from myelosuppression. Myelosuppression can also cause neutropenia, thrombocytopenia or pancytopenia.
What is the most common cause of myelosuppression?
Chemotherapy used to treat cancer is the most common cause described. Certain blood cancers, viruses and CAR T-cell therapy can also affect bone marrow.
What are the main symptoms of myelosuppression?
Symptoms vary by the cell line affected. Anemia may cause fatigue, shortness of breath, dizziness, headache or chest pain. Low neutrophils may lead to infections with fever, sore throat, mouth ulcers or urinary symptoms. Low platelets may cause bruising, petechiae, purpura or bleeding that will not stop.
Does neutropenia cause symptoms?
Neutropenia itself does not cause symptoms. The infections that may result from low neutrophils can cause symptoms, and repeated infections may be a sign of neutropenia.
What is pancytopenia?
Pancytopenia is when red blood cells, white blood cells and platelets are all low. It is not a disease by itself, but it may signal an underlying condition.
Which blood tests diagnose myelosuppression?
Tests may include a complete blood count, mean corpuscular volume, red cell distribution width, reticulocyte count, peripheral blood smear and mean platelet volume. The care team interprets the results together with symptoms and medical history.
Will myelosuppression stop chemotherapy?
A healthcare professional may reduce or temporarily stop chemotherapy when it is causing myelosuppression. Some people need a brief treatment break while blood-cell levels recover. Never pause, skip or change treatment without speaking with the oncology team.
How is myelosuppression treated?
Treatment depends on the cause and which cell lines are low. Options may include monitoring, adjusting the treatment that caused the suppression, blood transfusions and treatment that helps bone marrow produce more blood cells and platelets.
Can myelosuppression be prevented?
Myelosuppression may not be completely preventable, especially when it is related to cancer treatment. Healthcare professionals reduce risk by monitoring blood counts and treatment side effects. Hand hygiene, avoiding sick people when advised and preventing cuts or injuries can reduce infection and bleeding risks.
Should I get vaccinated if I have myelosuppression?
Ask the oncology team which vaccines are appropriate and when to receive them. Vaccine decisions depend on the treatment and immune status; do not assume every vaccine is suitable at every point in care.
When should I call my oncology team?
Call promptly for fever, signs of infection, repeated infections, a cut or nosebleed that will not stop, frequent new bruises, petechiae, purpura, chest pain, severe shortness of breath, dizziness or a fast or irregular heartbeat.
When is myelosuppression an emergency?
Uncontrolled bleeding, chest pain, severe breathing difficulty, collapse or another immediate emergency needs local emergency services. A fever of 100.4°F (38°C) or higher during chemotherapy is an emergency: call the oncology team right away, day or night, or go to the emergency room.
Can viruses cause myelosuppression?
Yes. Viruses linked with myelosuppression include Epstein-Barr virus, hepatitis C, parvovirus 19, cytomegalovirus, chickenpox or varicella zoster, HIV and dengue fever. A healthcare professional must determine whether a virus is involved in an individual case.
Can blood cancer cause myelosuppression?
Yes. In leukemia, lymphoma and myeloma, abnormal blood cells may multiply in bone marrow and interrupt production of healthy blood cells and platelets.
Does myelosuppression go away?
The course depends on the cause, treatment and overall health. During cancer treatment, blood-cell levels may recover after monitoring or a clinician-guided treatment break, but the care team must follow the counts and address the underlying cause.
Related guides
References
Cleveland Clinic. Myelosuppression (Bone Marrow Suppression). Cleveland Clinic. Last updated February 27, 2023. https://my.clevelandclinic.org/health/diseases/24788-myelosuppression
Reyes J, Reyes A. Febrile neutropenia in adults with diffuse large B-cell lymphoma receiving first-line R-CHOP-based therapy: a systematic review and meta-analysis of observational and trial evidence. Support Care Cancer. 2026;34(10):1065. PMID 42839187. https://doi.org/10.1007/s00520-026-11301-w
Liu Y, Wu L, Huang D, et al. Effect of trilaciclib administered before chemotherapy in patients with extensive-stage small-cell lung cancer: a pooled analysis of four randomized studies. Cancer Treat Res Commun. 2024;42:100869. PMID 39823755. https://doi.org/10.1016/j.ctarc.2025.100869
Centers for Disease Control and Prevention. Neutropenia and Risk for Infection. CDC. Updated February 13, 2025. https://www.cdc.gov/cancer-preventing-infections/patients/neutropenia.html
Centers for Disease Control and Prevention. What Vaccines are Recommended for You. CDC. Updated June 12, 2024. https://www.cdc.gov/vaccines-adults/recommended-vaccines/index.html
Disclaimer
This article is for general educational purposes and is not a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of a qualified healthcare professional with any questions about a medical condition or treatment.
It is not a lab-result interpretation, cancer-treatment recommendation or substitute for emergency triage. Do not stop, skip or change chemotherapy, immunotherapy, prescription drugs, supplements or vaccines without speaking with your oncology team.
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