Care Guide: Blood-Related Side Effects

Learn about potential blood-related side effects of cancer treatment that may affect your child.

Bone Marrow Side Effects

Bone marrow cells (soft tissue inside the bones) make blood cells that are released into the bloodstream when they are needed. Cells of the bone marrow can be injured by cancer cells, chemotherapy and radiation. This causes low blood counts, also referred to as bone marrow suppression.

Blood Counts

Three important types of cells produced in the bone marrow are red blood cells (RBCs), white blood cells (WBCs) and platelets. The patient’s blood counts will be checked by the treatment team as often as necessary. Blood counts may reach their lowest point 5 to 14 days after chemotherapy and/or radiation therapy was given. Low counts or bone marrow suppression may cause treatment delays, therapy changes and unscheduled trips to the hospital.

Red Blood Cells (RBCs)

RBCs contain hemoglobin, which carries oxygen in the blood. When the hemoglobin is low, the patient is said to be anemic, and you may notice that the patient tires easily and looks pale. If the hemoglobin drops to a certain level, your doctor may order a red blood cell transfusion.

White Blood Cells (WBCs)

WBCs fight infections. When the WBC count is low, the patient has an increased chance of getting an infection. There are different kinds of white blood cells and it is the neutrophils (also known as granulocytes or polys) that fight bacteria. The absolute neutrophil count (ANC) will be calculated by the treatment team. When the ANC is low, the patient has a greater chance of getting a bacterial infection. When the treatment team informs you that the patient’s white blood cell counts are low, reporting of fever or infection is especially important. Learn more about preventing infection.


Platelets are needed for the blood to clot normally. When the patient’s platelet count is low (thrombocytopenia), he or she may bleed easily. Signs and symptoms of a low platelet count are:

  • Increased bruising
  • Petechiae – purple or red dots on the skin (pinpoint bruises) that look like a rash
  • Bleeding from small cuts, scrapes, gums or the nose that is hard to stop

When the platelet count drops below a certain level, your doctor may order a platelet transfusion.

Injury & Bleeding

When the treatment team informs you that you need to take special steps to protect the patient from injury, follow these guidelines:

  • Avoid contact sports (football, soccer), rough play (skateboarding, bicycling) or amusement park rides that could cause body or head injury
  • Use a soft-bristled toothbrush, a tooth sponge or a clean, soft cloth to gently clean the teeth
  • Do not schedule dental procedures or teeth cleaning when the platelet count is low
  • Do not take rectal temperatures or use rectal suppositories, as this could tear the lining of the rectum and cause bleeding
  • If the patient is constipated, the doctor may order stool softeners, because hard bowel movements can cause rectal bleeding

If bleeding does occur while the platelet count is low, it may be hard to stop. The following guidelines may help you in specific situations:


  • Keep the patient in an upright (sitting) position
  • Instruct the patient to breathe through the mouth
  • Apply pressure by gently but firmly pinching the nostril closed on side which is bleeding and continue this pressure for 10 minutes without stopping
  • If the bleeding still does not stop, continue pressure and call the treatment team
  • Once the nosebleed has stopped, do not allow the patient to sniff hard, blow, or pick the nose

Bleeding of the Gums or Mouth

  • If the bleeding is in an area that is easy to reach, apply pressure until the bleeding stops
  • If you cannot apply pressure, try to have the patient hold ice water in their mouth until the bleeding stops

A Bleeding Cut

  • With a clean, dry cloth, apply pressure over the cut for at least 10 minutes without stopping
  • If the bleeding does not stop, continue pressure and call your treatment team
  • If a cut is deep, apply pressure without stopping and take the patient to the nearest emergency department at once

Bleeding Under the Skin

Hold pressure with an ice pack over the area for at least 10 minutes without stopping and call the treatment team.